Reaction Mechanism on Preperation of Ta With SOM Process

摘要

Tantalum metal was prepared by Solid Oxygen-ion Conducting Membrane(SOM) technology from Ta_2O_5 directly in molten CaCl_2. Through reaction mechanism of the metal-oxide-electrolyte three-phase interline (3PIs), the influence of pellets microstructure on the electrolysis process and products morphology were discussed. The results demonstrate that forming pressure, particle size and porosity of cathode pellets are significant factors for three-phase interline during electrolysis process. It was found that the big porosity and small particle can enhance the deoxidization rate, Contrarily, the compact out-layer of tantalum metal was formed. While the Ta_2O_5 pellet was pressed by 4MPa and sintered at 1150°C for 2 h has rational porosity and particle, the electrochemical reduction can be achieved via two steps: Ta_2O_5→Ta_2O_(5-x)→Ta.