Keiichi Kobayashi, Yuichi Oka and Ryosuke O. Suzuki
Department of Materials Science, Graduate School of Engineering, Hokkaido University, Hokkaido 060-8628
TiO2 was successfully reduced at 1223 K by calcium, which was deposited due to the molten salt electrolysis of CaO dissolved in CaCl2. Changing the area of electrodes and the electrodes distances, the current density and the Ca concentration near the cathode were varied, respectively. At the initial stage of reduction, metallic Ti powder with the lower oxygen concentration was obtained at the lower current density, where most of electrochemically deposited Ca was efficiently used for the reduction. Meanwhile, at the final stage of reduction/deoxidation, Ti powder with the much lower oxygen concentration were obtained at the higher current density, where the higher Ca concentration was available near the cathode. On order to obtain the metallic powder with the low oxygen content, the formed Ca can penetrate even into the inner part of the sintered oxide.
titanium oxide, reduction, current density, molten salt, calcium chloride
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