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Abstract: A Nb–Ti–Ni hydrogen permeable alloy was synthesized as a powder using the OS process, which involves the simultaneous reduction of a mixture of Nb, Ti, and Ni oxides by Ca that is generated from molten CaCl2 via electrolysis. The mechanism confirmed that a BCC-(Nb, Ti) phase easily formed at an early stage of the reaction followed by the generation of a B2-TiNi phase from the lower oxides such as NbO and Ti2O. The oxygen content of the synthesized alloy decreased significantly to 0.27mass% with increased electric charge. The three elements were uniformly distributed at the macroscopic level. [Copyright &y& Elsevier]

Abstract: The electrochemical decomposition of CO2 gas in LiCl–Li2O or CaCl2–CaO molten salt was studied to produce carbon. This process consists of the electrochemical reduction of the oxide, Li2O or CaO, and the thermal reduction of CO2 gas by metallic Li or Ca. Two kinds of ZrO2 solid electrolytes were tested as an oxygen ions conductor and removed oxygen ions from the molten salts to the outside of reactor. After the electrolysis in the both salts, the aggregations of nanometer-scale amorphous carbon and rod-like graphite crystals were observed by transmission electron microscope. When 9.7% CO2–Ar mixed gas was blown into LiCl–Li2O or CaCl2–CaO molten salt, the current efficiency was evaluated to be 89.7% or 78.5%, respectively, by the exhaust gas analysis and the supplied charge. When the solid electrolyte with the better ionic conductivity was used, the current and the carbon production became larger. The rate determining step of this proposal was diffusion of oxygen ions in ZrO2 solid electrolyte. [Copyright &y& Elsevier]

Abstract: Metallic nickel powders with low and uniform residual oxygen content were produced from NiO using the molten salt electrolysis of CaO in CaCl2 melt. Suitable amount of CaO for the reduction was in the range of 0.5–3.0mol% CaO. The electrical isolation of NiO from both electrodes could produce metallic Ni in CaCl2 melt. Separating the metal oxides from the cathode confirmed the mechanism of calciothermic reduction that the electrolysis of dissolved CaO in CaCl2 melt produces Ca, and that the dissolved Ca in molten CaCl2 successfully reduces NiO to metallic Ni. An average of about 600ppm oxygen in Ni sample was achieved directly from oxide, when NiO was detached from the cathode. [Copyright &y& Elsevier]

Abstract: Repassivation kinetics of titanium were investigated in artificial saliva by the photon rupture method, PRM, combined with anodizing. PRM uses focused pulsed Nd–YAG laser beam irradiation to remove oxide film and metal. The effects of the applied potential and F− ions on the repassivation kinetics of titanium were examined electrochemically. All conditions in this study use specimens that were repassivated within about 100ms after the laser beam irradiation. The current transients after the laser beam irradiation showed a rapid increase, followed by a decrease with a slope of the log i vs. log t plots of about −1.5. The measured slope is steeper than what would be expected with the high field oxide film formation theory. This result suggests that the oxidation of titanium takes place through a combination of electrochemical and chemical reactions. More NaF results in a higher peak current density and amount of charge after laser beam irradiation. The influence of F− ions on the repassivation kinetics may be explained by localized pH changes caused by dissolution of titanium immediately after the laser beam irradiation. [ABSTRACT FROM AUTHOR]