Preparation of ZrC/Mo-Si metal silicides composite nano powder by direcrt electrochemical process in molten salt

ZrC/Mo-Si metal silicide composites are normally prepared by the sintering techniques at high temperature (1750~2100 ℃) or high pressure using ZrC and Mo-Si metal silicide powders as raw materials. However, these methods typically suffer from high cost, high energy consumption and high resource consumption. It is highly desired to develop a simple, low energy consuming and low-cost preparation method. In this work, ZrC/Mo-Si metal silicide composite nano-powder was prepared from a ZrSiO4/ MoO3/C mixture through a one-pot electrolytic process in molten salt. The effects of the preparation process of solid cathode, carbon content and type of carbon source on the electrochemical synthesis of ZrC/Mo-Si metal silicide composite nano-powder were investigated. The results show that ZrC/Mo-Si metal silicide composite nano-powder was prepared by electrochemical reduction at 800 ℃ under 3.1 V for 15 h in CaCl2-NaCl eutectic molten salt, and it was composed of nearly spherical particles with particle size less than 50 nm. It was found that the carbon powder with amorphous structure and relatively smaller particle size is more suitable as carbon source for electrochemical synthesis of ZrC/Mo-Si metal silicide composites. Moreover, the ratio of ZrC and metal silicide phases, as well as the composition of metal silicide in the final product can be controlled by adjusting the amount of carbon in the original material.