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Journal articles on the topic 'Furnace brazing process'
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1
Bach, Friedrich Wilhelm, Kai Möhwald, and Ulrich Holländer. "Physico-Chemical Aspects of Surface Activation during Fluxless Brazing in Shielding-Gas Furnaces." Key Engineering Materials 438 (May 2010): 73–80. http://dx.doi.org/10.4028/www.scientific.net/kem.438.73.
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Continuous process brazing in shielding-gas furnaces is tailor-made for manufacturing mass production components by means of brazing technology. Which brazing tasks can actually be carried out by a shielding-gas furnace, depend on many ancillary conditions. In particular these are, besides the component size and joint geometry, the base materials and brazing filler metals as well as the material specific process parameters which are to be maintained in a continuous furnace in order that a process assured brazing can be guaranteed. In this context, the activation of the component's surfaces play a central role for wetting with the braze melt. Within the scope of this contribution, the variables and ancillary conditions concerning this matter are presented and discussed using the brazing process on stainless steels as an example.
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Xie, Xian, Gao Feng Quan, Xiue Gu, Xing Ming Liu, and Jia Le Sun. "A Study on Brazing Process and Mechanical Properties of AZ31 Magnesium Alloy." Advanced Materials Research 418-420 (December 2011): 792–95. http://dx.doi.org/10.4028/www.scientific.net/amr.418-420.792.
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The brazing process of magnesium alloy AZ31 was studied, and the mechanical properties of the weld were examined, and the main factors were analyzed through brazing furnace tests in this work. Only with the protection of self-made brazing flux, a lap joint with the average shear strength of 30MPa could be obtained in an ordinary resistance furnace without inert gas protection, which is much better than that without flux in which the shear strength is lower than 10MPa.
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Rogalski, Grzegorz, Michał Landowski, Aleksandra Świerczyńska, Jerzy Łabanowski, and Jacek Tomków. "Qualification of brazing procedure for furnace brazing of austenitic steel according to requirements of the ASME BPVC section IX." Welding Technology Review 91, no. 9 (2019): 13–24. http://dx.doi.org/10.26628/wtr.v91i9.1070.
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The article presents the procedure for qualifying brazing technology in a vacuum furnace on the example of stainless steel elements joined with copper filler material from the F-No group. 105, in accordance with the ASME Sec. IX, part QB (ASME Boiler and Pressure Vessel Code. Qualification Standard for Welding, Brazing and Fusing; Procedures; Welders; Brazers; and Welding, Brazing and Fusing Operators). The essential variables of the furnace brazing process are discussed in relation to the requirements of the protocol of qualified PQR (Procedure Qualification Record) and BPS (Brazing Procedure Specification) in accordance with the ASME Sec. IX. The requirements for joints by the calculation code ASME Sec. VIII div.1 (Rules of Construction of Pressure Vessels), related to the working temperature of the designed device have also been taken into account. The paper presents examples of brazed joints made and their properties (strength, fill level of the clearance) obtained on the basis of the carried out tests. Attention was paid to the technological aspects during the performance of brazed joints using vacuum furnaces.
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Kumar, Sandeep, Abhishek Upadhyay, Pal Dinesh Kumar, and Arun Agarwal. "Vacuum Brazing of Molybdenum – Kovar and Evaluation of its Joint Strength." Materials Science Forum 830-831 (September 2015): 282–85. http://dx.doi.org/10.4028/www.scientific.net/msf.830-831.282.
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This paper explains the technique of vacuum brazing for joining Molybdenum and Kovar. Joining of Molybdenum and Kovar is difficult because of difference in their mechanical properties and Melting Points. Kovar is an alloy of Fe, Ni , Co (composition : Ni 29% , Co 17% , rest Iron) . Molybdenum is a refractory material and its joint with Kovar is used for high temperature applications. Various parameters affecting the vacuum brazing process , vacuum furnace and factors affecting joint strength are discussed.Vacuum brazing of Molybdenum and Kovar samples was carried out inside vacuum brazing furnace using Copper a filler material. Vacuum level of furnace hot zone was maintained better than 10-6 mbar. The joint-strength was evaluated in Universal testing machine with the help of fixtures as per AWS C 3.2 Standard for testing strength of brazed joints. Ram tensile test was conducted. Factors affecting the joint strength of brazed joints like external compressive weight, diffusion of filler material into the parent materials, surface roughness of parent materials, surface flatness have been discussed. Joint strength of 75 MPa is obtained. Failure was found at the brazed joint interface.
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Wang, Xin Hong, Zeng Da Zou, Min Zhang, Si Li Song, and Shi Yao Qu. "Bonding Strength and Microstructure of Cermet/Cu-Based Alloy Composite Brazed Coatings." Key Engineering Materials 297-300 (November 2005): 154–59. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.154.
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WC-TiC-Co cermet and CuZnNi alloy composite coatings were produced on mild steel by a high temperature inside-furnace brazing technique. The microstructure, phase constituents and interfacial diffusion behavior of cermet and Cu-based alloy were investigated by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron probe microanalysis (EPMA) and X-ray diffraction. The tensile strength and wear property of composite coatings were also investigated. The results show that crème particles were not decomposed severely during the inside- furnace brazing process. The microstructure of the matrix is α and β phases. Diffusion occurred at the cermet/Cu-based alloy interface. The tensile strength of the composite coatings reached 240-300MPa, which depended on the brazing temperature and was far higher than that of the flame hardfacing layers. Cermet fracture was basically a brittle fracture in nature and matrix involves ductile fracture.
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Aprilia, Aprilia, Jin Lee Tan, Yongjing Yang, Sung Chyn Tan, and Wei Zhou. "Induction Brazing for Rapid Localized Repair of Inconel 718." Metals 11, no. 7 (2021): 1096. http://dx.doi.org/10.3390/met11071096.
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Vacuum furnace has been used for brazing repair of aerospace components, but it is a slow process which typically takes a few hours. The prolonged heating and cooling cycles could cause some adverse effects on the components such as excessive grain growth. A rapid brazing technique using induction coil was studied to evaluate its suitability for localized repair. Induction brazing of Inconel 718 was carried out using AMS 4777 brazing paste at different temperatures (950 °C, 1050 °C and 1150 °C ) for various durations (2 min, 10 min and 20 min). Microstructure and microhardness were evaluated. The experimental results show that brazing at 1050 °C leads to desirable microstructures in a short period of merely 2 min. The study demonstrates the potential application of induction brazing for rapid localized aerospace repair.
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Zhao, Bin, Yuanbin Fang, and Linjie Zhang. "Application of brazing process design in optimization structure design of scraper." MATEC Web of Conferences 175 (2018): 03017. http://dx.doi.org/10.1051/matecconf/201817503017.
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To effectively enhance the service life, the research of milling machine scraper structure design and welding process are optimized. Through the structural optimization analysis, the improved structure is obtained, and the working resistance force is reduced. The full factor test is used to optimize the brazing process, and the best parameters are obtained, which improves the shear strength. The accuracy of the model is verified by experiments. The results show that compared with the working resistance force, the improved scraper tends to be slow and the peak value is smaller. The cutting rake and relief angle of the scraper are optimized. When the cutting rake angle is 6° and the cutting relief angle is 9°, both working resistance force and impact force are minimum. It proves the accuracy of the simulation results. Using CT861 solder, brazing temperature is 75°C, and the brazing time is 10s. While the cooling method uses furnace cold, the minimum value of shear strength is 200MPa. The average working life of the scraper is raised from 800 hours to 1600 hours after the optimization design. Research results have guiding significance for the structure design and the welding process optimization of the scraper.
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Zhang, Ning, Jin Guo Ge, Li Yang, and Min He. "Development of Shearer Picks Brazed by Copper Brazing Agent and Property Study on Brazing." Advanced Materials Research 791-793 (September 2013): 710–13. http://dx.doi.org/10.4028/www.scientific.net/amr.791-793.710.
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As wearing parts, shearer picks, in which the huge consumption and inefficient are caused by the poor quality of brazing, are widely used in the mining process. In this paper, the cemented carbide YG15, 42CrMo steel and HL105 copper brazing film were used as the head, body and solder, respectively, and the furnace brazing was used for shearer picks where the home-made water-soluble copper brazing agent was fabricated instead of the traditional dehydrated borax. The results show that the strength of the welded joint improves greatly and is up to a superior level. When the copper brazing agent and water in a four-to-six ratio, the solder is completely wetted, the best bending resistance of the head is obtained, the brazing seam of picks which are superior to the factory production is brimming, and thus the service life is significantly improved.
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Duckham, A., J. Levin, and T. P. Weihs. "Soldering and Brazing Metals to Ceramics at Room Temperature Using a Novel Nanotechnology." Advances in Science and Technology 45 (October 2006): 1578–87. http://dx.doi.org/10.4028/www.scientific.net/ast.45.1578.
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This paper reviews a new, low-temperature process for soldering and brazing ceramics to metals that is based on the use of reactive multilayer foils as a local heat source. The reactive foils range in thickness from 40μm to 100μm and contain many nanoscale layers that alternate between materials with large heats of mixing, such as Al and Ni. By inserting a free-standing foil between two solder (or braze) layers and two components, heat generated by the reaction of the foil melts the solder (or braze) and consequently bonds the components. The use of reactive foils eliminates the need for a furnace, and dramatically reduces the heating of the components being bonded. Thus ceramics and metals can be joined over large areas without the damaging thermal stresses that are typically encountered when cooling in furnace soldering or brazing operations. This paper draws on earlier work to review the bonding process and its application to a variety of ceramic-metal systems. Predictions of thermal profiles during bonding and the resulting residual stresses are described and compared with results for conventional soldering or brazing processes. The microstructure, uniformity, and physical properties of the reactive foil bonds are reviewed as well, using several different ceramic-metal systems as examples.
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Miura, Hirokazu, Hiroki Okada, Yasuyuki Miyazawa, and Fumio Kanasaki. "In Situ Observation during Copper Alloy Brazing Using an X-Ray System." Materials Science Forum 1016 (January 2021): 911–16. http://dx.doi.org/10.4028/www.scientific.net/msf.1016.911.
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In general, a flux is used to braze a copper alloy. In many cases, when the molten brazing filler metal spreads in the set joint gap, vaporised flux and its residue are produced, and defects (mainly voids) are formed. Voids, which are formed on the brazed layer, cause deterioration in the strength and other properties. However, with conventional evaluation methods (e.g. ultrasonic or X-ray radiography tests), the behaviour of the molten brazing filler metal during the brazing process cannot be visually observed from the outside of the joint. Therefore, the void formation process cannot be clarified. To improve the quality of the brazed layer, it is necessary to elucidate the mechanism of void formation. The purpose of this study is to observe the behaviour of the molten brazing filler metal by performing an X-ray radiography test at the same time as brazing and to study how to reduce voids. In this study, a brass specimen was brazed with a Cu–P-based brazing filler metal. The specimen was brazed by heating in an electric furnace, and the specimen was irradiated with X-rays. The state where the molten brazing filler metal spread into the gap was photographed as the transmission image. Thereafter, the behaviour of the molten brazing filler metal was analysed.
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Pascal, Dragos Toader, Viorel Aurel Şerban, and Gabriela Marginean. "Optimization of Process Parameters for the Manufacturing of High Temperature Vacuum Brazed WC-NiCrBSi Coatings." Solid State Phenomena 254 (August 2016): 164–69. http://dx.doi.org/10.4028/www.scientific.net/ssp.254.164.
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Process parameters play a crucial role in the final characteristics and properties of every product. The current work focuses mainly on improving the vacuum furnace brazing process for tungsten carbide reinforced Ni-based alloy (NiCrBSi) metallic composite coatings, by establishing the best set of parameters adapted to this specific chemical composition. In order to determine the optimum parameters, a fine adjustment of a typical vacuum brazing process was performed. The melting interval of the filler metal was identified by means of Differential Thermal Analysis. Morphology, microstructure and metallurgical bond of the cladding to the substrate material were investigated by Scanning Electron Microscopy and Light Microscopy combined with a Porosity Analysis Software. The process optimization resolved the initial problem of fractures and crack initiation, making possible to achieve high quality hardfacing coatings with a low degree of porosity (approximately 1 %).
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Rezende, Renato Paulo, and Mauricio David Martins das Neves. "Microstructural Characterization of Joints of Inconel 718 Brazed on Vacuum Furnace." Materials Science Forum 1012 (October 2020): 354–59. http://dx.doi.org/10.4028/www.scientific.net/msf.1012.354.
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The spacer grids are part of the Fuel Element (FE) set of the PWR (Pressurized Water Reactor) type reactor. These grids maintain the position of the fuel rods within the arrangement of the FE, conserving among them the spacing necessary for the operation of the reactor. The grids are manufactured from the union of the intersecting points of stamped strips of Base Material (BM) Inconel 718, by a joint process called brazing. The addition metal (AM) used consists of a brazing paste based on Ni-Cr-P (nickel-chromium-phosphorus), which is added dropwise in the intersection of grids with a clearance of 0.025 mm. For this purpose, Inconel 718 smooth strips of 0.35 mm thick nickel plated samples were prepared, the AM was added and the vacuum oven was 10-3 mbar, in different time and temperatures. The samples were prepared by metallography and characterized using optical microscopy (OM), scanning electron microscopy (SEM) and mechanical microhardness test. The purpose of this work is to characterize the brazing joint by means evaluate the size of precipitates and the different compounds formed in the joint. It was found different precipitates composed mainly of titanium and niobium. Phosphorus rich phases were found in the brazed region. The mean hardness of the BM was 469 ± 12 HV and in the joint region hardness of 1345 ± 34 HV was found in the lighter phases.
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Hauschildt, Katja, Andreas Stark, Hilmar Burmester та ін. "Phase Transformations in the Brazing Joint during Transient Liquid Phase Bonding of a γ-TiAl Alloy Studied with In Situ High-Energy X-Ray Diffraction". Materials Science Forum 941 (грудень 2018): 943–48. http://dx.doi.org/10.4028/www.scientific.net/msf.941.943.
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TiAl alloys are increasingly used as a lightweight material, for example in aero engines, which also leads to the requirement for suitable repair techniques. Transient liquid phase bonding is a promising method for the closure of cracks (in non-critical or non-highly loaded areas). The brazing solder Ti-24Ni was investigated for brazing the alloy Ti-45Al-5Nb-0.2B-0.2C (in at. %). After brazing, the joint exhibits different microstructures and phase compositions. The transient liquid phase bonding process was investigated in the middle of the joint region in situ to acquire time resolved information of the phases, their development, and thus the brazing process. These investigations were performed using high-energy X-ray diffraction at the “High-Energy Materials Science” beamline HEMS, located at the synchrotron radiation facility PETRA III at DESY in Hamburg, Germany. For this, we used an induction furnace, which is briefly described here. During the analysis of the diffraction data with Rietveld refinement, the amount of liquid was refined with Gaussian peaks and thus could be quantified. Furthermore, while brazing four different phases occurred in the middle of the joint region over time. Additionally, the degree of ordering of the βo phase was determined with two ideal stoichiometric phases (completely ordered and disordered). Altogether, the phase composition changed clearly over the first six hours of the brazing process.
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Berezhnyy, Stanislav, Oleksii Kapustian, Ruslan Kulykovskyi, Ihor Avdeev, and Danylo Uriekin. "Development of resource-saving and environmentally safe beryllium bronze soldering technology." Scientific journal of the Ternopil national technical university 100, no. 4 (2020): 46–54. http://dx.doi.org/10.33108/visnyk_tntu2020.04.046.
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The composition of the solder, which provides the necessary technological properties of the product, namely, electrical conductivity and mechanical strength of the junction was selected. The possibility of brazing beryllium bronze with a silver contact plate by furnace brazing using fluxes based on NaCl: CaCl2: CaF2 salts, respectively (24: 61: 15% mass) in the atmosphere was established. The possibility of brazing BrB2 beryllium bronze in the atmosphere using a research flux based on the eutectic of the NaCl – CaCl2 system (28…72% wt.) adding 15% CaF2 over a copper layer is shown. The technology for brazing beryllium bronze BrB2 with silver contact plates with silver solder PSr68 has been developed. The brazing process is combined with the hardening operation, which allows avoiding additional thermal operations; flux residues are removed during hardening and do not actually need additional cleaning operations; applied solder, flux components and technologies for applying a layer of copper are not scarce and relatively cheap, which can significantly reduce the cost of the product, subject to the requirements of the technical specifications. A technological process that makes it possible to refuse of using vacuum systems and toxic fluxes has been developed.
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Molleda, F., J. Mora, J. R. Molleda, E. Carrillo, E. Mora, and B. G. Mellor. "Copper coating of carbon steel by a furnace brazing process using brass as the braze." Materials Characterization 59, no. 5 (2008): 613–17. http://dx.doi.org/10.1016/j.matchar.2007.05.005.
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Cheng, Dongfeng, Jitai Niu, Zeng Gao, and Peng Wang. "Vacuum brazing of high volume fraction SiC particles reinforced aluminum matrix composites." Modern Physics Letters B 29, no. 06n07 (2015): 1540002. http://dx.doi.org/10.1142/s0217984915400023.
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This experiment chooses A356 aluminum matrix composites containing 55% SiC particle reinforcing phase as the parent metal and Al – Si – Cu – Zn – Ni alloy metal as the filler metal. The brazing process is carried out in vacuum brazing furnace at the temperature of 550°C and 560°C for 3 min, respectively. The interfacial microstructures and fracture surfaces are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy spectrum analysis (EDS). The result shows that adequacy of element diffusion are superior when brazing at 560°C, because of higher activity and liquidity. Dislocations and twins are observed at the interface between filler and composite due to the different expansion coefficient of the aluminum alloy matrix and SiC particles. The fracture analysis shows that the brittle fracture mainly located at interface of filler and composites.
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Kabatskaia Ivanovna, Alla, Victor M. López-Hirata, Eduardo Oliva López, Ricardo Rodríguez Figueroa, and Jorge Rodríguez Miramontes. "Microstructural and Mechanical Characterization of Nitinol GTAW and FB Welds of Titanium." Materials Science Forum 509 (March 2006): 165–70. http://dx.doi.org/10.4028/www.scientific.net/msf.509.165.
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Microstructural and mechanical characterization of Nitinol gas tungsten arc weld (GTAW) and furnace brazing (FB) welds for grade 1 titanium plates are carried out in order to study the microstructure developed after welding and its effect on the mechanical properties of welds. The GTAW process yields the highest hardness weld. The constituents for this weld consist of a dendritic structure of NiTi and NiTi2 intermetallic phases. The FB process promotes a change of the welds chemical composition due to atomic diffusion of Ti. The weld microconstituents consist of a mixture of a Ti-rich and NiTi2 eutectic and a proeutectic Ti-rich phase.
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Pimenta, J. S., A. J. A. Buschinelli, R. M. do Nascimento, A. E. Martinelli, and J. Remmel. "Joining of zirconia mechanically metallized with titanium." Cerâmica 56, no. 339 (2010): 212–21. http://dx.doi.org/10.1590/s0366-69132010000300002.
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Direct brazing is a well-known technique for joining ceramics either themselves or to metals, whereby the required costly active filler alloys are considered a handicap of this process. In this work the indirect brazing of zirconia to zirconia mechanically metallized with Ti was successfully achieved using conventional filler alloys. The mechanical metallization specially applied to oxide ceramics is a successfully technique that was patented by Forschungszentrum Juelich, Germany, and it has been the subject of applied researches in the last 10 years. This particular metallization is made at room temperature with low cost production and is environmentally safe. Partially stabilized zirconia with yttria was mechanically metallized with Ti and wetting conditions were evaluated using Ag-28Cu and Au-18Ni fillers. These conventional fillers dissolve part of the Ti-coating becoming on-site at brazing temperature an active filler alloy which reacts with the zirconium oxide to improve wetting on the ceramic surface. Better results were selected for brazing tests in a high-vacuum furnace (< 3×10-5 mbar). Helium gas leak detection was made at the ceramic/ceramic interface at room temperature; samples from reliable vacuum tight joints were examined by microestructural analysis and linescan technique by energy dispersive X-ray analysis in its cross-section. Microhardness profiles were made across the joint interface where zirconia undergone darkening after brazing process. Sound brazed joints were produced even when just one ceramic surface of the joint assemble was previously metallized, due to titanium diffusion from the metallized ceramic surface to the other ceramic side at the joint assemble.
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Zhou, Yi, Chunzhi Xia, Jun Yang, Xiangping Xu, and Jiasheng Zou. "Investigation of the microstructure and properties of W75-Cu/W55-Cu brazed joint with Cu-Mn-Co filler metal." Science and Engineering of Composite Materials 25, no. 1 (2018): 17–23. http://dx.doi.org/10.1515/secm-2016-0003.
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AbstractW75-Cu and W55-Cu alloys were brazed with a Cu-based filler metal under the process parameters of a brazing temperature of 1060°C and a holding time of 30 min in a vacuum furnace with a vacuum level >6×10-3Pa. The microstructure, element distribution, phase constituents, four-point bending strength, and fracture morphology of the brazed joint were studied with a series of standard methods. The results indicated that the main microstructure of the brazing seam region was a Cu-based solid solution of Mn and Co dissolved in the Cu phase. The element Cu and a little element W from two sides of the base metals transited into the brazing seam region, and the elements Cu, Mn, and Co contained in the brazing filler metal diffused into the interface or even substrates. The main phases that existed in the brazed joint were Cu-rich phase Cu(Mn,Co), simple substance of W, simple substance of Cu, and trace amounts of Cu0.4W0.6. The four-point bending strength was about 950 MPa, and fracture occurred at the interface near the W75-Cu alloy side. The fracture morphology of the W75-Cu/W55-Cu brazed joint was identified as mixed ductile-brittle.
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Eivani, A. R., M. Ahmadian, and H. Vafaeenezhad. "Effect of process conditions on the evolution of microstructure and mechanical properties of AA3003 vacuum furnace brazing joints." Materials Research Express 7, no. 1 (2020): 016561. http://dx.doi.org/10.1088/2053-1591/ab66eb.
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Pimenta, Jean S., Augusto J. A. Buschinelli, Rubens M. do Nascimento, Augusto E. Martinelli, and Joseph Remmel. "Brazing of zirconia to titanium using Ag-Cu and Au-Ni filler alloys." Soldagem & Inspeção 18, no. 4 (2013): 349–57. http://dx.doi.org/10.1590/s0104-92242013000400007.
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Advanced ceramic is usually joined to metal by the well-known direct brazing process, where costly active filler alloys can be considered a limitation. Brazing using active-metal-free filler alloy as insert between the joint components is an attempt to overcome it. The active metal diffusion from the titanium member through the bulk of molten filler to the ceramic was responsible to produce an active filler alloy in loco and promote reduction of the zirconium oxide to improve wetting on the ceramic surface. Unalloyed titanium was joined in a high-vacuum furnace (<3x10-5 mbar) to yttria-tetragonal zirconia polycristals (Y-TZP) and zirconia partially stabilized with magnesia (Mg-PSZ), where commercial fillers Ag-28Cu and Au-18Ni with respective thermal cycles were evaluated. Helium gas leak detection test was performed at the ceramic/metal interface at room temperature; samples from reliable vacuum tight joints were examined by microstructural analysis techniques and energy dispersive X-ray analysis at the joint cross-section. Tight joints were produced with eutectic Ag-Cu filler, revealing an intermetallic layer and a dark reaction layer near the ceramic surface; titanium diffusion was efficient for superficial chemical interactions between individual components. Brazing joints were also tested using three-point flexure testing.
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Xia, C. Z., J. Yang, X. P. Xu, and J. S. Zou. "Microstructure and Properties of W–Cu Composite/Fe-Based Powder Alloy Vacuum Brazed Joint with Different Filler Metals." High Temperature Materials and Processes 36, no. 5 (2017): 477–83. http://dx.doi.org/10.1515/htmp-2015-0258.
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AbstractW–Cu composite and Fe-based powder alloy were brazed with filler metals of Ag–Cu and Cu–Mn–Co alloys in a vacuum furnace. Both of filler metals can join W–Cu composite with Fe-based powder alloy directly in the experiment process. Microstructure, distribution of elements and fracture morphology were observed and analyzed using scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) methods, and phase composition of bonding area was analyzed by X-ray diffraction (XRD). The obtained results indicated that the smooth faying surface and dense microstructure of brazed joint were formed and the primary microstructure of brazing seam were, respectively, Ag(Cu) solid solution and Cu(Mn) solid solution, which ensured forming the stable connection of brazed joint. The bending strength of Ag-based and Cu-based brazed joint can, respectively, reach to 317 and 704 MPa, where fracture showed a typical ductile fracture characteristic. The fracture of Cu-based brazed joint located at brazing seam area, and the fracture of Ag-based brazed joint occurred in Fe-based powder alloy side.
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Zhang, Ning, Na Shi, Min He, Feng Yang, and Hao Chen. "Study on Wear Behavior of Plasma Arc Cladding of Tunneling Machine Pick." Advanced Materials Research 886 (January 2014): 105–8. http://dx.doi.org/10.4028/www.scientific.net/amr.886.105.
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The working environment of tunneling machine is very harsh. In the high-impact, high-stress, and high abrasion conditions, the cutting pick is a large number of wearing parts in the tunneling process. In this experiment, the tooth head of the cutting pick which was welded by furnace brazing was strengthened by plasma arc powder surfacing with F30 alloy powder, then analyse the surface topography and component, the hardness distribution from the surfacing layer to the interior of the matrix, the friction and wear properties of the surfacing layer, study the microstructure of grinding marks, and the wear mechanism. So as to improve the wear resistance of the cutting pick, to solve the wear failure, and provide a good reference for extending the service life.
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Sun, Feng Lian, Feng Gu, Zhi Li Zhao, and Heng Ze Xian. "Microstructure in the Interface between CVD Diamond Thick Film and a Ag-Cu-Ti Braze Alloy." Key Engineering Materials 353-358 (September 2007): 1999–2002. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.1999.
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CVD diamond thick film was brazed to cemmented carbide using a Ag-Cu-Ti active filler metal. The brazing process was performed in a vacuum furnace under different processing condition. The interfacial microstructure and characterization between diamond and Ag-Cu-Ti filler metal were studied by SEM, EPMA and EDX. The morphology and distribution of new compound are shown for the first time (Figs). Results illustrate that a small amount of new compound TiC, TiCu compound exist in the interface. TiC layer exists in the interface and it's thickness is variational with the varying of processing condition such as peak heating temperature, keeping time and so on. New compound TiC accretes with the surface atoms of diamond in a special section, and particular orientation relationships are occasionally observed by examining the fracture section. TiCu layer near TiC exists in the interface. It is worth notice that too much TiC and TiCu in interface could weaken join strength because TiC and TiCu are brittle.
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Weirauch, Douglas A., and Stephen F. Horvath. "The Spreading Kinetics of Ag–28Cu(L) on Nickel(S): Part II. Area of Spread on Surfaces Plated with Electrolytic Ni." Journal of Materials Research 12, no. 4 (1997): 953–64. http://dx.doi.org/10.1557/jmr.1997.0136.
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Furnace brazing is commonly used in the electronic industry to attach I/O pins, lid-seal rings, and heat spreaders to cofired multilayer ceramic packages. Despite the widespread industry usage of electrolytic and electroless Ni coatings to render base metal surfaces wettable by braze fillers, there is no fundamental treatment of “brazeability” in the published literature that can be used by the materials technologist to design coatings for a given application. In this study, dynamic hot stage microscopy is used to establish the parameters that control the spreading of eutectic Ag–Cu braze on surfaces plated with electrolytic Ni. The effects of plating thickness, substrate type, plating annealing, and the braze thermal cycle are considered. A braze spreading mechanism developed for polycrystalline Ni foil in Part I of this study is linked to Ni-plated surfaces through consideration of differences in microstructure. Eventual extension of this improved understanding to surfaces plated with electroless Ni–B and Ni–P deposits will result in shortened product design time and improved manufacturing process control.
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Lee, H. K., Chung Yun Kang, C. S. Woo, S. H. Kim, and Dae Up Kim. "Interfacial Morphology of Duplex Stainless Steel Joints Brazed with Ni-Cr-Si-B Filler Metal." Materials Science Forum 449-452 (March 2004): 889–92. http://dx.doi.org/10.4028/www.scientific.net/msf.449-452.889.
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Microstructures of 0.18wt% nitrogen-contained duplex stainless steel, SUS329J3L brazed in a vacuum furnace of 10-4torr, have been investigated as a function of bonding temperatures (1453-1523K) and holding times (0-1.8ks). An amorphous alloy, MBF50 (Ni-19.5wt%Cr-7.3wt%Si -1.5wt%B), was used as an insert metal. At an early stage at 1453K and 1473k, a morphology change of the insert metal, BN and CrB phase appeared only at the joints. The BN and Cr-Si-N phase were observed at the interface of the joints brazed under other conditions. The volume fraction of BN increased rapidly at an early stage and decreased with increasing holding time. The phase seemed to have been formed by dissolution of the base metal and the diffusion process. BN was formed easily due to the lowest Gibbs free energy. Boron content in liquid insert metal becomes low due to the formation of a large number of BNs at the bonded interlayer by holding for a few minutes at brazing temperature. This caused the rapid isothermal solidification of the liquid insert metal. Thus, it is clear that the isothermal solidification process of this bonding is controlled by the formation of boron nitrides as opposed to the diffusion process of depressant elements(B and Si) in the base metal.
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Andrade de Castro, Luiz Fernando, Roberto Parreiras Tavares, and Varadarajan Seshadri. "PROCESS CONTROL MODEL FOR CHARCOAL BLAST FURNACES IN BRAZIL." Materials and Manufacturing Processes 20, no. 2 (2005): 287–98. http://dx.doi.org/10.1081/amp-200042085.
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Mucsi, Cristiano Stefano, L. A. M. dos Reis, Maurilio Pereira Gomes, L. A. T. Pereira, and Jesualdo Luiz Rossi. "Study on the Viability of the Recycling by Electric Arc Melting of Zirconium Alloys Scraps Aiming the Scalability of the Process." Materials Science Forum 930 (September 2018): 495–500. http://dx.doi.org/10.4028/www.scientific.net/msf.930.495.
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Turning chips of zirconium alloys are produced in large quantities during the machining of alloy rods for the fabrication of the end plugs for the Pressurized Water Reactor (PWR) fuel elements parts of Angra II nuclear reactor (Brazil – Rio de Janeiro). This paper presents a study on the search for an efficient way for the cleaning, quality control and Vacuum Arc Remelting (VAR) of pressed zirconium alloys chips to produce a material viable to be used in the production of the fuel rod end plugs. The process starts with cutting oil clean out. The first step in this process consists in soaking a bunch of chips in clean water, to remove soluble cutting oils, followed by an alkaline degreasing bath and a wash with a high-pressure flow of water. Drying is performed by a flux of warm air. The oil free chips are then subjected to a magnet in order to detect and collect any magnetic material, essentially ferrous, that may be present in the original chips. Samples of the material are collected and then melted in a small non consumable electrode vacuum arc furnace for evaluation by Energy Dispersive X-ray Fluorescence Spectrometry (EDXRFS) in order to define the quality of the chips. The next step consists in the 15 ton hydraulic pressing the chips in a die with 40 mm square section and 500 mm long, producing an electrode with 20% of the Zircaloy bulk density. The electrode was finally melted in a laboratory scale modified VAR furnace located at the CCTM–IPEN, producing 0.8 kg ingots. The authors conclude that the samples obtained from the fuel element industry can be melting in a VAR furnace, modified to accommodate low density electrodes, allowing a reduction up to 40 times the original storage volume, however, it is necessary to remelt the ingots to correct their composition in order to recycle the original zirconium alloys chips. in a process to reduce volume and allow the reutilization of valuable Zircaloy scraps.
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Gomes, Jerônimo Moraes, Ana Luiza Folchini Salgado, and Dachamir Hotza. "Life Cycle Assessment of Ceramic Bricks." Materials Science Forum 727-728 (August 2012): 815–20. http://dx.doi.org/10.4028/www.scientific.net/msf.727-728.815.
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Ceramic bricks are one of the most widely used materials in both commercial and residential buildings. Ceramic bricks play a relevant role in the Brazilian economy. The basic input material for this industry is red clay. As environmental problems increase, the need for environment-friendly building design increases. To achieve this, architects and engineers need reliable data on the environmental impacts of various building materials, including ceramic bricks. In this paper a comparative Life Cycle Assessment between two ceramic brick production units in Santa Catarina State, Brazil, has been carried in a comparative approach. Key impact categories, including fossil fuel use, global warming, ozone depletion, ecotoxicity, and human toxicity were assessed. The analysis has shown a particular relevance of the respiratory effects in both systems and the critical point has been found in the fuel used in the furnace for firing the bricks which are responsible, during the ring process, for the relevant CO2 emissions.
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Pontes, Henrique, Luiz Fernandes, Mário de Melo, Gilson Guimarães, and Laís Massuqueto. "Speleothems in quartz-sandstone caves of Ponta Grossa municipality, Campos Gerais region, Paraná state, southern Brazil." International Journal of Speleology 49, no. 2 (2020): 119–36. http://dx.doi.org/10.5038/1827-806x.49.2.2313.
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The present communication characterizes and discusses the genesis of cave speleothems developed in Furnas Formation (Silurian-Devonian) and Vila Velha sub-unit (Campo Mourão Formation, Upper Carboniferous) quartz-sandstones, in southern Brazil. The research, which involved stratigraphic and petrographic studies, was conducted to identify the faciological context of occurrence of these features, and to determine, through different analytical methods, their mineralogical composition and porosity, and also the action of microbial markers on the genesis of these secondary mineral deposits. The speleothems were classified into six types based on form, composition and genesis: (1) arborescent (coral), (2) mushroom-shaped, (3) stalactitic, (4) stalagmitic, (5) columnar with horizontal/ascending growth, and (6) fibrous. In response to substrate permoporosity, speleothems develop on all sandstone facies of the study area, mainly in sites controlled by bedding, stratification and fracturing planes. They are less frequent, however, in conglomerate and silty-clayey layers of the Furnas Formation, being composed mainly of silica (opal-A and cryptocrystalline silica) and kaolinite, with lesser contribution of gypsum and amorphous iron oxides associated with goethite and hematite. Detritic minerals such as quartz and muscovite also take part in the composition of these features. Plant and invertebrate fragments were identified, including biosignatures and microorganisms capable of favoring precipitation of silica (possibly cyanobacteria and diatom) and iron oxide (possibly Gallionella ferruginea). Such biosignatures and extracellular polymeric substances (biofilms) associated with speleothems are evidence of organomineralization, also known as biologically induced mineralization. The results, which indicate biological action on the genesis of speleothems, raise further discussion on the influence of microorganisms on the dissolution and precipitation of silica and kaolinite in the region.
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Monteiro, Thiago Campos, Renato Vieira da Silva, José Tarcísio Lima, Paulo Ricardo Gherardi Hein, and Alfredo Napoli. "Use of near infrared spectroscopy to distinguish carbonization processes and charcoal sources." CERNE 16, no. 3 (2010): 381–90. http://dx.doi.org/10.1590/s0104-77602010000300014.
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The near infrared spectroscopy (NIRS) has shown a rapid and accurate technique for evaluation of materials of biological origin. The objective of this study was to evaluate the ability of the near infrared (NIR) spectroscopy associated to the Principal Component Analysis (PCA) for the separation of carbonization processes and identification of the origin of the woods used in the carbonizations. Hence, the charcoal of seven species of Eucalyptus and twenty native species from the Cerrado (savannah) of Minas Gerais, Brazil were investigated. The Eucalyptus wood was carbonized in a laboratory furnace and in a 190 m³ industrial rectangular kilns while the wood of native vegetation was carbonized only under laboratory conditions. The samples were grinded for NIR spectra acquirement. The NIR spectra were analyzed by PCA but no cluster were identified allowing discrimination between charcoal produced from native and from Eucalyptus wood. However, the cluster formed in the PCA when using the first derivative NIR spectra permitted to distinguish charcoal produced in different processes of carbonization. Two groups of data for charcoal produced in the industrial rectangular kilns were also observed, suggesting heterogeneity in the carbonization process.
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Melo, Mário Sérgio de, Gilson Burigo Guimarães, Adilson Luiz Chinelatto, et al. "Kaolinite, illite and quartz dissolution in the karstification of Paleozoic sandstones of the Furnas Formation, Paraná Basin, Southern Brazil." Journal of South American Earth Sciences 63 (November 2015): 20–35. http://dx.doi.org/10.1016/j.jsames.2015.06.011.
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Silva, Givanilda Honório, Miguel Ysrrael Ramírez-Sánchez, and Rodrigo Florencio da Silva. "Caracterización de la Contaminación Atmosférica por Calcinación de Yeso en los Municipios de Araripina y Trindade, Noreste de Brasil." Ensaios e Ciência: Ciências Biológicas, Agrárias e da Saúde 23, no. 3 (2019): 203. http://dx.doi.org/10.17921/1415-6938.2019v23n3p203-212.
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ResumenEste manuscrito presenta a través de un estudio tipo no experiemental la caracterización de la contaminación atmosférica por la calcinación de yeso en los municipios de Araripina y Trindade del estado de Pernambuco, en el noreste de Brasil. Esos municipios son importantes por conformar el Complejo Yesero de Araripe que representa la mayor parte de la producción de yeso de Brasil, considerada una de las mayores del mundo. La investigación se realizó utilizando datos de informes de pruebas de caracterización de emisiones atmosféricas realizadas en 20 empresas, 9 de Trindade y 11 de Araripina, de 2015 a 2018. Según los resultados, no hubo una reducción significativa en las emisiones de contaminantes entre 2015 y 2016, lo que evidencia pocas inversiones en el mantenimiento y mejora de los procesos. Sin embargo, para el período 2017-2018, los datos muestran una disminución en las emisiones de contaminantes, con un número considerable de empresas que cumplen con los límites establecidos por la ley. Dado lo anterior, existe la necesidad de intensificar la supervisión de las empresas de yeso en la región debido los hornos se encuentran en condiciones precarias sin mantenimiento y mejora en el proceso de combustión donde las emisiones de monóxido de carbono y otros contaminantes que exceden en mucho el límite permitido por la legislación ambiental. Palabras-clave: Contaminación del aire, Residuos de yeso, Análisis isocinético. AbstractThis manuscript presents through a non-experimental type study, the characterization of air pollution by the calcination of plaster in the municipalities of Araripina and Trindade in the state of Pernambuco, in northeastern Brazil. These municipalities are important for shaping the Plaster Complex of Araripe, which represents the majority of the plaster production in Brazil, considered one of the largest in the world. The research was conducted using data from reports of atmospheric emissions characterization tests carried out in 20 companies, 9 from Trindade and 11 from Araripina, from 2015 to 2018. According to the results, there was no significant reduction in pollutant emissions between 2015 and 2016, which shows few investments in the maintenance and improvement of the processes. However, for the 2017-2018 period, the data shows a decrease in pollutant emissions, with a considerable number of companies that meet the limits established by law. Given the above, there is a need to intensify the supervision of gypsum companies in the region because the furnaces are in precarious conditions without maintenance and improvement in the combustion process where emissions of carbon monoxide and other pollutants that greatly exceed the limit allowed by environmental legislation.Keywords: Atmospheric pollution, Plaster waste, Isokinetic analysis.
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Kawakami, Kosuke, Hirokazu Kobayashi, and Kazuhide Nakata. "Seasonal Inventory Management Model for Raw Materials in Steel Industry." INFORMS Journal on Applied Analytics 51, no. 4 (2021): 312–24. http://dx.doi.org/10.1287/inte.2021.1073.
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We developed a seasonal inventory management model for raw materials, such as iron ore and coal, for multiple suppliers and multiple mills. The Nippon Steel Corporation imports more than 100 million tons of raw material annually by vessels from Australia, Brazil, Canada, and other countries. Once these raw materials arrive in Japan, they are transported to domestic mills and stored in yards before being treated in a blast furnace. A critical problem currently facing the industry is the limited capacity of the yards, which leads to high demurrage costs while ships wait for space to open up in the yards before they can unload. To reduce the demurrage costs, the inventory levels of the raw materials must be kept as low as possible. However, inventory levels that are too low may lead to inventory shortage resulting from seasonal supply disruptions (e.g., a cyclone in Australia) that delay the supply of raw materials. Because both excess and depleted inventory levels lead to increased costs, optimal inventory levels must be determined. To solve this problem, we developed an inventory management model that considers variations on the supply side, differences that should be observable upon looking at the ship operations. The concept is to model the probability distribution of ship arrival intervals by brand groups and mills. We divided ship operations into two stages: arrival at all mills (in Japan) and arrival at individual mills. We modeled the former as a nonhomogeneous Poisson process and the latter as a nonhomogeneous Gamma process. Our proposed model enables inventory levels to be reduced by 14% in summer and 6% in winter.
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Rezende, Raphael Nogueira, José Tarcísio Lima, José Reinaldo Moreira da Silva, Alfredo Napoli, Hélder Bolognani Andrade, and André Luiz Raimundo Faria. "Air drying of logs from an Eucalyptus urophylla clone for carbonization use." CERNE 16, no. 4 (2010): 565–72. http://dx.doi.org/10.1590/s0104-77602010000400016.
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Wood drying is one of various stages in the carbonization process, therefore proper monitoring is key to improving yield and obtaining quality charcoal. Prior to being subjected to carbonization by charcoal production plants and once trees have been felled, logs are piled up by the roadside or close to carbonization furnaces and left air drying for 90 days until an optimal 30% moisture content is reached. This work aims to evaluate air drying of logs from an Eucalyptus urophylla clone for carbonization use, analyzing moisture reduction over time and also the influence of log diameter and bark. Logs with and without bark were used, 6.0cm to 21.0cm in diameter, 3.60m in length, with average basic density of 0.496 g/cm³, obtained from a commercial stand of Eucalyptus urophylla at age 8 years. Air drying log piles were arranged outdoors in Paraopeba, Minas Gerais State, Brazil and monitoring consisted of periodic log weighing for a period of 80 days. At the end of the experiment, higher rates of moisture loss were observed in the three initial weeks. Moisture in logs without bark (54%) and with bark (50%) was close after 80 drying days, with a higher level of moisture reduction being observed for logs without bark. Bark influence on moisture loss was more pronounced in the first three weeks. Moisture reduction varied in intensity as a function of log diameter. After 80 days, the highest level of moisture reduction was observed in logs without bark: 65% for logs larger in diameter and 80% for logs smaller in diameter. As regards logs with bark, results were 56% and 75% respectively.
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Samandi, M., M. Bate, R. Donnan, and S. Miyake. "Microwave Induced Plasma (MIP) Brazing of Silicon Nitride to Stainless Steel." MRS Proceedings 430 (1996). http://dx.doi.org/10.1557/proc-430-113.
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AbstractIn an attempt to accelerate the process of joining of metals to ceramics, a new rapid brazing technology has been developed. In this process, referred to as Microwave Induced Plasma (MIP) brazing, a microwave plasma is used to rapidly heat the ceramic and metal to the melting temperature of the reactive braze material. The heating rate obtained by MIP could be many times faster than those achieved by conventional resistive heating in a tube furnace. The fast heating rate has no detrimental effect on the joint quality and in fact results in the formation of a thick interfacial film suggesting significant interdiffusion between the braze and ceramic, possibly stimulated by the microwave radiation. In this paper the experimental arrangement of the MIP system is described. The unique capability of the MIP heating is demonstrated by successful joining of hot pressed silicon nitride to stainless steel using reactive metal brazing. The results of microstructural characterisation of the joints carried out by SEM and EDS will also be presented.
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Wilkenhoener, R., H. P. Buchkremer, D. Stoever, D. Stolten, and A. Koch. "Heat-Resistant, Electrically Conducting Joint Between Ceramic end Plates and Metallic Conductors in Solid Oxide Fuel Cell." MRS Proceedings 575 (1999). http://dx.doi.org/10.1557/proc-575-295.
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ABSTRACTCeramic parts made of doped lanthanum chromite are used as interconnects and end plates in stacks for several solid oxide fuel cell (SOFC) designs. Metallic conductors have to be attached to enable a low-resistance connection between individual stacks in each SOFC unit and to permit power to be drawn from the SOFC. The resistances of the metal-ceramic bond and the metallic conductors have to be stable under operating conditions, i.e., 1000°C in air. Consequently, heat-resistant materials have to be used. A two-step process has been developed to connect commercially available, Ni- or Febased metallic conductors to ceramic SOFC end plates by vacuum furnace brazing. In the first step, a metallic sheet, which acts as the current collector, is brazed onto the ceramic end plate. Thereby, the much lower electrical conductivity of the ceramic part is compensated by that of the metal. The chromium alloy CrFe5Y2O31 is suitable because it is heat-resistant, and its thermal expansion coefficient is close to that of lanthanum chromite. In the second step, metallic wires or strips are brazed on the current collector. Since this joint area is significantly smaller than that of the first joint, materials with a different thermal expansion coefficient can be used, such as conventional heat-resistant nickel alloys (Inconel 617) and ferritic stainless steels (FeCrAl 25 5). Filler alloys for both brazing steps with matching melting points have been found. Hence, both brazing steps can be performed cost-effectively in one heating step. Suitable parameters for vacuum furnace brazing of both joints are presented, and the composition of the filler alloys is given. Data concerning the long-term behavior of the joint resistances in air at 1000'C are discussed.
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Nagy, Douglas, and Robert Tollett. "Durable Abrasive Tip Design for Single Crystal Turbine Blades." Journal of Engineering for Gas Turbines and Power 143, no. 4 (2021). http://dx.doi.org/10.1115/1.4049823.
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Abstract In order to create and maintain peak efficiency in turbine stages, it is useful to minimize hot air leakage over blade tips. For unshrouded blades, this means creating minimal clearance over the airfoil tip with rub-tolerate zero-gap materials systems. In this study, a refractory abrasive tip material (ABT) was developed and applied to a plain turbine blade tip to work in conjunction with an abradable coating on the tip-shoe. Process development efforts resulted in abrasive material that could be as much as 2 mm thick. Further, the abrasive media included imbedded grits that would remain in back-up until such time as they were exposed and were pressed into service. Application methods of both furnace brazing and induction brazing were explored as were pre- and post-consolidation net shaping. Evaluation testing included compatibility for the application process onto single-crystal blades. Performance testing included rub-rig testing and long-term oxidation testing. Service testing included commercial engine operation for 14,000 h followed by metallurgical reevaluation. Service performance was mechanically successful, although some material transfer from the tip-shoe was observed which decreased the abrasive nature of the tip. Metallurgically, some intergranular oxidation was observed, but the grits themselves were well retained and were sufficiently refractory to avoid microstructural or oxidation degradation. A production implementation of the coating by an induction heating process is shown.
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Picanço, Miguel Brito. "CASA DO FORNO: instituição sócio-alimentar de Araí e Taiassuí, nordeste paraense." AntHropológicas Visual 3, no. 4 (2018). http://dx.doi.org/10.51359/2526-3781.2018.236570.
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Sinopse:A casa do forno (em outros lugares do Brasil é chamada de casa de farinha) é um dos elementos mais importantes no processo produtivo que permite que a mandioca se transforme em um conjunto de bens alimentícios, como: farinha d’água, goma, tucupi, etc., que são comidas (usa-se o termo comidas e não alimentos para reforçar o traço de sociabilidade proporcionado pela comida em situações coletivas, como comensalidade) que povoam os mercados e as mesas dos habitantes do nordeste paraense e que conferem considerável importância histórica, econômica, social e religiosa no lugar. (Picanço, 2018). Desse modo, a casa do forno, materializa-se em um espaço fulcral para a história da mandioca e dos habitantes de Araí e Taiassuí (comunidades rurais e produtoras de roça de mandioca no nordeste paraense), pois, ao mesmo tempo em que se constitui em um lugar onde são “paridos” todos os descendentes da mandioca, ela também funciona como um espaço de trocas de experiências, onde o saber fazer as comidas oriundas da mandioca é ensinado, aprendido e mantido de geração em geração. As casas do forno ajudam na composição socioespacial de Araí e Taiassuí, pois onde tem uma roça, nas proximidades também se encontra uma delas. Por isso, a casa do forno, ao mesmo tempo em que é pensada e concebida como uma instituição socioalimentar, também é compreendida como uma “maternidade”, um laboratório onde os frutos da mandioca são paridos, são nascidos. Como diria Marcena (2012, p. 52), ela é o “ventre da farinha, nascedoura de todas as farinhas de mandioca preparadas e também dos beijus [...], a casa de farinha se constitui como uma instituição socioalimentar [...], desde os primórdios da invenção da brasilidade [...].” Ela também se revela um lugar de interações sociais e sociabilidades que são alimentadas em um extenso fluxo de pessoas, de distintas famílias que ali trabalham em cooperação, mas também conta com a labuta dos não humanos, que ao mesmo tempo em que são singulares, tornam-se complexos, os quais não estão simplesmente ali, eles habitam naquelas casas do forno, onde desempenham atividades laborais específicas (Velthem, 2007), das quais a mandioca depende para gerar seus frutos. São eles e elas: a gamela grande, a gamela pequena, a mão de pilão, a peneira, a prensa, as vassouras, os tipitis, os rodos, o forno e, em alguns casos, o ralo e/ou o catitu, sobre os quais “[...] há [...] nítida percepção de que trabalham” (Velthem, 2007, p. 622). Portanto são das experiências laborais, dos humanos e não humanos, que dão vida aos descendentes da mandioca na casa do forno, que “falam” as imagens deste ensaio fotográfico. sinopsis:The furnace house (in other places of Brazil and called flour house) is one of the most important elements in the production process that allows cassava to become a set of foodstuffs, such as: water flour, gum, tucupi, etc., which are foods ( the term food is used to reinforce the sociability trait provided by food in collective situations such as commensality) that populate the markets and tables of the inhabitants of northeastern Pará and that confer considerable historical, economic, social and religious importance in the place. (PICANÇO, 2018). In this way, the furnace house is materialized in a central space for the history of cassava and the inhabitants of Araí and Taiassuí (rural communities and producers of cassava in northeastern of Pará), since, at the same time, in a place where all the descendants of cassava are "born", it also functions as a space for exchange of experiences, where the know how to make the foods from cassava is taught, learned and maintained from generation to generation. The furnace houses help in the socio-spatial composition of Araí and Taiassuí, because where there is a garden, there is also one nearby. For this reason, the furnace house, at the same time as it is thought and conceived as a socio-alimentary institution, is also understood as a "maternity", a laboratory where the fruits of cassava are born. How could say Marcena (2012, p. 52), it is the "belly of flour, born of all prepared cassava flour and also of the beijus [...], the flour house constitutes as a socio-alimentary institution...], from the earliest days of the invention of Brazilianness. It also reveals itself as a place of social interactions and sociabilities that are nurtured in an extensive flow of people, from distinct families who work there in cooperation, but also relies on the toil of not human, who at the same time are singular, make (VELTHEM, 2007), on which cassava depends to produce its fruits. They are: large trough, small trough, the hand of pestle, sieve, press, brooms, tipitis, rodos, furnace and, in some cases, drain and / or catitu, over which "[...] there is a clear perception that they work" (VELTHEM, 2007, p.622). Therefore, it is from the human and not human labor experiences that give life to the descendants of cassava in the furnace house that "speak" the images of this photographic essay.Palabras-chave:Casa do forno. Mandioca. Pará.Key-words:Furnace house. Cassava. Pará.Ficha técnica:Autora:Miguel de Nazaré Brito PicançoFotografias: Miguel de Nazaré Brito PicançoDireção, Edição de Imagem e Texto: Miguel de Nazaré Brito PicançoFicha técnica:Autora:Miguel de Nazaré Brito PicançoFotografía:Miguel de Nazaré Brito PicançoDirección:Miguel de Nazaré Brito Picanço
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Lense, Guilherme Henrique Expedito, Fernanda Almeida Bócoli, Rodrigo Santos Moreira, and Ronaldo Luiz Mincato. "Prediction of water erosion in a watershed located in southeastern Brazil." Revista Agrogeoambiental 12, no. 4 (2021). http://dx.doi.org/10.18406/2316-1817v12n420201504.
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Water erosion modeling is a fast and accurate way to estimate erosion potential in watersheds. Among the models, we have the Revised Universal Soil Loss Equation (RUSLE) which has a simple structure, low implementation cost and can be used with readily available information, contributing to the planning of soil conservation practices. In this context, the objective of the work was to apply RUSLE to estimate water erosion in the Córrego da Laje watershed affluent directly from the reservoir of the Furnas Hydroelectric Plant, located in the south of Minas Gerais, a region of southeastern Brazil. In this region, water erosion is a serious problem that has caused the silting up of the hydroelectric reservoir and the depreciation of water quality. Soil losses were calculated in Geographic Information System based on topographic, edaphoclimatic characteristics, soil cover, and management practices. The average soil loss of the watershed was 26.80 Mg ha-1 year-1 with the predominance of highintensity erosive rates (> 15 Mg ha-1 year-1). Considering the basin use classes, sediment generation was higher in pasture areas (35.87 Mg ha-1 year-1), and in areas under maize cultivation (32.05 Mg ha-1 year-1). As areas with severe erosion are distributed throughout the watershed, a comprehensive water erosion mitigation plan should be adopted to reduce the environmental damage of the process.
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Viltus, Joël, and Marcel De Souza Bonfim. "Favorability mapping of hydrotermal vein-type lead deposits: a case study in Ribeira Valley, Brazil." Revista do Instituto Geológico 39, no. 3 (2018). http://dx.doi.org/10.33958/revig.v39i3.602.
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The region of the Ribeira Valley is known for its metallic sulphide deposits (lead, zinc, copper, silver and gold), being the major lead producer of the Brazil in the 1950s. Since then, it has become the target of several geological studies from which two models of lead and zinc mineralization known as Perau and Panelas models were proposed. This study is particularly interested in the Panelas model, which is characterized by its vein morphology, association with carbonate rocks and structural control. Based on literature, this paper proposes to verify the applicability of the hierarchical analysis process (AHP) as auxiliary of the geographic information system (GIS) in the favorability mapping of hydrothermal veins-type Pb deposits which fit in the Panelas model. The study area is the western region of the Ribeira Valley, located in the southern portion of the São Paulo State, Brazil. In order to perform this work, four parameters were used: geological structure, stratigraphy, lithology and geochemistry. The result obtained highlights areas corresponding to Mina de Furnas, Bairro da Serra and Água Clara Formations as highly favorable areas to lead mineralization according this model. In addition, it shows the negative association of these geological formations with potassium concentration.
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De Melo, Rômulo R. R., Paula N. Coelho, Maria J. Dos Santos-Wisniewski, Célio Wisniewski, and Cristiana S. Magalhães. "Morphological abnormalities in cladocerans related to eutrophication of a tropical reservoir." Journal of Limnology, October 27, 2016. http://dx.doi.org/10.4081/jlimnol.2016.1395.
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<p>In zooplankton communities, morphological changes in Cladocera (Crustacea: Branchiopoda) may be resulting from water pollution by anthropogenic activities and/or natural events. The removal of vegetation cover, urbanization, agriculture and sewage release accelerate the eutrophication process in the aquatic environment. The present study seeks to demonstrate the occurrence of morphological abnormalities<strong> </strong>in cladocerans and relate the changes in the morphology and species composition to the physical and chemical parameters of the water. Samplings were made monthly in five stations on the Sapucaí River compartment of Furnas Reservoir, located in the state of Minas Gerais, Brazil, from July 2013 to February 2014. The Furnas Reservoir has intense occupation of the surrounding areas by agriculture, urban and industrial activities and the installation of net cage fish cultures, which contribute to the water quality deterioration. Cladocerans samples were collected using a suction pump and plankton net (68 μm mesh size) and concentrated from a volume of 400 L. The measures of physical and chemical parameters of the water were obtained by a Horiba U-50 multi-sensor on the surface of water column and the density and morphology of Cladocera were made by microscopy. Twenty-three species of Cladocera were recorded with high organism densities of Chydoridae family species. Morphological abnormalities were observed in <em>Daphnia gessneri</em>, <em>Ceriodaphnia silvestrii</em>, <em>Bosmina longirostris</em>, <em>Bosmina tubicen</em> and <em>Chydorus pubescens.</em> The highest densities of <em>C. pubescens</em> with abnormalities were observed at sampling stations which had littoral characteristics and influences of sewage release. For <em>C. pubescens</em>, abnormalities were observed and classified into two types. The type 1 abnormality was considered an increase of length of intestine and size of its intestinal loop, whereas for type 2 was considered the occurrence of an intestine prolapse. The morphological abnormalities in cladocerans were described and compared to the ones described in the literature. From the results, it may observe that the abnormalities were probably resulting from continuous eutrophication process which has been occurring in the reservoir due to anthropogenic activities around the reservoir and a decrease in the water volume of the reservoir, caused by an unusual dry weather period in this region in the last years.</p>