Direct electrosynthesis of Ti5Si3/TiC composites from their oxides/C precursors in molten calcium chloride

Ti5Si3/TiC composites have been electrosynthesized directly in molten CaCl2 electrolyte from pressed cathode pellets comprising powdered mixture of TiO2, SiO2 and C. This electrochemical experiment was carried out at 900 degrees C, 3.1 V and 1000 degrees C. 4.0 V using a graphite-based anode and an inert-oxygen-ion-conducting membrane-based anode, respectively. The membrane-based anode electrolysis system exhibits a higher current efficiency and reduction rate than the graphite-base anode electrolysis system. During the electro-deoxidation process, the oxide component was electro-deoxidized effectively and Ti5Si3/TiC powder was produced as the final product in the cathode. It is suggested that the reaction procedure involves compounding and electro-deoxidation processes simultaneously. Our work suggests that the solid-oxide oxygen-ion-conducting membrane-based anode electro-deoxidation process, so called the SOM process, is a promising low energy costs and environmentally friendly electrochemical method for the production of carbide-containing alloys, for instance, Ti5Si3/TiC composites. (C) 2012 Elsevier B.V. All rights reserved.