Low temperature-rapid preparation of HfB2–SiC powders by microwave/molten salt assisted boro/carbothermal reduction

Jiangfeng HE, Yuan ZENG, Zhong HUANG, Jianghao LIU, Yunbo CAO, Gaoqian YUAN, Kezhuo LI, Quanli JIA, Haijun ZHANG, Shaowei ZHANG
2021 Journal of the Ceramic Society of Japan  
Phase pure HfB 2 SiC powders were efficiently synthesized via microwave/molten salt assisted boro/ carbothermal reduction (MMS-BCTR) method by using HfO 2 , SiO 2 , activated carbon and B 4 C powders as raw materials, and NaClKCl as a molten salt medium. The effects of mass ratio of salt to reactant (m s /m r ), holding period, reaction temperature and B 4 C content on the phase composition and microstructure of the synthesized HfB 2 SiC powders were investigated. The results showed that the
more » ... imal molar ratio of HfO 2 / SiO 2 /B 4 C/C was 3.0:1.0:3.2:4.0, m s /m r was 2.0, and reaction temperature and holding period were respectively 1250°C and 20 min. Rod-shaped HfB 2 and irregular SiC particles were uniformly distributed in the products, the former with a length of 0.5¯m and a diameter of 300 nm exhibited a single-crystal structure with a preferred growth along the [100] direction, while the latter had a particle size of about 300 nm.
doi:10.2109/jcersj2.21006 fatcat:bken3pc4gfg2hiqhs65zfry55q