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Dissertations / Theses on the topic 'Electropolishing'
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Saleem, Saima. "Electropolishing in deep eutectic solvents." Thesis, University of Leicester, 2014. http://hdl.handle.net/2381/28577.
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A fundamental study of electropolishing of stainless steel and nickel based single crystal superalloy CMSX-4 in type III deep eutectic solvent based on choline chloride and hydrogen bond donor i.e. mixture of choline chloride with ethylene glycol in a 1:2 molar ratio was carried out and had been found to be competitive with the current concentrated mixture of inorganic acid electrolytes. Life cycle study was conducted to define the key process controlling factors like electrochemical stability, current efficiency, effect of history of electrolyte, recycling of ionic liquid and its reuse for electropolsihing. The electrochemical techniques like linear sweep anodizing curves, chronoamperometery and galvanostatic studies revealed that electropolishing in 1:2 ChCl:EG proceeded through the formation of viscous layer on the surface of the substrate similar to electropolishing in inorganic acid electrolytes. The optimization of electropolishing process was carried out using the experimental design strategies, Fractional Factorial Design (FFD) and found that electropolishing variables like addition of water, oxalic acid, electropolishing bath temperature, time and potential had positive impact on the surface finish. Surface texture measurements such as surface roughness and surface overlayer morphology of electropolished stainless steel and CMSX-4 was carried out using the microscopic techniques, atomic force microscopy (AFM), scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM) and digital holographic microscopy (DHM) and found to be the function of electropolishing time. Effect of electropolishing on corrosion behaviour of stainless steel was studied using the electrochemical techniques like open circuit potential measurements (OCP), potentiodynamic polarization curves and gravimeteric method showed improvement in the general or pitting corrosion of the workpiece. Nickel based superalloy was also successfully electropolished to remove the casting scales. The dissolution of two phases was found to be the function of electrochemical regime i.e. applied potential and current density.
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Chandra, Ashwini. "On the Mechanism of Niobium Electropolishing." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1330544777.
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Mousselli, Jad. "On surface electropolishing for the development of metallic stents." Master's thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/36574.
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Les maladies cardiovasculaires sont responsables d'environ le tiers de tous les cas de décès au Canada. L'une des solutions utilisées pour résoudre ce problème consiste à utiliser un dispositif métallique constitué d'un maillage ayant une forme d’un filet et appelé stent. Les stents sont de petits dispositifs implantés dans des vaisseaux sanguins rétrécis pour rétablir la circulation sanguine et éviter une crise cardiaque ou un accident vasculaire cérébral et pour traiter les anévrismes du cerveau. Un contrôle précis de la surface de ces stents est nécessaire pour assurer la compatibilité de l'alliage choisi avec le milieu biologique dont il va être en contact avec. Les stents métalliques doivent satisfaire à des conditions précises définies en fonction de leur application finale. Ils doivent respecter des exigences strictes en termes de propriétés mécaniques, d'interaction électrochimique (corrosion) et de cytocompatibilité. Les alliages suivants sont traditionnellement utilisés dans les applications biomédicales et plus précisément pour les applications cardiovasculaires: l'alliage AISI316L est considéré comme une référence dans ce domaine, mais l'alliage L605, un alliage à base de Cobalt, prend de plus en plus d'importance grâce à ses propriétés mécaniques élevées (haute ductilité et haute résistance à la traction) et résistance élevée à la corrosion. L'utilisation d'alliages de titane est la nouvelle frontière pour les biomatériaux dans les applications cardiovasculaires, il est considéré comme un nouveau candidat potentiel pour les stents cardiovasculaires. Les alliages de titane présentent une combinaison unique de haute résistance et de grande ductilité (résistance à la traction et déformation uniforme supérieures à 1000 MPa et 30% respectivement). L’électropolissage est une étape de prétraitement appliquée à ces alliages métalliques pour obtenir des surfaces chimiquement homogènes, recouvertes d'une couche d'oxyde uniforme et amorphe, généralement de rugosité très lisse. Ce processus permet non seulement de contrôler les propriétés physiques de la surface, mais également celles chimiques. Le processus d'électropolissage comporte certaines variables, telles que le courant, la tension, la solution électrolytique et la température de l'électrolyte. En les contrôlant, il est possible de comprendre et d'améliorer les propriétés de la surface. Le but de ce projet est d’étudier les effets des différents variables d’électropolissage (courant, tension, solution électrolytique) sur les caractéristiques / propriétés de surface (morphologie, composition chimique et mouillabilité) des alliages utilisés pour la fabrication de stents.Cardiovascular diseases (CVD) are responsible for about one-third of all death cases in Canada. One of the solutions used to solve this problem is using a metallic device made of a mesh and called a stent. Stents are small devices that are implanted in narrowed blood vessels to restore blood flow and to avoid a heart attack or stroke and to treat brain aneurysms. An accurate surface control is needed to assure the cytocompatibility of the chosen alloy with its biologic environment. Metallic stents must satisfy precise conditions defined according to their final application. They need to respect strict requirements, in terms of mechanical properties, electrochemical interaction (corrosion) and cytocompatibility. The following alloys are traditionally used in biomedical applications and more precisely for cardiovascular applications: the alloy AISI316L is considered a reference in this field, but the alloy L605, a Co-based material, is gaining more and more importance, due to its high mechanical properties (high ductility and high ultimate tensile strength) and high corrosion resistance. The use of Titanium alloys is the new frontier for biomaterials in cardiovascular applications, it is considered as a new potential candidate for cardiovascular stents. Titanium alloys, shows a unique combination of high strength and high ductility (ultimate tensile strength and uniform deformation higher than 1000 MPa and 30%, respectively). Electropolishing is a pre-treatment step applied to these alloys to obtain chemically homogeneous surfaces, covered with a uniform and amorphous oxide layer, generally with a very smooth roughness. This process not only makes it possible to control the physical properties of the surface, but also the chemical ones. The electropolishing process has some changeable variables, such as current, voltage, electrolytic solution and temperature of electrolyte. By controlling them, it is possible to understand and improve the surface properties. This work is aimed at studying the effects of electropolishing changeable variables (current, voltage, electrolytic solution) on surface characteristics/properties (morphology, chemical composition and wettability) of those alloys used for the manufacture of stents.
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Mendez, Julie Marie. "Characterization of Copper Electroplating and Electropolishing Processes for Semiconductor Interconnect Metallization." Case Western Reserve University School of Graduate Studies / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1244216625.
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Hung, Lie-chung. "Electropolishing of Ti-6A1-4V surgical implant alloy and its effect on corrosion behavior." Thesis, Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/20731.
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Zhao, Xin. "Electropolishing of Niobium in Sulfuric Acid-Methanol Electrolytes: Development of Hydrofluoric Acid-Free Electrolytes." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/28507.
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Niobium (Nb) has the highest superconducting transition temperature (9.2 K) of the pure metals, which makes it the most used material for the construction of superconducting radio frequency (SRF) accelerators. The performance of the accelerator is critically dependent upon the quality of Nb surface. Electropolishing (EP) in hydrofluoric acid (HF)-containing electrolytes is the currently accepted treatment process. The presence of HF is necessary for the removal of the passive oxide surface film formed in aqueous electrolytes. But HF is hazardous and must be contained without human exposure and eliminated in an environmentally appropriate manner.
In the present dissertation project, HF-Free EP of Nb was performed in sulfuric acid-methanol electrolytes. Sulfuric concentrations of 0.1 M, 0.5 M, 1 M, 2 M, and 3 M were used. Cyclic voltammetry and potential hold experiments were performed in cells of both two-electrode and three-electrode setups to evaluate the electrochemical process. The influence of electrolyte concentration, temperature, and EP duration was investigated. At room temperature, both the corrosion rate and the surface quality obtained were comparable to those currently obtained with HF-based processing. With decreasing temperature, the mean current level decreased and the surface quality improved substantially. For a desired average material removal of 100 μM, nanometer scale surface roughness was obtained under multiple conditions.
Mechanism of EP was also investigated by electrochemical impedance spectroscopy (EIS). The EIS diagram indicates the presence of a compact film during EP at mass transport controlled limiting current and a film-free surface during EP at ohmic controlled current. Transfer from a film-free surface to an anodic film precipitation with decreasing temperature was also observed. Microsmoothing is only achieved under mass transport control. Nb⁵⁺ ions are determined to be the mass transport limiting species.Ph. D.
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Nathoo, Jeeten. "Optimisation of electrolyte composition and operating parameters for the electropolishing of 304 stainless steel." Master's thesis, University of Cape Town, 2003. http://hdl.handle.net/11427/5430.
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Haider, Waseem. "Enhanced Biocompatibility of NiTi (Nitinol) Via Surface Treatment and Alloying." FIU Digital Commons, 2010. http://digitalcommons.fiu.edu/etd/177.
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It is projected that by 2020, there will be 138 million Americans over 45, the age at which the increased incidence of heart diseases is documented. Many will require stents. This multi-billion dollar industry, with over 2 million patients worldwide, 15% of whom use Nitinol stents have experienced a decline in sales recently, due in part to thrombosis. It is a sudden blood clot that forms inside stents. As a result, the Food and Drug Administration and American Heart Association are calling for a new generation of stents, new designs and different alloys that are more adaptable to the arteries. The future of Nitinol therefore depends on a better understanding of the mechanisms by which Nitinol surfaces can be rendered stable and inert. In this investigation, binary and ternary Nitinol alloys were prepared and subjected to various surface treatments such as electropolishing (EP), magnetoelectropolishing (MEP) and water boiling & passivation (W&P). In vitro corrosion tests were conducted on Nitinol alloys in accordance with ASTM F 2129-08. The metal ions released into the electrolyte during corrosion tests were measured by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). Biocompatibility was assessed by observing the growth of human umbilical vein endothelial cells (HUVEC) on the surface of Nitinol alloys. Static and dynamic immersion tests were performed by immersing the Nitinol alloys in cell culture media and measuring the amount of metal ions released in solution. Sulforhodamine B (SRB) assays were performed to elucidate the effect of metal ions on the growth of HUVEC cells. The surfaces of the alloys were studied using Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS) respectively. Finally, wettability and surface energy were measured by Contact Angle Meter, whereas surface roughness was measured by Atomic Force Microscopy (AFM). All the surface treated alloys exhibited high resistance to corrosion when compared with untreated alloys. SRB assays revealed that Ni and Cu ions exhibited greater toxicity than Cr, Ta and Ti ions on HUVEC cells. EP and MEP alloys possessed relatively smooth surfaces and some were composed of nickel oxides instead of elemental nickel as determined by XPS. MEP exhibited lowest surface energy and lowest surface roughness.
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Rotty, Chloé. "Etude de l’électropolissage d’alliages horlogers issus de fabrication additive en milieu aqueux et solvant non-conventionnel." Thesis, Bourgogne Franche-Comté, 2018. http://www.theses.fr/2018UBFCD017/document.
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Ce travail de thèse s’inscrit dans lecadre du projet « MOMEQA » dont l’objectif est le soutien à l’innovation dans l’industrie horlogère en Franche-Comté. La première impression visuelle conditionne notre relation à l’objet, c’est pourquoi une finition soignée est primordiale. L’électropolissage est un procédéde dissolution électrochimique permettant der éduire la rugosité de surface d’un objet. La pièce traitée constitue l’anode dans une cellule d’électrolyse. La première partie de l’étude est consacrée aux laitons et à l’acier inoxydable 316 L. Une étude électrochimique préliminaire a permis de définir les conditions optimales d’électropolissage pour chaque matériau et milieu. La suite de l’étude a été dédiée à l’étude des comportements des aciers inoxydables 316L de fonderie comme de fabrication additive, afin de mettre en évidence l’influence du procédé de fabrication sur l’aptitude à l’électropolissage. Un dispositif spécialement conçu a également permis de faire varier les conditions hydrodynamiques et d’appliquer des ultrasons,en vue d’optimiser l’agitation. L’obtention d’une finition poli miroir sur des carrures de montres a validé la conception du pilote. Enfin, l’usage d’un électrolyte moins nocif que les mélanges d’acides, le Deep Eutectic Solvent constitué d’un mélange de chlorure de choline et d’éthylène glycol se montre prometteur. L’utilisation de ces olvant non-conventionnel permet d’utiliser des techniques d’analyses de surface impraticables in-situ en milieu très corrosif, tel que l’AFM. Finalement, un modèle décrivant les mécanismes d’électropolissage de l’acier inoxydable 316 L dans les deux milieux a été proposé, qui permet une bonne simulation des résultats de spectroscopie d’impédance électrochimiqueThis work is part of the project"MOMEQA" whose main purpose is to supportinnovation in watchmaking industry in Franche-Comté. For high-end pieces, the first visualimpression is crucial and that is why a neatfinishing is required. This is achieved byelectropolishing, which consists in anelectrochemical dissolution process that enablessurface roughness reduction. Although it ispresent in several applications, fundamentalmechanisms of electrochemical polishingremain poorly understood and tailoring theprocess to additive manufacturing parts is in itsearly stages. The first part of the study isdedicated to brass and 316L stainless steel.Basic electrolytic baths (H3PO4 for brasses anda H3PO4/ H2SO4 mixture for 316L stainlesssteel) are used as references. A preliminaryelectrochemical study allows the determinationof optimal electropolishing conditions for eachmaterial and medium. A special attention hasbeen paid to characterization methods, such asmicro-roughness, brightness, microstructure,texture and corrosion resistance. Subsequently,the study was restricted to both cast and additivemanufacturing 316L stainless steels, in order toidentify the influence of manufacturing processon the electropolishing ability. To meet theproject requirements, a pilot cell dedicated tolarge area parts was designed and built. The aimwas to study the scale-up as well as the effectsof workpieces shape. The outcome of this studywas the realization of a mirror finish on a watchdial, allowing validation of the pilot-cell design.The last part of our study consists in replicatingthe process in a less harmful electrolyte, a greensolvent (Deep Eutectic Solvent), made by amixture of choline chloride and ethylene glycol.This allows successful electropolishing,compatible with an industrial application.Moreover, it makes possible in-situ AFMmeasurements, impossible in highly corrosiveelectrolytes. Finally, a model forelectropolishing mechanism in the case of 316Lstainless steel was proposed for both media,allowing a good simulation of electrochemicalimpedance spectroscopy behaviour
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Čermák, Jan. "Návrh automatizovaného procesu elektrolytického leštění vzorků pro elektronový mikroskop." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-444286.
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This diploma thesis deals with the automation of the electropolishing process, which is per-former as the last step in the preparation of metallographic samples intended for observation in an electron microscope. A complete hardware design of a single-purpose machine has been developed, which provides the automatic preperation of up to six samples per insertion. There was the design of a manipulator for sample handling together with chemically re-sistant sample holder suitable for automatic operation as a part of solution. The design of the whole machine was developed with regard to the safety of the operator. The thesis includes detailed 3D model of the device and the desing of an application for measurement in the LabVIEW. It describes the future working process of the machine, including a description of a software for controlling the machine and sending process data of each sample to the to the database in accordance with the principles of industry 4.0. In the conclusion, the achieved results and the proposal of further steps necessary for the realization of the machine are for-mulated.
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Rodriguez, Julymar. "Étude des mécanismes d’électropolissage dédiée aux alliages d’or 18 carats en milieux aqueux et solvants eutectiques profonds." Electronic Thesis or Diss., Bourgogne Franche-Comté, 2024. http://www.theses.fr/2024UBFCD074.
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Le polissage électrochimique aussi appelé électropolissage (EP) est un procédé électrolytique de parachèvement des objets métalliques qui vise à améliorer leurs propriétés esthétiques et fonctionnelles. Sa spécificité réside dans la dissolution anodique contrôlée d’une fine couche de surface, dirigée préférentiellement sur les micro-aspérités, qui permet d’aboutir en une seule étape non seulement au nivellement de la pièce traitée mais aussi à son brillantage. C’est donc un procédé que l’on peut qualifier de super-finition permettant, en quelques minutes, d’atteindre une rugosité sub-micrométrique associée à la brillance de la pièce. Contrairement aux techniques de finition mécaniques traditionnelles (usinage, rodage, polissage…) c’est un procédé sans contact et donc sans perturbation métallurgique de la couche superficielle obtenue après enlèvement de matière. Il ne nécessite pas d’outils et s’adapte facilement aux pièces de géométrie complexes et aux structures fines en treillis.Connu depuis près d’un siècle, son application au traitement des métaux précieux est en revanche assez marginale et la bibliographie dédiée à l’électropolissage de l’or et de ses alliages est extrêmement pauvre. Ceci s’explique par le fait que les mécanismes mis en jeux ne sont pas complètement investigués et qu’en l’absence de modélisation prédictive, il est nécessaire de déterminer expérimentalement, pour chaque alliage, une formulation d’électrolyte adaptée et des paramètres électriques de traitement (en tension ou courant). Les électrolytes de polissage sont en général constitués de composés dangereux ou toxiques (fluorure, perchlorate, cyanure, cyanate, thiourée …). Ainsi la dangerosité des bains et la complexité apparente de la technique sont un frein au développement d’opérations industrielles dans les secteurs de l’horlogerie, de la joaillerie ou du luxe en général, pourtant désireux d’automatiser les procédés de finitions, en particulier pour les designs complexes. Le projet de recherche aura donc pour objectif d’étudier et de proposer un procédé soutenable d’électropolissage pour l’or et ses alliages (jaune, rose, gris, …) en rupture avec les travaux précédents du laboratoire sur l’électropolissage de métaux à haute résistance mécanique réalisé par dissolution dans des mélanges acides. Une attention particulière sera portée à la compréhension des mécanismes au regard des caractéristiques métallurgiques, topographiques et géométriques des substrats, avec une étude de la densité spectrale de puissance des motifs de rugosité. L’un des verrous scientifiques majeur à lever sera la recherche de solutions de polissage ayant un impact environnemental le plus réduit possible (exemptes de composés dangereux ou pathogènes tels que fluorure, cyanure, thiourée, …) en utilisant une large gamme de complexants combinés à l’emploi d’ondes de polarisation pulsées, de fréquence et amplitude variables. Cette analyse de la réponse du système constituera un enjeu majeur dans le potentiel d’exploitation futur des procédés développésElectrochemical polishing, commonly referred to as electropolishing (EP), is an electrolytic process used to enhance the aesthetic and functional properties of metallic surfaces. This process involves the controlled anodic dissolution of a thin surface layer, with a focus on removing micro-asperities, resulting in simultaneous surface leveling and brightening. Within just a few minutes, electropolishing achieves sub-micrometric roughness and a bright, smooth finish. Unlike traditional mechanical finishing methods such as machining, lapping, or polishing, EP is a non-contact process that preserves the metallurgical integrity of the surface. Additionally, it can be easily applied to parts with intricate geometries or delicate lattice structures, making it highly adaptable for complex applications.Known for almost a century, its application to the treatment of precious metals is however rather marginal, with very limited research dedicated to the electropolishing of gold and its alloys. This gap in literature stems from the incomplete understanding of the underlying mechanisms and the lack of predictive models. As a result, optimizing the electrolyte composition and electrical parameters (such as voltage or current) for each specific alloy requires extensive experimental work. Furthermore, the electrolytes commonly used in electropolishing often contain toxic or hazardous chemicals—such as fluoride, perchlorate, cyanide, cyanate, and thiourea—posing significant safety and environmental concerns. These factors, combined with the perceived complexity of the technique, have hindered its widespread industrial adoption, particularly in sectors like watchmaking, jewelry, and luxury goods, where gold and its alloys are prevalent.The objective of the research project will therefore be to study and propose a sustainable electropolishing process for gold and its alloys (yellow, pink, gray, etc.). Particular attention will be paid to understanding the underlying mechanisms of electropolishing in relation to the metallurgical, topographic, and geometric characteristics of the substrates. This will involve studying the power spectral density (PSD) of the surface roughness patterns to gain deeper insights. One of the major scientific obstacles will be the development of environmentally friendly polishing electrolytes. The goal is to eliminate hazardous compounds commonly found in traditional electrolytes, such as fluoride, cyanide, and thiourea, and replace them with more sustainable complexing agents. In tandem, the project will explore the use of pulsed polarization waves with variable frequency and amplitude to optimize the polishing process. This analysis of the system response will be a major issue in the future potential exploitation of the developed processes
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Mammei, Russell Rene. "Thin Films for the Transport of Polarized Ultracold Neutrons for Fundamental Symmetry Study." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/28714.
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The use of ultracold neutrons (UCN) to study fundamental parameters such as the neutron lifetime and decay correlations in polarized neutron beta decay are poised to make significant contributions to our understand of the Standard Model and its extensions. To this end, the UCNA experiment is pursuing a precision measurement (0.2%) of the angular correlation between the neutron spin and the direction of emission of the electron in polarized neutron decay (the ``A'' asymmetry). The UCNA experiment makes use of the spallation-driven solid deuterium (SD2) UCN source at the Los Alamos Neutron Science Center (LANSCE). The UCN leave the source and are 100% polarized by passing through a strong magnetic field before their decay is observed by a very sensitive electron spectrometer.
UCN guides facilitate the transfer of UCN from the source to the spectrometer. Common guide materials include stainless steel, copper, aluminum, and quartz. Often a thin film is applied to these components to increase their ability to transport/bottle and preserve the polarization of UCN. In the region of the SD2 UCN source, nickel-58 films are applied, whereas once the UCN are polarized, diamond-like carbon (DLC) films are employed. This dissertation covers the application, process developments, and characterization of these coatings. In addition a study concerning the surface finish resulting from the mechanical polishing and electropolishing of the guides that make up the UCNA beamline is presented.
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Eriksson, Alice. "Vatten- och kemikaliebesparande åtgärder samt reningstekniker inom ytbehandlingsindustrin : En studie av sköljvattenflödet på Calamo AB." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-73298.
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Denna studie har utförts på Calamo AB som arbetar med elektropolering och betning av rostfritt stål. Efter ytbehandlingssteget krävs sköljning av godset för att avlägsna kemikalierester vilket medför att stora mängder surt sköljvatten uppstår. Idag används våtkemisk fällningsanläggning för att rena sköljvattnet. Det befintliga reningsverket kräver flertalet tillsatser samtidigt som mängden slam som går till deponi är stor. Företaget vill utreda miljönyttan med att installera en vakuumindunstare för att ersätta det befintliga reningsverket som reningsmetod samt se över möjligheten att minska sin vattenförbrukning i samband med sköljning av gods för att bland annat kunna reducera storleken på indunstaren, minska belastningen på reningsstegen samt reducera mängden avfall. Studiens mål var att kartlägga uppkomsten av förorenat sköljvatten, identifiera potentiella vattenbesparande åtgärder och hur dessa åtgärder påverkar effektiviteten hos reningsanläggningarna. Samt visa hur installation av en vakuumindunstare förändrar företagets miljöpåverkan och utreda om det finns möjligheter att återanvända eller återvinna kemikalier och metaller från processen. Kartläggning och flödesmätningar av sköljvattenbehovet utfördes med hjälp av information av personal på Calamo samt en ultraljudsmätare. Vattenbesparande åtgärder, påverkan på reningsanläggning samt möjligheter till återvinning av kemikalier undersöktes genom litteraturstudie samt modellering i Excel. Utredningen av miljönyttan genom att ersätta befintligt reningsverk med vakuumindunstare utfördes med hjälp av LCA-värden hämtade från databasen SimaPro 8.0.4. Flera olika förslag på vattenbesparande åtgärder studerades och dessa gav en total vattenreduktion till reningsverket på mellan 5 - 81 % beroende på hur många samt vilka åtgärder som vidtogs. Enligt miljöberäkningarna genererar vakuumindunstaren 3 gånger högre utsläpp av koldioxidekvivalenter och 7 gånger större behov av icke förnyelsebar energi jämfört med det befintliga reningsverket. Genom att installera sprutskölj med motströmsteknik i stycke, sammankoppla befintliga sköljkar i avdelningarna betning, AVFKA samt automaten och installera sparsköljstank i alla avdelningar uppnås en reduktion av förorenat vatten till reningsstegen på 81%, vilket ytterligare kan optimeras genom installation av jonbytare, återanvändning av varmt vatten från renrum. Dessutom ökar föroreningshalten med 61% då dessa åtgärder vidtas vilket gynnar reningseffektiviteten i reningsanläggningarna och därav rekommenderas detta alternativ. Även kemikalieanvändningen och förluster av metalljoner reduceras avsevärt i processen genom användningen av sparskölj. Att installera vakuumindunstare rekommenderas inte på grund av dess stora energianvändning, dock kan andra resultat uppstå då andra LCA-värden används samt genom andra antaganden och hänsyn till kemikalie- och metallåtervinning istället för deponi.This study has been carried out at Calamo AB, which works with electropolishing and pickling of stainless steel. After the surface treatment step, rinsing of the material is required to remove chemical residues, which results in large amounts of acid rinse water. Today, wet chemical precipitation plant is used to clean the rinse water. The existing treatment plant requires most additives, while the amount of sludge that goes to landfill is large. The company wants to investigate the environmental benefits of installing a vacuum evaporator to replace the existing sewage treatment plant as a purification method and to review the possibility of reducing its water consumption in connection with rinsing of goods in order to reduce the size of the evaporator, reduce the load on the purification steps and reduce the amount of waste. The aim of the study was to map the emergence of polluted rinse water, identify potential water-saving measures and how these measures affect the efficiency of the treatment plants. And show how the installation of a vacuum evaporator changes the company's environmental impact and investigate whether there are opportunities to reuse or recycle chemicals and metals from the process. Mapping and flow measurements of the rinse water requirement were performed using information from staff at Calamo and an ultrasonic meter. Water-saving measures, impact on treatment plant and opportunities for recycling of chemicals were investigated through literature study and modeling in Excel. The study of the environmental benefits by replacing existing treatment plants with vacuum evaporators was carried out using LCA values obtained from the database SimaPro 8.0.4. Several different proposals for water-saving measures were studied and these gave a total water reduction to the treatment plant of between 5 - 81% depending on how many and what measures were taken. According to the environmental calculations, the vacuum evaporator generates 3 times higher emissions of carbon dioxide equivalents and 7 times the need for non-renewable energy compared to the existing treatment plant. By installing spray rinse with countercurrent technology in one piece, interconnecting existing rinses in the cuttings departments, AVFKA as well as the dispenser and installing sparse rinse tank in all departments, a reduction of contaminated water to the purification steps of 81% is achieved, which can be further optimized by installation of ion exchangers, reuse of hot water from clean room. In addition, the pollutant content increases by 61% as these measures are taken, which favors the purification efficiency of the treatment plants and hence this option is recommended. The use of chemicals and losses of metal ions are also considerably reduced in the process through the use of savings rinses. Installing vacuum evaporators is not recommended due to its large energy use, however, other results may arise when other LCA values are used, as well as through other assumptions and considerations for chemical and metal recycling instead of landfill.
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Valenti, Patrick. "Conception et mise en oeuvre d'un procédé de polissage électrolytique de tubes en acier inoxydable austénitique." Grenoble INPG, 1992. http://www.theses.fr/1992INPG0120.
Full textAbstract:
L'objectif de cette etude est d'aboutir a la conception et a la mise en uvre d'un pilote pre industriel de polissage electrolytique de l'interieur de tubes en acier inoxydable austenitique, dans un melange eau, ether monobutylique de l'ethylene glycol, acide perchlorique. Ce procede, consistant en la dissolution anodique d'une faible epaisseur du metal, permet d'attenuer la rugosite de la surface qui devient ainsi tres peu sujette aux phenomenes d'adsorption-desorption. Dans le cas des aciers inoxydables, il mene a la formation, en surface, d'une couche d'oxyde de chrome bien plus importante que la couche naturellement formee au contact de l'air ce qui renforce l'effet de resistance a la corrosion. L'analyse thermique differentielle de l'electrolyte montre que celui-ci est stable pour les temperatures inferieures ou egales a 100c et ne presente pas de danger particulier. Une utilisation a l'echelle industrielle est donc possible. Il a ete verifie par une etude cinetique sur electrode a disque tournant que, conformement aux donnees de la litterature concernant d'autres couples metal/electrolyte, le systeme etudie est limite cinetiquement par le transport de matiere. Il semble que le transport des cations metalliques dissous vers la solution soit le phenomene limitant mais l'hypothese d'une limitation par le transport des molecules d'eau vers l'electrode n'a pu etre ecartee de maniere indiscutable. L'etude des phenomenes hydrodynamiques lies a la production de gaz montre que, si la fraction volumique de gaz reste suffisamment faible pour que l'ecoulement du gaz ne perturbe pas l'etablissement de la couche visqueuse, l'electrolyseur, constitue par le materiau a polir et la contre electrode, se comporte comme un reacteur a ecoulement laminaire classique et peut donc etre dimensionne de la meme maniere moyennant la prise en compte des variations de vitesse et de diametre hydraulique du liquide imposes par la production de gaz. Enfin, un pilote dont la conception est basee sur le deplacement relatif de la cathode par rapport au tube et la rotation de celui-ci par rapport a son axe longitudinal, et permettant de polir des tubes de longueur 1 m et de diametre 6. 10#-#3 m a ete mis en uvre
15
Purushottam, Raj Purohit Ravi Raj Purohit. "Understanding mechanical size effects in metallic microwires : synergy between experiment and simulation." Thesis, Poitiers, 2018. http://www.theses.fr/2018POIT2290/document.
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Les microfils métalliques polycristallins produits par étirage à froid présentent une résistance mécanique significative en faisant des candidats idéaux pour les renforts de composites. Des études antérieures sur des fils de nickel polycristallin pur ont montré une dépendance importante par rapport à la taille de la limite d'élasticité et de la résistance à la traction, ainsi que de la ductilité.Le but de cette étude est de comprendre cet effet de la taille dans les microfils de nickel pur polycristallin par analyse de diffraction des rayons X in-situ (DRX) et simulations de la plasticité cristalline par éléments finis (CPFE). Des essais de traction monotone et cyclique in-situ sous rayonnement synchrotron ont été réalisés sur des microfils de diamètres allant de 100 à 40 μm. Les fils étirés à 100 micromètres obtenus dans le commerce présentent une architecture cœur-coquille avec une texture de fibre <111> dominante dans le cœur et une texture à double fibre hétérogène <111> et <100> dans la coquille. La réduction de la taille de l'échantillon par polissage électrolytique conduit à des fils ayant une microstructure homogène, tandis que la réduction de la taille de l'échantillon par un étirage à froid supplémentaire conduit à des fils avec une texture plus intense tout en conservant l'architecture cœur-coquille.La limite d'élasticité et la résistance à la traction des fils électropolis augmentent avec la diminution du diamètre, tandis que la ductilité diminue avec la réduction du diamètre. Dans le cas des fils étirés à froid, on observe que la limite d'élasticité et la résistance à la traction, ainsi que la ductilité, augmentent avec la diminution du diamètre. L'analyse DRX indique une plasticité successive des familles de grains sous iso-déformation. Nous avons observé que le gradient de la texture du microfil active des mécanismes de déformation qui ne sont pas observés pour les microfils à texture homogène. Pour comprendre l'influence de différents paramètres microstructuraux, notamment l'influence de la texture cristallographique, une microstructure représentative 3D a été générée et des simulations CPFE ont été réalisées. Le comportement simulé moyen des différentes familles de grains (<111>, <100>) concorde bien avec les résultats expérimentaux. La simulation CPFE indique une hétérogénéité du champ de contrainte à travers la microstructure en présence d'un gradient de texture cristallographique.Nous montrons que la micro-texture (texture simple ou double texture) et leur dispersion spatiale (homogène ou architecturée) peuvent être utilisées comme stratégie de conception pour obtenir une microstructure optimale en fonction de l’ensemble désiré de propriétés mécaniquesPolycrystalline metallic microwires produced by cold-drawing exhibit significant mechanical strength that make them ideal candidates for reinforcement of composites. Previous studies on polycrystalline pure nickel wires have indicated a significant size dependence of their yield and tensile strength as well as their ductility. The aim of this study is to understand these size effects by in-situ X-ray diffraction (XRD) analysis and crystal plasticity finite element (CPFE) simulations. In-situ monotonous and cyclic tensile tests under synchrotron radiation were carried on microwires with diameters ranging from 100 to 40 µm. The commercially obtained 100µm as-drawn wires exhibit a core-shell architecture with <111> fiber texture dominant in core and heterogeneous dual fiber texture <111> and <100> in the shell. Reduction of specimen size by electropolishing leads to wires having a homogeneous microstructure, whereas reduction of specimen size by further cold drawing leads to wires with a sharper texture while retaining the core-shell architecture.The yield and tensile strength of the electropolished wires increase with decreasing diameter, whereas the ductility decrease with decreasing diameter. In the case of cold-drawn wires, the yield and tensile strength, and also the ductility was observed to increase with decreasing diameter. The XRD analysis indicates successive yielding of grain families under iso-strain condition. The gradient in the texture of the microwire was seen to activate deformation mechanisms which are not seen for microwires with homogeneous texture. To understand the influence of different microstructural parameters, and notably the influence of crystallographic texture, 3D representative microstructure was generated and CPFE simulations were carried out. The simulated average behavior of different grain families (<111>, <100>) agrees well with the experimental results. The CPFE simulations indicate heterogeneity in stress field across the microstructure in the presence of a gradient in crystallographic texture.We show that the microstructure engineering of micro-texture components (single- or dual-texture) and their spatial spread (homogenous or architectured) can be used as design guidelines for obtaining optimal microstructure in accordance with desired set of mechanical properties
16
Saas, Jean-Noël. "Étude et mise au point de nouveaux électrolytes en vue d'effectuer en électropolissage d'alliages utilisés dans les centrales nucléaires : application à la décontamination électrochimique." Grenoble INPG, 1996. http://www.theses.fr/1996INPG0179.
Full textAbstract:
Dans l'industrie nucleaire, l'electropolissage est une methode de preparation des surfaces metalliques qui permet de limiter la corrosion, de diminuer la retention des particules contaminees et de faciliter les operations de maintenance. La surface est lisse et brillante. Cette technique peut aussi etre utilisee en decontamination. L'objectif de ce travail est de mettre au point un electrolyte pour l'electropolissage et la decontamination de l'inconel 600 et de differentes nuances d'aciers inoxydables (aisi 304l, 306l, 308l). Les effluents de decontamination doivent conduire a un volume minimum de dechets secondaires. Ce travail presente, dans un premier temps, le choix des constituants (acide nitrique et acide hydroxyacetique) et l'optimisation de la composition de l'electrolyte par la methodologie de la recherche experimentale. Un plan des melanges a permis de modeliser l'effet de la composition du melange sur la vitesse de polissage, l'etat de surface des echantillons, la stabilite chimique de l'electrolyte. L'analyse des phenomenes de transport dans la couche visqueuse a ete realisee pour l'electropolissage de l'inconel 600 grace a des techniques electrochimiques (electrode a disque tournant, impedances), des techniques d'analyse de surface (spectroscopies auger et raman, microscopie electronique a balayage, profilometrie et brillancemetrie) et l'isolement et la caracterisation de la couche visqueuse. Le polissage resulte d'un phenomene physique dans lequel il n'y a pas de precipitation de sels metalliques a l'interface metal-electrolyte. Le polissage serait du a l'appauvrissement en eau a la surface. L'acide hydroxyacetique n'intervient que pour ses proprietes viscosantes et les ions nitriques par leurs proprietes physico-chimiques vis a vis de la surface. La deuxieme partie de ce travail a consiste a valider les resultats sur un pilote de laboratoire developpe dans le cadre de cette etude. Cet electrolyte a permis de decontaminer des echantillons radioactifs provenant de centrales nucleaires. Les resultats de decontamination ainsi que les etats de surface apres polissage electrochimique sont analogues a ceux obtenus avec les meilleurs electrolytes utilises jusqu'a present. Le traitement des effluents propose est le suivant: oxydation de l'acide hydroxyacetique en co2 et distillation de l'acide nitrique qui pourra etre reutilise
17
Wang, Chong-Hsing, and 王忠祥. "The Effects of Forced Convection on ElectroPolishing." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/13094230271687630516.
Full textAbstract:
碩士元智大學
機械工程學系
92
The ElectroPolishing process without external agitation exhibits the characteristics of unstable current density, uneven and more severe surface defects, decreased process efficiency and difficulties in process control and quality management. The forced convection is one of the most effective and direct methods in improving above problems. Currently, these mechanisms of forced convection include Rotating Disk Electrode (RDE), pulse current and mechanical agitation motions. In this research, the external injection flow of electrolyte was employed to control the forced convection phenomena. The experimental works were conducted to study the effects of flow velocity and electrode gap on process parameters such as I-V curves, variation of current density and variation in bubble layer and quality of processed workpiece such surface roughness, surface shine and pitting. In addition, the fluid parameters of density and viscosity of both the electrolyte and viscous layer were measured in order to facilitate numerical simulation. Numerical analyses with respect to three levels of flow velocity and electrode gap were simulated by the FEMLAB software. These numerical results were compared with experimental measurements to verify the effects of the forced convection on ElectroPolishing process. Under the conditions of incompressible and laminar flow, the conclusions were as followed: 1.When the flow velocity is too fast, the viscous layer may be destroyed or disbursed. The favorable effects of EP process dismissed. Therefore, the forced convection mechanism should be conducted under the pre-condition of not destroying the viscous layer. 2.The forced convection increases mass transfer phenomena and therefore, improves the process efficiency and stability, increase current density and decrease surface defects. 3.Because of the impact of flow at the inlet, velocity profile exhibits component of velocity field perpendicular to the electrode. The surface quality thus was affected. 4.Within the experimental parameter of electrode gap ranging from 10 mm to 15 mm, the difference in velocity fields near the electrodes were small. The results of EP process were similar. Thus, it does not have significant effect on the EP process.
18
Shih, Po-Chung, and 施博中. "The Effects of Pulse Current on ElectroPolishing." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/84435984971499795044.
Full textAbstract:
碩士元智大學
機械工程學系
93
ElectroPolishing is an electrochemical anodic dissolution process. Many process parameters may affect the final quality. The bubbles of hydrogen and oxygen on the electrodes, especially on the anode, have the most impact on surface quality of the specimen. Bubbles on the anode may tick to the anode resulting surface defects such pitting hole and flow marks. The bubbles in the electrolyte may also create electrical resistance and non-uniform electric field distribution. In this research, the effects of pulse current supply on electropolishing process were studied. During the time-on period of the pulse current, electrochemical reaction took place near the electrodes creating ionic concentration difference. During the time-off period, the ions in the electrolyte may replenish by diffusion and convection. The reactant and bubbles may also have time to escape. The process may be more stable. The specimen material was SS316L stainless steel. The experimental variables were pulse width, duty cycle, electrode gap and polishing time. Surface indices such as surface roughness and microscopy photo were used to evaluate their effects. Summing up the results, the application of pulse current can get the good surface qualitiy than direct current indeed.
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Teixeira, Alexandre. "Development of an Electropolishing Method for Titanium Materials." Thesis, 2011. http://spectrum.library.concordia.ca/7619/1/Teixeira_MASc_S2011.pdf.
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Lai, Jian-Jang, and 賴建璋. "The Investigation of Electropolishing Technique for stainless Steel Surface." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/23820649549939756913.
Full textAbstract:
碩士元智大學
機械工程學系
90
The ElectroPolishing(EP) process is emerging as one of the key technology for the manufacturing of components of the semi-conductor and bio-medical industries due to the requirement of highly smooth, clean and corrosion resistance on the component surfaces. At present, the major compositions of the electrolyte used in the EP process are sulfuric acid and phosphoric acid. However, the mechanisms between the electrolytic constituents and the anti-corrosion capability of the component surface after processed are not fully understood. It has been one of the technological bottlenecks to proliferate this technology. Therefore, it is the focus of this paper to perform a systematic study on the relationship between electrolytic constituents and its anti-corrosion capability to the component surface. SS 316 stainless steel plates were employed as both anode and cathode metal plates. The electrolyte was composed of sulfuric acid, phosphoric acid, additive and DI water. They were formed into two groups to study the ratios of concentration level between sulfuric acid and phosphoric acid and that between additive and DI water on the forming mechanism of passive film. It was also to study the effect of passive film on corrosion resistance. Experiments were first conducted to investigate I-V curves of various concentration levels of the electrolyte to find out the “plateau” areas that are conditions suited for electropolishing. Detailed experiments were followed using current density as control parameter in order to find out the optimum operating current density and voltage. Finally, time-history experiments were conducted for various electrolyte components to record thickness of passive films vs. time. The test specimens were analyzed for its anti-corrosion capability and compositions of the passive film. ESCA instrument was employed to analyze the composition of the passive film and to estimate its thickness. From these results, the relationship of the electrolytic constituents, vs. under the optimum operating conditions, the composition and thickness of the passive film and the anti-corrosion capability can be established. Using the SEMI standards as guidelines, an electrolyte that uses much lower concentration level of the sulfuric acid and operates under lower temperature was derived from the experimental results. It is saved to operate and meets all the SEMI specification requirements.
21
Chih-Chang, Huang, and 黃志昌. "Investigation of Copper Electropolishing for Damascene Interconnects in ULSI." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/73398810131510747649.
Full textAbstract:
碩士國立交通大學
材料科學與工程系
90
The purpose of this thesis is to establish Cu electropolishing technology for the back-end multi-layer interconnects, including the production of copper wires by electropolishing process, the planarization of step-height for Cu electroplating layers and the pattern effects on Cu electropolishing. The main issue for the requirement of planarization and reliability is the development of the electropolishing electrolyte and the optimum of operation parameters. In tradition, electropolishing is the important technology of surface treatment. It can dissolve metallic film uniformly and produce a smooth and bright surface. In electropolishing processes, the composition of an electropolishing and operation parameters are the key points affecting the capability of the planarization. The challenge for electropolishing being a technology of globe planarization in sub-micron copper interconnects is how to develop an effective electropolishing electrolyte and proper additives. In sub-micron semiconductor interconnects, chemical-mechanical polishing (CMP) is one candidate technology for global planarization. However, mechanic stress, waste stream, scratches, and post-CMP clean are critical problems in CMP applications. Therefore, we could utilize the electropolishing technology to improve the performance for CMP of electroplated copper. For example, in the typical two-steps Cu-CMP processes, we can employ electropolishing technology as the first-step CMP to eliminate scratches produced by CMP slurry and then improve the planarization capability of CMP. In this study, citric acid was added into the electrolyte as additives in order to further improve the planarization efficiency of Cu electropolishing. With the few additives producing a diffusion gradient on the step-height surface of Cu films, those local acidities and conductivities at the recess and protrusion between inside and outside of the trenches will change. Furthermore, the capability of step-height reduction on Cu electropolishing will improve. Besides, The polyethylene glycol (PEG) was also employed to suppress the pitting resulting from the production of Oxygen bubbles at highly operation voltages on Cu electropolishing; then a smooth and bright surface of Cu films would be accomplished due to the better wetting ability of PEG. In the future, we could furthermore integrate copper electropolishing with non-barrier low-dielectric materials (non-barrier low-k materials) to replace CMP processes. Since uniformly dissolved copper film is intrinsic characteristic of electropolishing, the problems of removal selectivity between copper film and barrier film, oxide erosion, and post-CMP clean could be disappeared naturally. As we mentioned above, the throughput will become higher.
22
Parra, Jose Leonardo. "Pitting corrosion during the electropolishing of austenitic stainless steels." 1986. http://catalog.hathitrust.org/api/volumes/oclc/15496403.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 1986.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 68-69).
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Lai, Jian-Jang, and 賴建璋. "The study of the electropolishing mechanism on SS316 satinless steel." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/35919953007155727417.
Full textAbstract:
博士元智大學
機械工程學系
95
The electropolishing(EP) is a surface finishing treatment technique. The surface quality indices such as surface roughness, cleanness and corrosion resistance could be improved through this process. Therefore, the electropolishing process was widely used to fabricate high cleanness apparatus for semiconductor optical and pharmaceutical industries. The electropolishing is an electrochemical process. The uniform and stable viscous layer was the key mechanism in enhancing the surface quality. The forming of viscous layer was influenced by the current distribution, gas bubble, fluid field and diffusion phenomena. Therefore, undesirable topology such as pitting, flow marks and scrape could be found after the electropolishing process which also reduces geometrical precision. This study is foci on numerical simulation and experimental measurement of the EP process. A numerical simulation model is established with process variables of operating potential, electrode area ratio, electrode geometry and electrode gap to simulate the iron concentration distribution on the surface of specimen. Based on the simulated results, proper process variables were chosen to conduct the EP experiments. From the experiments, profiles of the original and processed specimen were then measured by surface profile scanning machine to verify the simulation results. It could establish a relationship between iron concentration and metal removal. The results showed that the simulated iron concentration distribution data did emulate the topological contour. In this study, the surface topological and chemical properties were also studied. The indices such as surface roughness and defects were employed to evaluate the surface topological properties. The corrosion resistance such as uniform corrosion, intergranular corrosion, pitting corrosion and XPS/AES were employed to evaluate the passive film properties. The optical surface defects analysis exhibits good capabilities of high sensitivity, wider range of measurement and high efficiency to identify the surface quality under different process variables. It also provides the evidence to confirm the improvement of surface quality and stability of the EP process. In summary, a new methodology has been developed which could greatly improve the stability and uniformity of the EP process. It also provides an efficient way for electrode design, optimize process parameters and save the time of try-and-error.
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Chang, Shih-Chieh, and 張世杰. "Investigation of Cu Electroplating and Electropolishing Processing for Multilevel Interconnection." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/53644342436488217197.
Full textAbstract:
博士國立交通大學
材料科學與工程系
91
Electroplating (ECP) has been the leading method for Damascene Cu deposition in multilevel interconnection due to its low cost, high throughput and superior gap-filling capability. To achieve defect-free filling in sub-0.2 m trenches/vias, various plating baths and process conditions are investigated in the literatures. Precisely control of Cu ECP is both essential and difficult. Defect-free filling is usually obtained at a rigidly process window. Furthermore the plating chemistries are too complicated to predict and control because they are usually proprietary and they may cleave, decay and co-react during Cu ECP. Further studies are needed to realize the electrochemical behaviors of Cu ECP. In this thesis, polarization, organic additives, post-ECP annealing and pulse current of Cu ECP are studied to optimize the film properties and gap-filling capabilities. For next technology node, super-low-k dielectrics (k<3) will be adopted in the Cu Damascene process to reduce RC delay of interconnect. However, integrating new materials would face with many process challenges. In particular, low-k dielectrics with porous structure would be mechanically weaker than silicon dioxide. Typically chemical mechanical polishing (CMP) processes will cause sever damage on low-k films. Cu electropolishing (EP) is recently explored as a replacement of Cu-CMP. An applied electric field is substituted for the mechanical force component in CMP to remove excess Cu layers. The stress-free characteristic of Cu EP can handle low-k dielectrics. Furthermore, Cu EP has the advantages of high polishing rate, low waste stream, no abrasive and no scratching. It can produce a clean and scratch-free Cu surface. In this thesis, the electrochemical behaviors and micro-leveling mechanism of Cu EP are studied. Organic acid additives are also used to achieve “super-polishing” in wafer processing.
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Cai, Zhen-Yu, and 蔡鎮宇. "A Study of Molybdenum by Electrical Discharge Machining and Electropolishing." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/96571872733573349915.
Full textAbstract:
碩士國立中央大學
機械工程研究所
95
Molybdenum is a refractory metal characterized with high melting point、good strength、low coefficient of thermal expansion、good thermal and electrical conductivity. Although it is widely used in high temperature applications, its superior mechanical properties cause it very difficult to be machined into high quality surface on parts. The EDM is a kind of electro-thermal process which removes the material by melting and vaporization routes without directly touching the surface. This study presents an experimental investigation of the machining characteristics of molybdenum by electrical discharge machining (EDM). However as general condition after EDM, the residual microcracks and craters on surface may seriously affect the machined quality. In order to further improve the EDMed surface of molybdenum, the electropolishing (EP) treatment was taken and the effects of process parameters were also analyzed in the second part of study. Experimental results show that the polarity of EDM has a great deal effects on machining of molybdenum. Using positive polarity (+) of workpiece must apply greater energy density to remove material. But using negative polarity (-) of workpiece apply small energy can remove material. The original surface roughness of EDMed molybdenum can be improved from 0.9μm Ra and 8.5μm Rmax to 0.23μm Ra and 1.48μm Rmax, after EP process. It is evident that the EP process is an effective method to enhance the EDM surface quality by improving rate up to 74.4% Ra and 82.5% Rmax.
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Chiou, Fang-Wei, and 邱芳慰. "The mechanism of nano array on the stainless steel by electropolishing." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/75931024493854590347.
Full textAbstract:
碩士國立交通大學
材料科學與工程系
91
In this study, the nano array pattern on the commercial 304 stainless steel (FCC structure) be gotten successfully by electropolishing. And it was firstly observed the nanoscopic regular morphology on the 430 stainless steel (BCC structure). According to the results, the mechanism of nano array formation on the stainless steels does not depend on the purity or crystal structure of the substructure. Therefore, the past theories about nano array formation are discarded in this case. However, the phenomenon can be explained fully by the latest theory of the electroconvection.
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Hung, Jung-Chou, and 洪榮洲. "Study of Micro-holes Machining Using Micro-EDM Combined with Electropolishing." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/85012304866525743115.
Full textAbstract:
碩士國立中央大學
機械工程研究所
92
Abstract Micro-holes with diameter less than 100μm can be effectively fabricate by micro-EDM in micro-machining. But using micro-EDM to manufacture micro-holes on metal plate, the recast layer include micro-crack and crater was formed on the hole-wall will lead to poor surface roughness to affect quality of micro-hole seriously. For this reason, the Hymu-80 was chosen as the workpiece material in this study, using micro-EDM combined with electropolishing to machine micro-holes. It expected to improve the quality of micro-holes after EDM to satisfy the precision engineering. The results showed that, using electropolishing to machine the surface of the hole-wall could obtain obviously improvement.
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Liu, Sue-Hong, and 劉書宏. "Copper Electroplating and Electropolishing for the Application of Cu Damascene Interconnects." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/18915190632133973500.
Full textAbstract:
博士國立交通大學
材料科學與工程系所
94
There are three parts in this study. The first introduces aging influence of polyethylene glycol (PEG) and PEG- bis-3-sodiumsulfopropyl disulfide (SPS) containing bath on gaps filling during Cu electrodeposition. The second part introduces the role of alcohols and organic acids additives in electrolyte of damascene Cu electropolishing. In order to save many risks and cost at the back end of the interconnect fabrication, third part demonstrates a method that can integrate Cu electrodepostion and electropolishing in one electrolyte and electrochemical tank. The developing method can be called dual-mode plating. First part, we investigate how the degradation of poly (ethylene glycol) (PEG) additives-containing and PEG-bis-(3-sodiumsulfopropyl disulfide) (SPS)-containing Cu electroplating electrolytes influences the gaps filling of damascene features and the roughness of plated surfaces. For only PEG-containing bath, the cleavage of PEG whose reaction is enhanced by a high bias current and more plating cycles, not only diminishes the inhibition effect of the electrolytes, but also enables the formation of enormous complexes of short-chain PEG–Cu far from the reacting surfaces. Hence, the more plating cycles performed, the worse the gaps filling characteristic and the rougher the plated surfaces. Furthermore, an overshoot phenomenon on the transient cells voltage for PEG-containing electrolytes is observed and explained well by a dynamic equilibrium between PEG absorption ability and Cu reduction speed. Accordingly, the change in overshoot shape is closely related to PEG aging and this fact is employed to examine the reliability of electrolytes. Moreover, we verify the two possible mechanisms of degradation of SPS. First explanation: SPS will crack into two MPS driven by the overpotential of plating, and MPS is more active depolarization than SPS. Moreover, the more and more existed MPS will make the electrolyte more ineffective for filling capability during aging process. Second explanation is SPS will lose all the accelerating ability after becoming S product which is some kinds of derivatives of SPS. Second part, we demonstrate a two-additive electropolishing (EP) electrolytes that exhibit an extremely high planarization-efficiency in Cu damascene schemes, independent of pattern sizes (1-50 μm). This electrolyte is displayed by adding alcohols and organic acids to the H3PO4 electrolyte. The high wetting ability of alcohols allows such additives to easily access the damascene bottom. This mechanism, assisted by the reduced polishing rate associated with the high surface viscosity caused by alcohol additives, greatly passivates the damascene bottom from elecropolishing. Accordingly, the superpolishing functionality of the two-additive electrolyte outperforms additive-free and one-additive electrolyte. Furthermore, this study also explores how the dissolution of damascene Cu depends on accelerators of organic acids in alcohol-containing H3PO4 electropolishing electrolytes. Four two-additive electrolytes that contain different accelerators, acetic, citric, citrazinic, and benzoic acids, are evaluated. At the bottom of damascene features, an esterification reaction between alcohols and organic acids efficiently forms a highly resistive layer and reduces the acidity of the solution. Accordingly, outside the damascene features, the rate of removal of Cu is dominated by the acidity of electrolytes but, inside the features, it is also determined by the resistance of the viscous layer. For a weak acidic additive, acetic acid, an extremely high additive concentration is introduced to sustain the moderate acidity of the solution to initiate intense esterification. Therefore, how acetic-acid-based two-additive electrolytes exhibit excellent Cu planarization capability is realized. In third part, an effective technology (Cu dual-mode plating) containing two functions of Cu film depositing and polishing in one-step electrochemical process in one tank has been developed. We have identified chemical additives and processing parameters in dual-mode plating. By mixing inhibitors, leveler, and phosphoric acid with standard copper electroplating solution, we are able to obtain similar planarization and gap-filling performance in narrow trenches (350nm) and step-height reduction in wide trenches (50 μm) to those of standard electroplating solution with identical processing time and yield of 60%.
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Chia-YingLin and 林佳穎. "Study on Electropolishing of Stainless Steel (SUS 316L) in Presence of Surfactant." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/30511079138213357128.
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碩士國立成功大學
化學工程學系碩博士班
98
The stainless steel alloy (SUS 316L) is widely used in biomedical applications due to its characteristics for better corrosion resistance and a lower friction factor. Particularly, it is also frequently used in dental applications, such as orthodontic braces and wires. In this study, an eletropolishing process is developed to enhance the surface morphology of the SUS 316L without sacrificing its biocompatibility. The potentiostat, optical microscope, atomic force microscope (AFM), scanning electron microscope (SEM), as well as X-ray photoelectron spectroscopy (XPS) are employed to characterize the surface finish of the electropolished SUS 316L pieces. Proper dosage of surfactant is introduced in the electrolyte used in the electropolishing process to give better finish surface. Especially, the best appearance and the lowest roughness values obtained on SUS 316L finishes occur at that with 5 ppm Tergitol 15-S-9 added to the electrolyte. However, the surface roughness increases with either more or less Tergitol 15-S-9 added. From XPS analysis, the contents of Fe and Cr on the electropolished samples seem to decrease. Furthermore, the electropolishing process produces a few compounds with P and Na, such as sodium phosphate and sodium carbonate, which are benefit to the cell growth. According to the cytotoxicity test using NIH 3T3 fibroblast cells, biocompatibility is not significantly reduced on surface finish of electropolished SUS 316L pieces. However, probably owing to the lower RMS surface roughness, fewer cells attached are observed on the electropolished samples, compared to those of as-received ones.
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Chen, Hsi-Tsun, and 陳璽存. "THE STUDY OF ELECTROPOLISHING OF ALUMINUM SHEET AFTER ANODIZING AND ELECTROLYTIC COLORING." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/54973933744093905814.
Full textAbstract:
碩士大同大學
化學工程學系(所)
97
The effect of the step of electropolishing before anodic oxidation on the properties of aluminum oxide film were investigated in this study. It is expected that the addition of “electropolishing” before anodizing step can obtain a better anodic film and colored film. The experimental results show that the electropolished aluminum sheet increase the number of pores of the anodic film. And make the pores more uniform and more orderly. If electropolishing is used, the △E* value and reflectivity of the colored film are lower than without electropolishing. From corrosion test, the corrosion resistance is in the following order : (Aluminum sheet after EP) < (aluminum sheet with no EP) < (anodic film with EP) < (anodic film with no EP) < (colored film with no EP) < (colored film with EP). The optimal operating conditions for obtaining the blackest colored film are: electropolishing voltage 10Vdc, electropolishing time 30 min, anodizing current density 2A/dm2, electrolytic coloring voltage 20Vac and electrolytic coloring time 30 minutes, the lower △E value, corrosion rate and
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Zeng, Song Yu, and 曾松裕. "The electropolishing behavior of austenitic stainless steel specimens with different sulfur contents." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/32441314717019743066.
Full textAbstract:
碩士長庚大學
機械工程研究所
96
Pure stainless steel pipe fitting is applied on the process in photoelectric and semiconducting industry. Since it is used to convey the aggressive as well as noxious gas and fluid, pure stainless steel pipe fitting must be qualify for corrosion, even cause no reaction in order to make the gas and fluid pure. Undoubtedly, the requirement for quality of it will be still stricter than usual industrial pipe fitting. The electropolished pipe fitting could reach the surface to the requirement about asperity and pureness for high corrosive–proof. As far as Austenitic stainless steel is concerned, the different amount of sulfur added could generate some problems through electropolishing. High amount of sulfur (0.025wt% and above) of stainless steel would apt surface the condition of the holey when electropolished, as low amount of sulfur (0.005wt% and below) would apt the condition of better asperity. Besides, we can find there is no longer hole on the surface. After digesting the experiences and effects, to be aimed the high amount of sulfur of pure stainless steel at different kinds of solution, its micro-structure, and the analysis on properties of electrochemistry, so as to probe the effects on electropolishing in each kind of parameter of process. The effects make us recognize that each kind of electrochemistry behavior, for instance, temperature, ingredient proportion, consistency, and additive etc., and electrochemistry polishing. We could also observe the micro-structure and measure the mechanical properties so as to get the properties of electropolishing more precisely, and find the electropolishing way which is well-applied to high amount of sulfur of stainless steel. The results show that pleasingly leveling and brightening surface can be achieved, when electropolishing in 3:2 and 7:3 V/V H3PO4-H2PO4 mixed acid, additional water range from 4 to 8 vol.% with the rotation speed range from 100 to 200 rpm at 60 ℃.
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PA, PAI SHAN, and 巴白山. "A Study of Electrode Design in Electropolishing of Internal and External Cylindrical Surface." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/21696783654497068998.
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博士國立清華大學
動力機械工程學系
87
This research provides an electropolishing using low-cost electrode with high efficiency. It requires no expensive special-purpose equipment or high material removal as the conventional ECM does, it also dismisses the complex pre-polishing of workpiece in the soakage electropolishing. It offers fast improvement of the surface roughness of workpiece and is a new area in electropolishing. In order to elevate the efficiency of the electropolishing on die materials and parts, i.e. to reach the fast improvement of the surface roughness of the workpiece, so as to reduce the residual stress on the surface efficiently, the present study discusses the surface roughness of several common die materials after traditional machining, of which the internal and external cylindrical surface are electropolished by different types of electrode design. The research is expected to provide the best design of electrode, which will help widen the application in the future. For the electropolishing of internal holes, completely inserted and feeding electrodes are connected with both continuous and pulse direct current. The external electropolishing studies the design of turning tool electrode, arrow-head electrode, ring-form electrode, and disc-form electrode. The controlled factors include the diameter of the electrode, the chemical composition and the concentration of the electrolyte. The experimental parameters are electrical current density, current rating and pulse period, electrode design, die material, workpiece and electrode rotational speed, polishing time, and electrode feed rate. For the internal electropolishing, the electrode with helix discharge flute performs better than that without flute or with straight flute. The electrode of borer type performs better than that with a lip on the leading edge. Pulse direct current can improve the polishing, but the machining time and cost are increased. The electrobrightening after reaming needs quite short time to make the hole bright, while the electropolishing saves the need for reaming, making the total process time less than electrobrightening. For the external electropolishing, Smaller nose radius or end radius produces higher current density and provides faster feed rate and better polishing effect. The electrodes with large discharge flute and large flute rake angle, small taper angle, or smaller cross-section are associated with larger discharge space, thus polish better. The disc or ring electrode with pins attached on edge performs the best of external electropolishing. The fluted or pin-type electrode will be incorporated into the design for an equivalent effect of using pulse current. Ultrasonic aided electropolishing elevates the polishing effect and the machining time is not increased.
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Wu, Ming-Che, and 吳明哲. "The Optimization of ElectroPolishing on Stainless Steel Wire Rope Using Experimental Design Method." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/46354825391635236899.
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碩士南台科技大學
工業管理研究所
97
Although the domestic electro polishing technology has gradually come to maturity, the technology is mainly applied to regular-shaped mental component or sheet products. When it comes to irregular and complex-shaped object, the technology and literature can hardly be found domestically. The aim of this research is trying to probe into stainless steel wire rope. A stainless steel wire rope is braided by multiple stainless steel wires. It is renowned for its appearance, anti-corrosion, and high-tension strength as its selling points. The lubricating oil used in the production can stabilize the braiding process. However it is easily to oxidize through combining corroded substance in the environment with oxygen in the air. On the other hand, the drawing process is one of shaving deformation process. It is easily to lead to strain hardening on the surface of fine wires and to forming stress concentration which have great influence on the life time (fatigue), anti-corrosion and anti-smudging of wires. The research will search for the optimal proportions of polishing solvent by mixture experiment and then find the optimal settings of the environmental parameters for the continuous polishing machine by using Taguchi method. Finally, the research will establish a roll-to-roll electro polishing machinery for stainless steel wire as a proof of the experiment. Key words: Electro polishing, Mixture experiment, Taguchi method
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KAO, CHUN-DER, and 高崇德. "Effect of the electropolishing on the electroplating of chromium in barrel of guns." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/08677468830851428504.
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Chang, Jo Hsuan, and 張若軒. "The electropolishing behavior of copper and copper alloy in aqueous phosphoric acid solution." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/67530467522977073535.
Full textAbstract:
博士長庚大學
機械工程學系
102
The aim of this study is to investigate the electropolishing behavior of pure Cu and cartridge brass. Pure Cu specimen was electroplated on a rotating cylindrical Ti electrode in Cu-sulphate plating baths with different thiourea contents. The hardness variation, microstructures and electropolishing behavior of the Cu deposits were studied. Experimental results show that some sulphur-rich particles were identified in the Cu deposits prepared from the thiourea-containing baths. The sulphur-rich particles dissolved preferentially during electropolishing in a 40 vol.% H3PO4 solution, forming a thin amorphous phase containing P in patches on the outer surface of the Cu deposit. The Cu deposits prepared in the baths with thiourea showed higher anodic dissolution current during electropolishing and formed a brightened and levelled surface with a surface roughness (Ra) lower than 30 nm. The electropolishing behaviour of cartridge brass in a 70 vol.% H3PO4 solution was studied using a rotating disc electrode (RDE). Based on the results of an anodic polarization test, a transition peak varying from kinetic-controlled to diffusion-controlled dissolution was detected when a blue Cu2+-rich layer was developed on the RDE. The blue Cu2+-rich layer impedes the anodic dissolution rate of the brass-RDE and is essential for levelling during electropolishing. Potentiostatic polishing at different locations on the limiting-current plateau was studied. By polishing at the transition-peak potential, grain boundaries were preferentially etched. In contrast, a well-polished surface with a nanosized surface roughness (Ra) was achieved after electropolishing in the middle of the limiting-current plateau. By polishing at the end of the limiting-current plateau at a relatively low rotational speed, nipple-like and flow-streak features were observed. The formation of these features is attributed to the evolution of oxygen bubbles on the RDE surface. Mechanisms for the formation of the above-mentioned features were also proposed in this study. The electropolishing behaviour of cartridge brass in a 70 vol.% H3PO4 solution was also studied using a rotating cylinder electrode (RCE). The same results of the study with RDE, the Cu2+-rich layer is necessary for leveling the brass-RCE. The electropolishing effect on the RCE is relatively easy to achieve, because a full coverage of the Cu2+-rich layer on the RCE surface was seen during electropolishing. A rod-climbing phenomenon of the Cu2+-rich layer was observed when electropolishing the brass-RCE at a rotational speed above 100 rpm. The formation mechanism of rod-climbing was discussed and proposed in this study.
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Yang, Tsung Heng, and 楊宗衡. "A study of electropolishing behavior of commercial pure nickel in phosphoric-sulfuric mixed acids." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/44577398328054744720.
Full textAbstract:
碩士長庚大學
機械工程學系
100
The commercial pure nickel alloy (Nickel 200) has been widely used in chemical industries owing to its excellent corrosion resistance and anti-oxidation properties in high temperature environment. Generally, the surface of Nickel 200 is often polished in industrial applications. Except mechanical polishing, electropolishing is commonly used because of convenient operation and suitable for fine parts. In this study, the anodic polarization and electropolishing behavior of Nickel 200 in phosphoric-sulfuric mixed solutions with different volume ratios was studied by using rotating disc electrode. After electropolishing, the surface morphologies of Nickel 200 were examined with optical, scanning electron and atomic force microscopes. The results of polished surfaces were discussed with electropolishing parameters, such as rotation speed and solution composition. The results of anodic polarization test showed that an obvious transition from active to transpassive dissolution was found with an increasing the phosphoric acid content in the mixed acids. The limiting current density increased with an increasing the rotation speed. On the other hand, the potential range of limiting current plateau reduced apparently when the rotation speed and the phosphoric acid content. According to the results of electropolishing, three specific surface morphologies can be found namely. Furthermore, the possible formation mechanisms of these three specific surface morphologies were proposed based on experimental results. According to the AFM quantitative analyzing, the Nickel 200 could be well electropolishied at rotating speed of 200 rpm in the phosphoric-sulfuric mixed acid in a volume ratio of 2:1. Although adding water in phosphoric-sulfuric mixed acids could increase the limiting current density significantly, an excess addition of water narrowed the potential range of limiting current plateau and suppressed the brightening effect.
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Chang, Po-Chun, and 張泊鈞. "The Impact of Electropolishing Process Parameters on the Reflection Rate and Roughness of 316L Stainless Steel." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/30887990009120470780.
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碩士逢甲大學
紡織工程所
95
This study deals with a mechanism of electropolishing for 316L stainless steel with ultra mirror-like surface based on the principles of physical polishing and chemical electrolyzation. 316L stainless steel plate was employed as anode and brass as cathode. The electrolyte was composed of sodium nitrate and deionized water. The polish pad was made of ultra fine fiber artificial leather and attached to the rotational electrode for cleaning emitted bubble and grinding. The test samples of 316L stainless steel was washed and cleaned by ultrasonic cleaner before the electropolishing. The four main parameters of electrolytic concentration, fixed current, electrode rotational speed, electrolytic polish time were discussed in this study. Besides, electrolytic temperature and NaCl concentration were also discussed. The finished samples were measured for their reflection rate and roughness by Spectrophotometer and Atomic Force Microscope (AFM), respectively. The mirror-like surface and electropolishing assessments were analyzed with reflection rate under 700 nm incident light and surface roughness Ra. The optional condition in this study for the electrolytic concentration of 20 wt%, fixed current was 8 A, electrode rotational speed was 600 rpm, electrolytic polish time was 8 min, electrolytic temperature was 20 ℃and no NaCl was presented in the electrolytic solution. The reflection rate of 316L stainless steel plate was increased from 61.18 % to 66.27 %, roughness decreased from 15.3 nm to 6.072 nm.
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Chen, Yu-min, and 陳育民. "The effect of pre-immersing after electropolishing on the anodic film properties and electrolytic coloring ofaluminum." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/21925208113266747847.
Full textAbstract:
碩士大同大學
化學工程學系(所)
98
Aluminum due to high activity and light weight, good gloss, high electrical conductivity and thermal conductivity, it is widely applied in industry and our life. At present, many studies are looking a process to form a dense film on aluminum. This study adopts three different process before the anodizing treatment, one is the convrtional pretreatment,another is the polished treatment before anodization,the other is preimmersing in the ammonium molybdate before anodization.The polishing method has the advantage of reaching the surface leveling, gloss and smoothing to form the anodic film. Using the surface modifier of ammonium molybdate, a molybdenum oxide film would cover the aluminum surface, it can make the anodic process slowly and steadily to build a more dense film more hard oxide film. It was found that the use of polished anodized aluminum can make more holes and a larger aperture, but the structure is loose, the use of pre-immersing step to improve the corrosion resistance and hardness that decreased by the polished process. Though the immersing after polishing process can obtain a anodic film with better durability, but the Cu-coloring is with difficuty, the drawback can be overcomed by using AgNO3 for coloring, it can obtain the darker black film with hardness of 419.9Hv and ΔE* of 9.8 at 3A/dm2. While the single polishing process can obtain the blackest film with ΔE* of 6.53 at 2A/dm2 but it’s hardness drops to 312.3Hv.
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Liu, Hsin Hung, and 劉信宏. "The Electropolishing Behavior of Engineering Ti Alloy ( Ti-6Al-4V ) in A Sulfuric Acid – Ethanol Solution." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/45383186971554871827.
Full textAbstract:
碩士長庚大學
機械工程研究所
98
This study focused on the Ti-6Al-4V electropolishing of conduct, Titanium in the electrolytic paper slurry composition as a reference and try for the Ti-6Al-4V electropolishing, In comparing the various systems, collated and analyzed, Decided to use sulfuric acid - ethanol solution of the system Ti-6Al-4V electropolishing, temperature used at room temperature (25 ℃), Change its concentration and speed so that try to achieve whole-chip level and the effect of lighting, And for the electropolishing process to be discussed phenomenon. Experiment results show, Ti-6Al-4V in 2 M sulfuric acid - ethanol solution, the electropolishing surface after leveling get better results with the lighting, By AFM measurements of Ra value of about 2.34 nm, In 3 M sulfuric acid - ethanol solution, although the limits of current district wide, but low current density and big ups and downs, After electropolishing the surface formation, is not suitable to carry out acts of electropolishing. In 1 M sulfuric acid - ethanol solution, the limiting current zone and 2 M and 3 M compared to a very narrow, After electropolishing the surface of the ups and downs, and the shortcomings of a few more, were not suitable to carry out acts of Electropolishing. From the experiment into a Ti-6Al-4V in 2 M sulfuric acid - ethanol solution, temperature 25 ℃, set potential 9 V, fixed power of 150 Coulomb, 100 to 300 rpm speed parameter can be a very good surface shape. Electropolishing process, when the current density spiking upward, you will find that absorption in the Ti-6Al-4V samples off the surface of the translucent film, This film observed using SEM and TEM analysis, we found that this seems Amorphous organizations, However, a white film on the object seems Crystalline organizations, This inference may be a white object Ti-6Al-4V precipitates in determining the course of potential electropolishing off attached to film.
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Liao, Wei-You, and 廖偉佑. "A study of electropolishing and electrochemical behaviors of die-cast (AZ91D) and as-rolled magnesium alloys (AZ61E)." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/48346018042357560705.
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碩士長庚大學
機械工程研究所
93
Abstract The aim of this study was to investigate the electrochemical polishing behavior of the die-cast and as-rolled magnesium alloys (AZ91D) at 50, 60 and 70℃ in the phosphoric acid-ethanol mixed with 3:5, 1:1 and 5:3 volume-ratios respectively. To study the electrochemical behavior of the magnesium, a rotating disc electrode (RDE) was used. Before electrochemical polishing, anodic polarization curves of the RDE was carried out in the mixed liquids. Then potentiostatic polishing was conducted in the potential corresponding to limiting-current plateau. The polished surface was examined with OM, SEM and surface-roughness profiler. The results show that pleasingly leveling and brightening surface can be achieved, when polishing in higher phosphoric acid content (50～62.5Vol%) of the mixed liquid and under higher temperature (>50℃). The results of the electrochemical polishing surface can attain the Ra=0.09μm.
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Hu, Yao-Hsiang, and 胡曜翔. "THE EFFECT OF ELECTROPOLISHING ON THE ANODIC FILM AND ITS ELECTROLYTIC COLORING FROM A SECONDARY ANODIC PROCESS." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/mx7esy.
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碩士大同大學
化學工程學系(所)
102
The study was carried out by means of the method of electropolishing on the anodic films before secondary anodic treatment and then electrolytic coloring in cupric sulfate solution. It is expected that by this method a dense and regular oxidizing film on aluminum can be obtained and that the optimum operating conditions for obtaining a blackest film are found out. The experimental results show that electropolishing on the anodic films increase the size of pores and more regular, the secondary anodic treatment can also increase the size and the number of pores, after electropolishing and secondary anodic treatment on aluminum sheets make the thickness of the anodic colored film become thicker. From SEM and AFM we found the pores are larger and more than anodic treatment, secondary anodic treatment, and anodic treatment after electropolishing, also has a good effect for electrolytic coloring. We get the lowest ΔΕ*and reflectivity after coloring, but the hardness of the anodic colored film become lower. The optimal operating conditions for obtaining the blackest colored film are: electropolishing voltage 10Vdc, electropolishing time 30 min in phosphoric acid and ethanol, secondary anodic treatment current 2A/dm2, secondary anodic treatment time 30 min, electrolytic coloring voltage 20 Vac and electrolytic coloring time 120 minutes, the lower △E value, and reflectivity would be obtained. Those values are respectively 9.96 and 5.4%.
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Chen, Sin-Bang, and 陳心榜. "The influence of electropolishing,the change of sulfuric acid''s flow rate and sealing treatmeat on anodizing treatment." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/26657628478141447357.
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碩士國立中央大學
機械工程研究所
91
The aim of present study was to investigate the effects of three different process’s change on the aberration、burnish and transparency of anodizing layer. The material in this experiment was business 5052 H32 aluminum alloy. （1）Add electro-polishing treatment before anodizing treatment，and investigate the change of the aberration、burnish and transparency. The electrolyte using in electro-polishing treatment is the mixing bath with HClO4 and ethanol. By changing the voltage，electrolyting time and the sample’s roughness that was as receive, investigates the influence of electropolishing on the surface quality of samples. （2）Changed the electrolyte’s flow rate in the tank. It was using the sulfate acid process. All experiment conducted by using constant current-density. By changing the sulfate acid’s flow rate，investigated the influence of anodizing layer. （3）Changed the way of sealing .It used four ways to seal the anodizing layer after anodizing treatment, and compare with non- sealing sample. The measure tool are the coating thickness tester，spectrophotometer，SEM and glossmeter. The result is lElectropolishing is powerful to polish the 5052 sample，and can make the sample surface look mirrorlike. Electropolishing also can clean the surface and remove the grease ，oxide and inclusion，and affect the surface of anodizing flim. lIf the flow rate of sulfate acid in anodizing tank is more fast, the surface of anodizing film will be more even, and the L，a，b，gloss value will be equable. At the same time higher flow rate also will make the L value lower， the a value more greener，the b value more yellower. lAcceptive sealing way can improve the surface quality of anodizing film The anodizing film use steam sealing process is most diaphanous in the experiment. The anodizing film use nickl-acetate sealing process is easy to make a value more greener, b value more yellower, L value lower. So use nickl acetate sealing process would get more yellower and darker anodizing film.
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Chung, Yueh-Chun, and 鍾岳峻. "Effects of electropolishing treatment on surface roughness and mechanical properties of titanium-based materials fabricated by additive manufacturing." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/ez3cyx.
Full textAbstract:
碩士國立中山大學
材料與光電科學學系研究所
106
During the past years, the use of additive manufacturing (AM) technologies in a variety of fields has increased substantially. Because of the one-step manufacture and customization of designs, AM technologies have been more and more widely used in the application of the medical implants and aerospace components. Electron beam melting (EBM), which involves the layer-by-layer electron beam melting of powders, is one of the most promising AM technologies. However, the procedure of EBM process will make products get rougher surface due to melting pool which causes adjacent powder particles to be sintered to the surface without being melted. Under dynamic stress, notches caused by these bounded powders may cause stress concentration and may induce products fatigue. Hence, it is necessary to improve the surface quality by various post processes. On the other hand, internal or complicate structures are impossible to finish by conventional mechanical polishing methods. Therefore, electropolishing is a feasible method to improve the surface quality of Ti6Al4V EBM samples. This study is devoted to evaluating whether the electropolishing method would be the effective method or not. Firstly, the best electrolyte and parameters for Ti6Al4V EBM samples are searched out by different experimental condition designs. Secondly, surface quality, such as surface morphology and notches on the surface, are observed with a view to discussing the influence of stress concentration. Thirdly, mechanical properties, such as Young’s modulus, elongation, and yield stress, are measured to discuss the influence of different degrees of roughness on the surface. Lastly not the least, the electropolished-porous samples are analyzed by micro-CT. Experiment results show that the surface roughness of Ti6Al4V EBM solid samples can be improved from 23.4 μm to 5.3 μm by electropolishing with the electrolyte of perchloric acid, glacial acetic acid, and ethanol. For the Ti6Al4V EBM solid tensile specimens after optimum electropolishing, the tensile elongation can increase from 7.6% to 11.6%, with the surface roughness of the side surface of tensile specimen decreasing from 24.1 μm to 4.1 μm. However, for the porous Ti6Al4V EBM compression specimens, the results show that the polished porous specimens would result in worse mechanical property than the unpolished porous specimen, as a result of the over corrosion of external ligaments.
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Chao, Wei Chieh, and 趙偉捷. "A study of the electropolishing behavior of brass in aqueous phosphoric acid solutions by means of rotating cylinder electrode." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/17880918438929826434.
Full textAbstract:
碩士長庚大學
機械工程學系
100
The electropolishing behavior of 73-brass in phosphoric acid aqueous solutions was discussed in this study. The results showed that the anodic polarization curves of the 73-brass in phosphoric acid could be divided into active, limiting current and oxygen evolution region, and an obvious peak could be found between active and limiting current region. In order to explore the anodic dissociation behavior of 73-brass which was electropolished in different potential regions and find the best electropolishing parameters. In this experiment, 73-brass was electropolished in the peak, front-end, middle and rear of the limiting current region respectively by means of rotating cylinder electrode and rotating disk electrode. The surface morphology electropolished in middle of limiting current region could be found excellent effect by means of optical microscopy and scanning electron microscopy. Moreover, atomic force microscopy analysis showed that the minimum surface roughness value of 0.45 nm (Ra) could be obtained when electropolishing in 70 vol.% phosphoric acid with rotation speed of 500 rpm in middle of the limiting current region.
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Chen, Y. C., and 陳宥辰. "The electropolishing behavior of the Inconel 718 alloy in the perchloric and acetic mixed acids with different concentrations of perchloric acid." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/88766068604820247250.
Full textAbstract:
碩士長庚大學
機械工程研究所
95
The electropolishing behavior of the Inconel 718 alloy was studied by using rotating disc electrode (RDE) in the HClO4-CH3COOH mixed acids with different HClO4-concentrations. After electropolishing, surface morphologies of RDE specimens were examined with surface profiler, atomic force microscope and scanning electron microscope. According to the polished surfaces, three types of anodic dissolution behavior can be characterized in relation to the HClO4-content in mixed acids; namely, a leveling without brightening of the surface in 10 and 20 vol% HClO4, a leveling and brighten of the surface in 30 and 40 vol% HClO4, and a matt and gray surface in the mixed acids with 50 vol% or more HClO4. Anodic dissolution in the first and second dissolution types follows a mass-transfer controlled mechanism, in which a linear relationship between the reciprocal of limiting-current density and the reciprocal of square root rotation speed of RDE specimen can be detected. Owing to precipitation of a salt film on the polished surface of the Inconel 718 alloy, saturated dissolved metallic ions could be the chemical species for the mass-transfer controlled mechanism. The salt film, in addition, also enhances the corrosion resistance of the Inconel 718 alloy. This can be realized with the results of anodic potentiodynamic test in 1 M H2SO4. The electropolishing behavior of Inconel 718 alloy was studied by means of alternative current (AC) impedance test in the perchloric-acetic mixed acids at 25oC. The AC impedance test was conducted at the potential located in the limiting current plateau region with different potential amplitudes of 20, 200, 500 and 1000 mV, respectively. The results of AC impedance test show that large potential amplitudes will be recommended to obtain stable AC impedance spectra in the anodic dissolution under mass-transfer controlled mechanism. It can be recognized with the results of AC impedance test that precipitation of a salt film on the surface of Inconel 718 alloy was the main reason for mass-transfer controlled mechanism. That is, small semi-circles can be found with the Inconel 718 RDE specimens in the Nyquist diagrams in the high frequency domain when polishing at the potential located in the limiting-current plateaus.
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Pendyala, Prashant. "Generation, Characterization and Control of Nanoscale Surface Roughness." Thesis, 2014. http://etd.iisc.ac.in/handle/2005/3011.
Full textAbstract:
Surface roughness exists at many length scales-from atomic dimensions to meters. At sub-micron scale, the distribution of roughness is largely dependent on the process that generates the surface through the mechanisms of material removal/addition involved and the process parameters. The focus of the research is to quantitatively characterize the evolution of sub-micron scale surface roughness in the mechanical, chemical and electrochemical material removal techniques and study the influence of roughness on the mechanical behavior of surfaces.
High purity aluminum surfaces are subjected to surface dissolution techniques such as electropolishing, chemical etching and anodization. Owing to the lack of sufficient lateral resolution in conventional roughness measurement techniques and appropriate scale independent roughness characterization techniques, the effect sub-micron scale electrochemical inhomogeneities present on the surfaces have on the roughness evolution at various length scales has not been understood. In this work, the power spectral density method of roughness characterization is used to quantitatively evaluate the roughness length scales affected in the surface generation processes as a function of time. Results indicate that in the case of electropolishing, roughness is not uniformly reduced at all length scales. Further, cut-off frequencies are suggested to optimize the electropolishing process. In chemical etching, the nature of roughness produced is found to be dependent on the nature of the starting surface. The nature of surface and sub-surface structures produced in the initial stage of the anodization process, and the transition from a disordered to an ordered structure are studied.
In order to study the mechanical behavior of surfaces as a function of surface roughness, a single asperity indentation is modeled using nanoindentation of micropillar produced by focused ion beam machining of aluminum surfaces. Load-displacement curves are constructed to show the transition from a single asperity deformation to bulk deformation as function of indentation depth. Additionally, indentation responses of polymer coated surfaces with varying degree of roughness that were produced by the aforementioned surface generation processes are studied. it is shown how high interface roughness gives rise to high scatter both in loading and unloading portions of the load-displacement curves. Finally, porous alumina surface generated by the anodization process discussed above is indented to simulate a multi-asperity interaction.
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Pendyala, Prashant. "Generation, Characterization and Control of Nanoscale Surface Roughness." Thesis, 2014. http://hdl.handle.net/2005/3011.
Full textAbstract:
Surface roughness exists at many length scales-from atomic dimensions to meters. At sub-micron scale, the distribution of roughness is largely dependent on the process that generates the surface through the mechanisms of material removal/addition involved and the process parameters. The focus of the research is to quantitatively characterize the evolution of sub-micron scale surface roughness in the mechanical, chemical and electrochemical material removal techniques and study the influence of roughness on the mechanical behavior of surfaces.
High purity aluminum surfaces are subjected to surface dissolution techniques such as electropolishing, chemical etching and anodization. Owing to the lack of sufficient lateral resolution in conventional roughness measurement techniques and appropriate scale independent roughness characterization techniques, the effect sub-micron scale electrochemical inhomogeneities present on the surfaces have on the roughness evolution at various length scales has not been understood. In this work, the power spectral density method of roughness characterization is used to quantitatively evaluate the roughness length scales affected in the surface generation processes as a function of time. Results indicate that in the case of electropolishing, roughness is not uniformly reduced at all length scales. Further, cut-off frequencies are suggested to optimize the electropolishing process. In chemical etching, the nature of roughness produced is found to be dependent on the nature of the starting surface. The nature of surface and sub-surface structures produced in the initial stage of the anodization process, and the transition from a disordered to an ordered structure are studied.
In order to study the mechanical behavior of surfaces as a function of surface roughness, a single asperity indentation is modeled using nanoindentation of micropillar produced by focused ion beam machining of aluminum surfaces. Load-displacement curves are constructed to show the transition from a single asperity deformation to bulk deformation as function of indentation depth. Additionally, indentation responses of polymer coated surfaces with varying degree of roughness that were produced by the aforementioned surface generation processes are studied. it is shown how high interface roughness gives rise to high scatter both in loading and unloading portions of the load-displacement curves. Finally, porous alumina surface generated by the anodization process discussed above is indented to simulate a multi-asperity interaction.
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Nardo, Leonardo De. "Instrumentos endodônticos de eletroerosão." Master's thesis, 2019. http://hdl.handle.net/10284/8511.
Full textAbstract:
Introdução: A instrumentação Endodôntica tem desenvolvido muitos inovadores
instrumentos que proporcionam uma instrumentação mais segura, simples e eficaz. O desafio
dessas limas é de simplificar o número de passos clínicos, sem deixarem de ser capazes de ser
utilizadas várias vezes mantendo um nível de resistência sempre elevado.
Objectivos e metodologia: realizar uma revisão bibliográfica narrativa das gerações do
sistema de instrumentação Hyflex, CM e EDM, analisando as diferenças entre os
instrumentos e avaliando com maior atenção a estrutura das limas EDM fabricadas por um
processo inovador chamado eletroerosão (eletropolishing) que lhes confere, maior resistência
à fratura, com a capacidade de voltarem à forma original após o processo de esterilização.
Conclusões: as limas Hyflex tem características distintas e apresentam várias vantagens em
comparação com outros instrumentos existentes no mercado. A grande eficiência das Hyflex
EDM torna-as numa boa opção para a instrumentação de canais radiculares com grau de
complexo elevado.Introduction: Endodontic instrumentation has developed many innovative instruments that provide safer, simpler and more effective instrumentation. The challenge of these files is to simplify the number of clinical steps, without ceasing to be able to be used several times maintaining a level of resistance always high. Objectives and methodology: to carry out a narrative bibliographic revision of the generations of the Hyflex, CM and EDM instrumentation system, analyzing the differences between the instruments and evaluating with greater attention the structure of the EDM files manufactured by an innovative process called electroerosion (electropolishing) , greater resistance to fracture, with the capacity to return to the original shape after the sterilization process. Conclusions: Hyflex files have different characteristics and have several advantages compared to other instruments on the market. The high efficiency of the Hyflex EDM makes them a good choice for instrumentation of root canals with high complex degree.