Abstract:
ZrB
2-SiC composite powder was prepared by microwave and molten-salt co-assisted boro/carbothermal reduction method with ZrO
2, SiO
2, B
4C and activated carbon as reactants, and with NaCl and KCl as molten-salt. The effects of reaction temperature, reaction time, B
4C and molten-salt content on the phase composition and microstructure of the product were investigated. The results show that with the increase of reaction temperature, reaction time, B
4C content and molten-salt content, the synthetic reaction of ZrB
2 and SiC occurred more completely, and the diffraction peaks of ZrB
2 in the product were getting stronger. When the reaction temperature was 1 200℃, reaction time was 20 min, salt to reactant mass ratio was 2:1 and the molar ratio of B
4C to ZrO
2 was 0.8, the pure-phased ZrB
2-SiC composite powder with average grain size of 38 μm was obtained, where ZrB
2 had a one-dimensional rod-like structure with a diameter of about 1.35 μm and an average length to diameter ratio over 10.