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Dissertations / Theses on the topic 'Chromium Oxidation'

Author: Grafiati

Published: 4 June 2021

Last updated: 31 January 2023

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1

Gould, Peter John. "The high temperature oxidation of chromium and chromium implanted with cerium." Thesis, Imperial College London, 1991. http://hdl.handle.net/10044/1/46790.

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2

Villalobos, Aragon Alejandro. "Using chromium stable isotopes to monitor chromium reactive transport oxidation experiments and field studies /." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2009. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.

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3

Sole, Kathryn Clare. "The kinetics and mechanism of the oxidation of chromium (III) chloride." Thesis, Rhodes University, 1989. http://hdl.handle.net/10962/d1004921.

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The kinetic behaviour of anhydrous CrCl₃ in gaseous oxidising atmospheres has been examined in the temperature range 350 to 630°C in order to identify optimum reaction conditions and to establish the mechanism by which the reaction is controlled. The reaction under consideration is CrCl₃ (s) + ¾ O₂ (g) → ½ Cr₂O₃ (s) + ³/₂ Cl₂ (g). The main experimental techniques used were isothermal and programmed-temperature thermogravimetry, supplemented by scanning electron-microscopy, surface-area determinations and porosity measurements. The effects of sample pelletisation, gas flowrate, temperature, oxy

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4

Susanto, Benny Laurensius Materials Science &amp Engineering Faculty of Science UNSW. "Kinetics of carbide dissolution in chromium + molybdenum steels during oxidation." Awarded by:University of New South Wales. Materials Science and Engineering, 2004. http://handle.unsw.edu.au/1959.4/19385.

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Iron-based alloys containing 15% chromium, 2-3% molybdenum and 0.02-1.7% carbon, consisting of M23C6 and M6C carbides in an austenitic matrix were oxidised at 8500C to study their oxidation resistance and a precipitate-free zone formation. Alloy design was carried out using a thermodynamic software Thermo-Calc. Carbides in these alloys were expected to dissolve during oxidation, releasing chromium required for the protective oxide formation. Decarburisation of the matrix was expected to trigger the carbide dissolution, and form a precipitate-free zone. Transformation of the austenitic into fer

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5

JACOB, YVAN PIERRE. "A pre-normative research on the isothermal and cyclic oxidation high temperature oxidation behaviour of chromium." Clermont-Ferrand 2, 2001. http://www.theses.fr/2001CLF22279.

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De nombreux parametres experimentaux intervenant lors de l'oxydation du chrome a haute temperature ont ete etudies afin de comprendre leurs effets sur la croissance et l'integrite de la couche de chromine qui se forme lors de cette oxydation. Hormis les techniques classiques utilisees pour l'etude de l'oxydation a haute temperature, nous nous sommes servis de la methode d'activation nucleaires des couches minces (tla) permettant de quantifier les pertes eventuelles d'oxyde par ecaillage lors d'oxydations isothermes ou cycliques. Le but de ce travail, par l'etude systematique de differents para

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6

Van, der Merwe Werner. "Ozone treatment of chromium waste materials / Werner van der Merwe." Thesis, North-West University, 2011. http://hdl.handle.net/10394/9392.

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Ozonation, or advanced oxidation processes (utilising ozone decomposition products as oxidants) are widely used in industrial waste water and drinking water treatment plants. In these applications the use of ozone is based on ozone and its decomposition by-products being strong oxidants. A case study revealed that several waterworks in South Africa successfully utilise ozone as a pre-oxidant for the treatment of raw waters. South Africa holds more than three quarters of the world’s viable chromium ore (chromite) reserves. Subsequently the Cr-related industry-within is considerable in size and

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7

Rogers, Nathan D. "Chromium Oxidation by Disinfectants and Oxidants Used in Drinking Water Treatment." DigitalCommons@USU, 2016. https://digitalcommons.usu.edu/etd/5028.

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The USEPA Maximum Contaminant Level (MCL) for Total Chromium in drinking water is 100 μg/L. Total chromium includes both trivalent chromium (Cr(III), a trace nutrient) and hexavalent chromium (Cr(VI), a probable human carcinogen). The State of California set a Cr(VI)-specific MCL of 10 μg/L in 2014, and USEPA is considering a new federal MCL for Cr(VI). This would have a significant impact on drinking water systems across the US, with estimated annual cost of compliance between $0.6 to 5.1 billion per year. While Cr(VI) is the species of concern for health effects, water utilities must also co

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8

Wang, Haijuan. "Investigations on the Oxidation of Iron-chromium and Iron-vanadium Molten Alloys." Doctoral thesis, KTH, Materialens processvetenskap, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-12955.

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With the progress of high alloy steelmaking processes, it is essential to minimize the loss of valuable metals, like chromium and vanadium during the decarburization process, from both economic as well as environmental view points. One unique technique to realize this aim, used in the present work, is the decarburization of high alloy steel grades using oxygen with CO2 in order to reduce the partial pressure of oxygen. In the present work, the investigation on the oxidation of iron-chromium and iron-vanadium molten alloys under CO2-O2 mixtures was carried out and presented in this dissertation

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9

Soleimani-Dorcheh, Ali [Verfasser]. "Oxidation-Nitridation of Chromium at High Temperatures and its Mitigation by Alloying / Ali Soleimani-Dorcheh." Aachen : Shaker, 2017. http://d-nb.info/1138178543/34.

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10

Zimmermann, Janina [Verfasser]. "Atomistic modeling of the oxidation of titanium nitride and cobalt-chromium alloy surfaces / Janina Zimmermann." Aachen : Shaker, 2010. http://d-nb.info/1122546599/34.

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11

李偉安 and Wai-on Lee. "Oxidation chemistry and electrochemistry of ruthenium and chromium complexes of macrocyclic tertiary amines and aromatic diimines." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1989. http://hub.hku.hk/bib/B31231846.

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12

Lee, Wai-on. "Oxidation chemistry and electrochemistry of ruthenium and chromium complexes of macrocyclic tertiary amines and aromatic diimines /." [Hong Kong : University of Hong Kong], 1989. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12505286.

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13

Ventura, Julieta Angelica. "High temperature oxidation behavior of Nb-20Mo-15Si-5B-20Cr alloy." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2009. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.

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14

Hamdani, Fethi. "Improvement of the corrosion and oxidation resistance of Ni-based alloys by optimizing the chromium content." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0012/document.

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Cette étude fondamentale est dédiée à la compréhension de l’influence de la composition chimique, notamment la teneur en chrome, des alliages base de nickel sur leur mécanismes de corrosion et d’oxydation. La corrosion sous contrainte intergranular (CSCIG) est un mode de dégradation qui affecte de nombreux alliages au sein des réacteurs à eau pressurisé. En particulier, les alliages base nickel tubes des générateur de vapeur (GV). La sensibilité à la CSC est désormais dépend de la teneur en chrome, ce qui a conduit au remplacement de l’alliage 600 (Ni-16Cr-9Fe) par l’alliage 690 (Ni-30Cr-9Fe).

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15

Marin, Cordoba Roberto. "Chromium Carcinogenesis: Characterization of DNA damaging Intermediates by EPR ³¹P NMR, HPLC, ESI-MS and Magnetic Susceptibility." Ohio University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1261417590.

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16

Portillo, Benedict I. "High temperature oxidation behavior of the Nb-W-Cr system and response of boron additions." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2008. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.

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17

Pillay, Kriveshini. "A kinetic and mechanistic study on the oxidation of chromium oxide in pure chemicals and in ferrometallurgical slags." Master's thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/5415.

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Bibliography: leaves 103-108.<br>Chromium can exist in a number of oxidation states but the environmentally stable forms are trivalent (Cr(III)) and hexavalent (Cr(VI)) chromium. These two forms are noted for their different degrees of toxicity and mobility. Hexavalent chromium is more toxic and mobile and has been responsible for a number of illnesses in humans (Sheehan et. al., 1991). Elemental chromium and its compounds have a variety of uses in the industrial sector. The ferrometallurgical industry in particular makes use of chromium since this element imparts properties such as hardness a

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18

Acerson, Mark Jeffrey. "Synthesis of 4'-Ester Resveratrol Analogues, Chromium Trioxide Oxidation of Terpenes, and Synthesis of Mimics of (-)-Englerin A." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/5458.

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4’ -ester analogues of resveratrol were synthesized using reaction conditions developed to produce mono-ester products in the presence of two other unprotected phenols. Basic conditions were employed to deprotonate the most acidic 4’ phenol followed by addition of anhydrides or acid chlorides to give the ester product. The reaction favored 4’-ester formation in polar aprotic solvents with DMSO being the optimal solvent. (—)-Englerin A is a guaiane-type sesquiterpene containing two ester side chains. Mimics of (—)-englerin A were proposed that retained the ester side chains while replacing t

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19

Högström, Jonas. "Corrosion and Surface Studies of Stainless Steel and Chromium Carbide Thin-Films." Doctoral thesis, Uppsala universitet, Institutionen för kemi - Ångström, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-208410.

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Although the passive films that form on stainless steels have been extensively studied, the concentration depth profiles are not fully understood. Their thinness makes passive films hard to study, but angle-resolved X-ray photoelectron spectroscopy (ARXPS) is a non-destructive technique that can be used to obtain depth information. An iterative approach to deconvolute ARXPS measurements into depth profiles is discussed, and the chemistry of passive films on a molybdenum-containing 316L stainless steel is investigated. Bipolar electrochemistry, in which the sample is placed along an electric fi

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20

Paulo, Glauco Dias. "Estudo da influência do teor de cromo na microestrutura, dureza e oxidação de um ferro fundido branco multicomponente (FFBM)." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/97/97134/tde-06022017-104006/.

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Foi estudado o efeito da variação do teor de cromo, em 3%, 6% e 9% em massa, na microestrutura, dureza e oxidação de um ferro fundido branco multicomponente. O Thermo-Calc versão 5 foi a ferramenta utilizada para cálculos termodinâmicos que resultaram na previsão das fases formadas para cada liga. Experimentalmente, foram realizados os seguintes estudos: i) caracterização microestrutural das ligas fundidas com os diferentes teores de cromo na condição bruta de fundição; ii) ensaio de dureza na matriz duplamente revenida em cinco diferentes temperaturas entre 400 °C e 600 °C; e iii) ensaio de t

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21

Weaver, Robert M. "Comparison of the Reactivity of Various Mn-Oxides With CrIIIaq: Microscopic and Spectroscopic Observations of Dissolution, Cr-sorption and Cr and Mn Redox Interactions." Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/29365.

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The interaction between CrIIIaq and seven different Mn-oxides (6 monomineralic, 1 synthetic) have been observed in pH ~4.4 HNO3 and pH ~4.4 ~10-4M CrIIIaq solutions. For each mineral-solution interaction, the aqueous chemical concentrations (e.g. [Mn]aq, [Cr]aq, [CrVIaq]) were measured with time. Reacted samples were examined by XPS to determine if, and to what extent, the surface chemical states of Cr, Mn and O had changed. Microscopic observations of the reacted surfaces were obtained using AFM and high-resolution, low-voltage FESEM. The solubility of the Mn-oxides in the acidic, non-Cr b

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22

O'Neal, Stephen Vernon. "A kinetic study of the chromium (VI) - arsenic (III) reaction in pyridine-pyridinium buffer solutions containing oxalate." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/104524.

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23

Kamaludeen, Sara Parwin Banu. "Biotic-abiotic transformations of chromium in long-term tannery waste contaminated soils : implications to remediation." Title page, table of contents and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09PH/09phk15.pdf.

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Bibliography: leaves 166-180. Determines the effect of chromium on the soil microbial community and its activity, the biotic-abiotic mechanisms involved in chromium oxidation, and phytostabilization of chromium using plants and organic amendment in tannery-waste contaminated soil.

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24

Soleimani-Dorcheh, Ali Verfasser], Michael [Akademischer Betreuer] Schütze, and Wolfgang [Akademischer Betreuer] [Bleck. "Oxidation-nitridation of chromium at high temperatures and its mitigation by alloying / Ali Soleimani-Dorcheh ; Michael Schütze, Wolfgang Bleck." Aachen : Universitätsbibliothek der RWTH Aachen, 2017. http://d-nb.info/1156923468/34.

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25

Soleimani-Dorcheh, Ali [Verfasser], Michael Akademischer Betreuer] Schütze, and Wolfgang [Akademischer Betreuer] [Bleck. "Oxidation-nitridation of chromium at high temperatures and its mitigation by alloying / Ali Soleimani-Dorcheh ; Michael Schütze, Wolfgang Bleck." Aachen : Universitätsbibliothek der RWTH Aachen, 2017. http://d-nb.info/1156923468/34.

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26

Jiang, Wenjun. "The Investigation of Photocatalysts and Iron Based Materials in the Oxidation and the Adsorption of Toxic Organic and Chromium Materials." FIU Digital Commons, 2013. http://digitalcommons.fiu.edu/etd/1023.

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The presences of heavy metals, organic contaminants and natural toxins in natural water bodies pose a serious threat to the environment and the health of living organisms. Therefore, there is a critical need to identify sustainable and environmentally friendly water treatment processes. In this dissertation, I focus on the fundamental studies of advanced oxidation processes and magnetic nano-materials as promising new technologies for water treatments. Advanced oxidation processes employ reactive oxygen species (ROS) which can lead to the mineralization of a number of pollutants and toxins. Th

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27

Brose, Dominic A. "Oxidation-reduction transformations of chromium in aerobic soils and the role of electron-shuttling quinones in chemical and microbiological pathways." College Park, Md.: University of Maryland, 2008. http://hdl.handle.net/1903/8316.

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Thesis (M.S.) -- University of Maryland, College Park, 2008.<br>Thesis research directed by: Dept. of Natural Resource Sciences and Landscape Architecture. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

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28

Bishop, Michael Edward. "Fe(III) reduction in Hanford sediments and its application to chromium immobilization." Miami University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=miami1438442637.

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29

Marin, Córdoba Roberto. "Chromium carcinogenesis characterization of DNA damaging intermediates by EPR ³¹P NMR, HPLC, ESI-MS and magnetic susceptibility /." Ohio : Ohio University, 2010. http://www.ohiolink.edu/etd/view.cgi?ohiou1261417590.

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30

Lindsay, John Christopher. "Stress corrosion cracking and internal oxidation of alloy 600 in high temperature hydrogenated steam and water." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/stress-corrosion-cracking-and-internal-oxidation-of-alloy-600-in-high-temperature-hydrogenated-steam-and-water(1d6b037c-baf1-4397-a6c9-43835e7bb39a).html.

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In this study, the possibility of using low pressure hydrogenated steam to simulate primary water reactor conditions is examined. The oxides formed on Alloy 600 (WF675) between 350 Celsius and 500 Celsius in low pressure hydrogenated steam (with a ratio of oxygen at the Ni/NiO to oxygen in the system of 20) have been characterised using analytical electron microscopy (AEM) and compared to oxide that formed in a high pressure water in a autoclave at 350 Celsius with 30 cc/kg of hydrogen. Preferential oxidation of grain boundaries and bulk internal oxidation were observed on samples prepared by

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31

PILLIS, MARINA F. "Estudo do comportamento de sulfetacao de ligas Fe20Cr." reponame:Repositório Institucional do IPEN, 2001. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10925.

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32

Nicolas, André. "Etude de l'Evolution Physico-Chimique du Substrat lors de l'Oxydation à Haute Température des Alliages Modèle Ni-Cr à Faible Teneur en Chrome et de l'Alliage Modèle Ni-16Cr-9Fe." Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 2012. http://tel.archives-ouvertes.fr/tel-00848591.

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Le travail réalisé au cours de cette thèse concerne l'analyse des conséquences de l'oxydation à 950°C des alliages base Ni sur la composition de l'alliage à proximité de l'interface alliage/oxyde. Deux catégories d'alliages ont été analysées : alliages à faible teneur en chrome conduisant à l'oxydation interne et l'alliage chromino-formeur Ni-16Cr-9Fe.Une description complète des mécanismes de l'oxydation interne du chrome est obtenue à partir du développement du modèle analytique de Wagner d'oxydation interne et du développement du modèle numérique de Feulvarch. Ces modèles décrivent l'évolut

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33

Evin, Harold. "Low Cr alloys with an improved high temperature corrosion resistance." Thesis, Dijon, 2010. http://www.theses.fr/2010DIJOS082/document.

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Les aciers ferritiques à faible teneur en chrome tel que le T/P91 sont largement utilisés dans les centrales de productions d’électricité pour leurs bonnes propriétés mécaniques et leur faible coefficient d’expansion thermique. Cependant, la demande croissante en énergie alliée à la nécessité de réduire les émissions de gaz à effet de serre, conduisent à envisager l’augmentation des conditions d’utilisation (température et pression) de ces matériaux. Des études ont montré qu’en modifiant la température de fonctionnement et la pression de vapeur d’eau de 538°C/18.5 MPa à 650°C/30 MPa, le rendem

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34

Alves, Lucas Campaner. "Caracterização do cromo presente no lodo de galvanoplastia: avaliação técnica e econômica de processos de remoção." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-29032016-084227/.

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O lodo gerado em processos de galvanoplastia é classificado pela ABNT NBR 10.004/04 como perigoso (classe I). Na literatura encontram-se poucos estudos referentes à recuperação do cromo presente no lodo gerado em sistemas de tratamento de efluentes de indústrias de galvanoplastia. Neste sentido, o presente estudo avaliou a remoção do cromo presente no lodo de galvanoplastia por meio de dois processos, visando avaliar à eficiência técnica e a viabilidade econômica de ambos. O Processo 1 consistiu na remoção do cálcio utilizando o ácido cítrico, seguida de lixiviação ácida. Na etapa de oxidação,

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35

Schmucker, Éric. "Compréhension et modélisation des mécanismes de corrosion des alliages chromino-formeurs dans les verres nucléaires." Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0166/document.

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La gestion des déchets radioactifs se fait par confinement des déchets radioactifs dans une matrice vitreuse. Il est réalisé par fusion inductive à 1150°C dans des pots constitués de superalliages riches en chrome. Ces pots sont soumis à une corrosion par le verre entrainant à terme leur remplacement. La protection contre la corrosion par le verre est assurée par l’établissement d’une couche d’oxyde protectrice Cr2O3 à la surface de l’alliage. Un alliage binaire chromino-formeur (Ni-30Cr) a été choisi comme alliage d’étude. Trois compositions de verre sodo- et borosilicatées sont choisies dans

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Harry, I. D. "Modification and characterisation of carbon fibre ion exchange media." Thesis, Loughborough University, 2008. https://dspace.lboro.ac.uk/2134/14123.

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This thesis examines the use of electrochemically treated viscose rayon based activated carbon cloth (ACC) for the removal of metal ions from aqueous effluent streams. Two types of treatment were performed: (i) electrochemical oxidation and (ii) electrochemical reduction to enhance cation and anion sorption capacities of the ACC, respectively. Electrochemical oxidation resulted in a loss of 61% BET surface area due to blockage of pores through formation of carboxylic acidic groups but its cation exchange capacity and oxygen content increased by 365% and 121%, respectively. The optimum constant

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37

Sakout, Mohammed. "Contribution de la spectrométrie X à l'étude des degrés d'oxydation du vanadium et du chrome dans les oxydes mixtes de structure spinelle." Rouen, 1989. http://www.theses.fr/1989ROUES002.

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Les déplacements chimiques expérimentaux observés à partir des spectres des oxydes simples et d'oxydes de Cr ou de V de structure spinelle à degré d'oxydation connu permettent d'établir une relation entre la valeur de ce déplacement chimique et le degré d'oxydation. Applications: 1) mise en évidence d'une très faible teneur en V (ii) dans les composés du système Fe(1+x)O(4) 2) dosage semiquantitatif du Cr (vi) dans les catalyseurs "chromite de cuivre"

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38

Varela, Júnior Jaldyr de Jesus Gomes. "DESEMPENHO DE ELETRODOS Pt/C, Pt3Cr/C E PtCr/C PARA APLICAÇÕES EM CÁTODOS DE CÉLULAS A COMBUSTÍVEL DE METANOL DIRETO." Universidade Federal do Maranhão, 2006. http://tedebc.ufma.br:8080/jspui/handle/tede/928.

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39

Michau, Alexandre. "Dépôts chimiques en phase vapeur de revêtements à base de chrome sur surfaces complexes pour environnements extrêmes : expérimental et simulation." Thesis, Toulouse, INPT, 2016. http://www.theses.fr/2016INPT0088/document.

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La protection des gaines de combustible de réacteur nucléaire contre l’oxydation à haute température en conditions accidentelles est essentielle pour garantir leur intégrité, c’est-à-dire celle de la première barrière de confinement. Celle-ci peut s’effectuer par le dépôt d’un revêtement sur leur paroi interne et ce sont les procédés CVD qui sont les plus à même de le faire. Il s’agit plus précisément du procédé DLI-MOCVD qui a été utilisé ici pour déposer des revêtements à base de chrome (chrome métallique Cr(S) cristallisé) et de carbures de chrome (carbures de chrome CrxCy amorphes non recy

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40

FERNANDES, STELA M. de C. "Influencia de terras-raras sobre a oxidacao de ligas formadoras de cromia." reponame:Repositório Institucional do IPEN, 1999. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10780.

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41

Wongpromrat, Wichitra. "Étude de la sublimation du chrome lors de l’oxydation haute température de l’alliage AISI 441 et recherche de solutions de protection." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAI070/document.

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Les aciers inoxydables ferritiques sont actuellement les meilleurs candidats pour répondre au cahier des charges des matériaux destinés aux interconnexions de piles à combustibles à oxyde solide (SOFC acronyme anglo-saxon pour Solid Oxide Fuel Cell). Cependant, du coté du compartiment cathodique de ces piles, le phénomène de sublimation du chrome à haute température conduit à des dégradations importantes, réduisant ainsi la durée de vie en service des SOFC. Les objectifs de ce travail de thèse sont (i) d'étudier le phénomène de sublimation du chrome sur l'acier inoxydable ferritique AISI 441 e

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Othman, Norinsan Kamil Materials Science &amp Engineering Faculty of Science UNSW. "Steam effects on cyclic oxidation of chromia forming alloys." Awarded by:University of New South Wales. Materials Science & Engineering, 2009. http://handle.unsw.edu.au/1959.4/44528.

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High temperature oxidation of Fe-Cr alloys with Cr levels of 9-30 wt% has been investigated by using isothermal and cyclic experiments at 600, 700 and 950??C. The mixed gases Ar-20%02, Ar-20%02H20, Ar-5%02-20%H20, Ar-10%H2-5%H20 and Ar-10% H2-20%H20 at total pressure of I atm were used. The effect of lanthanum alloying on Fe-Cr alloy oxidation was also studied. In general, increasing alloy chromium levels reduced the oxidation rate. In isothermal oxidation at 700??C, a protective chromia layer was formed in dry oxygen for Fe9Cr. Alloys with Cr???17% formed protective chromia layers in all gas

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Bataillou, Léa. "Modélisation de l'oxydation à haute température des alliages Ni-Cr." Thesis, Toulouse, INPT, 2019. http://www.theses.fr/2019INPT0104/document.

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Il est important pour l’industrie nucléaire de mener des études amont pour mieux appréhender les phénomènes en lien avec la corrosion des alliages chromino-formeurs. Cette étude a pour objectif de mieux comprendre les paramètres influant sur les mécanismes et la cinétique de croissance des couches de chromine formées par oxydation à haute température. Ce travail s’articule en deux parties complémentaires : une partie de modélisation qui est focalisée sur les aspects cinétiques, et une partie expérimentale axée sur la compréhension des mécanismes de croissance de la chromine. La partie modélisa

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Conrath, Élodie. "Élaboration et caractérisation de superalliages base chrome pour utilisation lors du fibrage centrifuge du verre à très haute température." Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0018.

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Le procédé industriel TEL permet de fabriquer de la laine de verre en fibrant du verre en fusion. La pièce principale de ce procédé est « l’assiette de fibrage », qui est soumise à de nombreuses contraintes en service (oxydation, corrosion, érosion et fluage). Elle est actuellement élaborée par fonderie et réalisée en superalliage base nickel ou base cobalt. Fibrer de nouveaux types de verre impliquant des températures de travail plus élevées nécessite un nouveau type de superalliage. Le chrome est un candidat idéal pour être l’élément principal d’une assiette de par sa haute température de fu

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Woodbridge, Nesta. "Mechanistic studies relevant to chromate toxicity." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267077.

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Pansani, Mariele Castilho. "Efeito da suplementação de cromo na resistência insulínica, na dislipidemia, na inflamação e no estresse oxidativo de pessoas HIV-positivo com lipodistrofia." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/17/17138/tde-24042018-174804/.

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Introdução: Os antirretrovirais (ARV) levam ao desenvolvimento de alterações metabólica, composta por dislipidemias, intolerância à glicose, resistência insulínica, hipertensão e lipodistrofia, associadas ao aumento do risco de doenças cardiovasculares. O cromo é um mineral essencial envolvido no metabolismo dos carboidratos e lipídeos. Ele está relacionado com a melhora da sensibilidade insulínica, das anormalidades metabólicas e da composição corporal. Objetivo: Avaliar o efeito da suplementação com cromo em pessoas HIV-positivo com lipodistrofia em TARV em marcadores do metabolismo da glico

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Delaunay, François. "Etude de l'influence des éléments mineurs d'addition sur l'oxydation à haute température d'alliages base nickel." Rouen, 1997. http://www.theses.fr/1997ROUES029.

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La compréhension des phénomènes d'oxydation à haute température des alliages base nickel revêt un intérêt particulier pour l'industrie nucléaire. Les performances de ces alliages, tout comme celles des aciers, sont fortement influencées par les différents éléments mineurs d'addition. Six alliages commerciaux ont été traités entre 800°C et 1000°C sous air et étudiés à l'aide des méthodes d'analyse complémentaires suivantes : spectroscopie de photoélectrons induits par un rayonnement X, spectroscopie infrarouge à transformée de Fourier, diffraction des rayons X et microscopie électronique à bala

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Alexiou, Amanda Elton. "The effects of chromia coatings on the oxidation characteristics on Ni and Ni-20Cr." Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/15046.

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Karamullaoglu, Gulsun. "Dynamic And Steady-state Analysis Of Oxidative Dehydrogenation Of Ethane." Phd thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606269/index.pdf.

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In this research, oxidative dehydrogenation of ethane to ethylene was studied over Cr-O and Cr-V-O mixed oxide catalysts through steady-state and dynamic experiments. The catalysts were prepared by the complexation method. By XRD, presence of Cr2O3 phase in Cr-O<br>and the small Cr2O3 and V2O4 phases of Cr-V-O were revealed. In H2-TPR, both catalysts showed reduction behaviour. From XPS the likely presence of Cr+6 on fresh Cr-O was found. On Cr-V-O, the possible reduction of V+5 and Cr+6 forms of the fresh sample to V+4, V+3 and Cr+3 states by TPR was discovered through XPS. With an O2/C2H6 fe

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Gheno, Thomas. "Oxydation et carburation d'alliages modèles chromino-formeurs dans le dioxyde de carbone." Thesis, Toulouse, INPT, 2012. http://www.theses.fr/2012INPT0060/document.

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La capture du carbone de combustion implique le transport de gaz riches en CO2 a haute temperature. Cette etude vise a preciser les facteurs controlant l'oxydation d'alliages chromino-formeurs dans ces environnements. Des alliages modeles Fe–Cr et Fe–Cr–Ni ont ainsi ete exposes a des melanges Ar–CO2–H2O a 650 et 800 °C, et les produits de reaction examines a l'aide de techniques de metallographie conventionnelles. La precipitation de carbures sous des couches d'oxyde indique une sursaturation en carbone a l'interface metal/oxyde, par rapport a l'atmosphere exterieure. Sur la base d'un modele d

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