Materials Transactions Online

Materials Transactions, Vol.50 No.12 (2009) pp.2704-2708
© 2009 The Japan Institute of Metals

Influence of Current Density on the Reduction of TiO2 in Molten Salt (CaCl2 + CaO)

Keiichi Kobayashi, Yuichi Oka and Ryosuke O. Suzuki

Department of Materials Science, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Japan

Titanium dioxide (TiO2) was successfully reduced at 1223 K by calcium, which was deposited due to the molten salt electrolysis of CaO dissolved in CaCl2. The current density and the Ca concentration near the cathode were changed by varying the electrodes' surface areas and the distances between an anode and cathode, respectively. At the initial stage of reduction, metallic Ti powder with a lower oxygen concentration was obtained at a lower current density; in this case, most of the electrochemically deposited Ca was efficiently used for reduction. Meanwhile, at the final stage of deoxidation, Ti powder with a much lower oxygen concentration was obtained at a higher current density. In order to obtain metallic powder with a low oxygen concentration, the formed Ca should penetrate the inner part of the sintered sample.

(Received 2009/6/2; Accepted 2009/8/31; Published 2009/10/21)

Keywords: titanium oxide, reduction, current density, molten salt, calcium chloride

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