Papers by Keyword: Copper (Cu)

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Authors: Dong Nyung Lee
Abstract: Vapor-, electro-, and electroless-deposits have usually strong fiber textures. When annealed, the deposits undergo recrystallization or abnormal grain growth to reduce their energy stored during deposition. The driving force for recrystallization is mainly caused by dislocations, whereas that for abnormal grain growth is due to the grain boundary, surface, interface, and strain energies. During recrystallization and abnormal grain growth, the texture change can take place. The recrystallization and abnormal grain growth textures are in general of fiber type. However, copper interconnects are subjected to non-planar stress state due to geometric constraints during room temperature and/or elevated temperature annealing. The annealing textures of the thin films and copper interconnects are discussed in terms of the minimization of the surface, interface, and strain energies, the grain boundary energy and mobility, and the strain-energy-release maximization.
Authors: Wan Chuan Qiu, Xing He Yang, Di Hua Wang, Jin Yun Zou
Authors: Cornelia Prinz, Hans Georg Neumann
Abstract: The antibacterial effects of titanium oxide/calcium phosphate and calcium phos-phate/copper phosphate composite coatings have been investigated. Implant-like rough blasted tita-nium substrates are covered by a native titanium oxide layer. Together with the electrodeposited calcium phosphate layer a clear antibacterial effect has been observed. Electrodeposited calcium phosphate coatings were also dipped in aqueous copper sulphate solutions to convert partly calcium phosphate to copper phosphate. The antibacterial properties of such coatings can be controlled and adjusted to the clinical setting and to specific indications. Patient-tailored antibacterial treatments seem to be possible and may be of special interest for high-risk operations.
Authors: Ki Young Yoon, Jeong Hoon Byeon, Byung Ju Ko, Jae Hong Park, Chul Woo Park, Jung Ho Hwang, Hee Seung Yoon
Abstract: Copper (Cu) and silver (Ag) known as antimicrobial materials were deposited on activated carbon fibers (ACF) by an electroless plating method. The metal deposited ACF filters were characterized by using SEM, EDX and XRD analyses. To verify the effects of metal deposition on the adsorptive characteristics of ACF filters, the specific surface area and pore structure were determined by BET equation and BJH method, respectively. The antimicrobial activities of metal deposited ACF filters against E. coli, P. fluorescens, B. subtilis and M. luteus were characterized by modified Kirby-Bauer method. By SEM-EDX and XRD analyses, it was confirmed that the electroless plating method was adequate for deposition of Cu and Ag on the surface of ACF filters. BET and BJH analyses showed that the micropore volume of metal plated ACF filters decreased compared to the pristine ACF filter. The inhibition zones, which represent the antimicrobial effects, were formed around the Cu and Ag deposited ACF filters whereas not in the case of pristine ACF.
Authors: Mathieu Brochu, C.A. León, Robin A.L. Drew
Authors: Minoru Furukawa, Z. Horita, Terence G. Langdon
Abstract: This paper describes experiments in which high purity aluminum (Al) and copper (Cu) single crystals of different crystallographic orientations were processed for one pass by equal-channel angular pressing (ECAP). The deformed structures were examined using optical microscopy (OM), orientation imaging microscopy (OIM) and transmission electron microscopy (TEM). The results for Al single crystals are compared with those for Cu single crystals.
Authors: Jeong Il Youn, Young Jig Kim
Abstract: This paper presents semi-solid processing of Cu-Ag alloy to produce squirrel cage for small and medium induction motors. Complete die filling could be achieved with the slug at 1065 oC, casting pressure of 9 MPa and ram speed of 0.08 m/s. There were no defects in squirrel cage and slug temperature and ram speed affected the slot filling of rotor importantly, however, casting pressure rarely has an effect of the filling in this experiment. As the same thixoforming condition, when the ram speed was 1.5 m/s, slurry could not fill the slot and solidified like a needle shape. The rapid flow like this would be the cause of non-filling defect of slot because the slurry injected and solidified in the slot firstly was became the obstacle not to flow the rest of the slurry.
Authors: Andrey Molotnikov
Abstract: An analytical model describing the deformation behaviour of copper during the high-pressure torsion (HPT) processing is presented. The model was developed on the microstructural basis where the material is partitioned in two ‘phases’, the dislocation densities in cell walls and the dislocation densities cell interior, entering the model as scalar internal variables. The resulting ’phase mixture’ model is combined with strain gradient theory to account for strain non-uniformity inherent in SPD. It was demonstrated that gradient plasticity model is capable of describing the experimentally observed trends and accounting for a homogenisation of the accumulated shear strain across the HPT sample. The predictions of the model with respect to the ultrafine grain size produced by HPT and evolution of dislocation densities are in good agreement with experimental results reported by other research groups.
Authors: M. Ranjbar, M. Schaffie, Mohammad Pazouki, R. Ghazi, A. Akbary, S. Zanddevakili, S.A. Seied Baghery, Z. Manafi
Abstract: Several studies and different successful commercial applications had demonstrated that bioleaching can be an innovative approach that is capable to provide mining industry opportunities for essential growth in the medium term[2-18]. To identify the commercial application potential of bioleaching in Iranian copper industry, a research program was initiated. The objective of the main part of this program was to evaluate bacterial leaching processes for copper recovery from (i) high grade ores and flotation concentrates and (ii) low grade ores and flotation tailings. The latest results of these studies indicates the general operability of the bioleaching in both cases. At optimum conditions, the copper extraction from low grade materials was more than 80% and that from high grade ores and flotation concentrates about 95%, which should be high enough to justify the process economically.
Authors: C.T. Pan, P.J. Cheng, S.C. Shen, M.F. Chen, R.Y. Wang, Min Chie Chou, Tung Chuan Wu
Abstract: This study presents an innovative imprinting method to fabricate IC devices by micro-punch process. Normally, imprinting method is used to imprint plastic materials such as photoresist and polymeric materials. In this study, imprinting process is applied to micro-punch metallic materials directly for IC devices. Fabrications of IC devices with high aspect ratio structures ranging from micrometer to sub-micrometer are described. In this study, to keep the production costs as low as possible, a complete micro-punching process is applied to replicate IC devices. A combination of lithography, extra-hard alloy nickel cobalt (Ni/Co) electroplating process (as a metal imprint mold for punch) and chemical mechanic polishing (CMP) process is used to flat the extra-hard alloy micro-punch head. It is worth noticing that the Ni-Co electroplating process with hardness over Hardness of Vicker (Hv) 560 is developed. With such hardness, it can stand the high pressure and abrasivness to confine the accuracy during micro-punching process. With regard to the electroplating process, Ni-Co is deposited and covered on the photoresist template uniformly by electroplating. The Ni/Co mold is served as master for micro-punching process to replicate the pattern onto polyimide (PI) or copper sheets. Finally, the experimental results are measured and characterized.
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