화학공학소재연구정보센터
Journal of the Electrochemical Society, Vol.164, No.7, E144-E150, 2017
Electrochemical Synthesis of Nano-Metallic Carbides from the Mixtures of Metal Oxide and Graphite
Nanocrystalline transition metal carbides (TMCs, M = Ti, Zr, Hf, Nb and Ta) have been synthesized by direct electrochemical reduction of solid mixture precursors composed of transition metal oxides and graphite powder (TMOs-C) in molten CaCl2 at 850 degrees C. The synthesis temperature is much lower than that of the conventional carbothermic reduction process. SEM analysis showed that the particle sizes of the as-prepared TMCs powders were about 15-30 nm. The formation processes of nanocrystalline TMCs monitored by analyzing partially reduced samples were confirmed to be similar to each other and could be divided into three steps: TMOs-C first to CaMaOb and MCxOy, then to pure MCxOy and last to MC. It has been found that the electrolysis production of (TMCs)-Cs-V is much faster than that of (TMCs)-Cs-IV. The formation of intermediate MCxOy during the electrolysis processes was investigated and their stability should be the key influence factor of the electro-deoxidation rate of the mixtures. (C) 2017 The Electrochemical Society. All rights reserved.