碳热/硼热还原法制备ZrB2-SiC复合粉体

摘要

ZrB2-SiC composite powders were synthesized by the boro/carbothermal reduction method using ZrO2,SiO2,B2O3 and activated carbon as raw materials.The thermodynamic analysis was conducted on the formation process.The effects of synthesis temperature and activated carbon content on the phase composition and micromorphology of ZrB2-SiC composite powders were investigated.The results show that ZrB2-SiC composite powder can be synthesized at temperatures of 1 400-1 450 ℃.Increasing the reaction temperature was beneficial to the synthesis of ZrB2-SiC composite powder and the relatively pure ZrB2-SiC composite powder was obtained by the reaction at 1 450 ℃ for 3 h.Meanwhile,the phase composition of the obtained ZrB2-SiC composite powders was basically similiar with the activated carbon of excessive mole fraction of 50％ and 75％.%以氧化锆、氧化硅、氧化硼及活性炭为原料,采用碳热/硼热还原法制备了ZrB2-SiC复合粉体,并对合成过程进行了热力学分析,研究了反应温度以及活性炭含量对复合粉体物相组成和显微结构的影响.结果表明:在1 400～1 450℃温度范围可以合成ZrB2-SiC复合粉体;提高反应温度有利于合成ZrB2-SiC复合粉体,经1 450℃保温3h反应可以得到较纯的ZrB2-SiC复合粉体;活性炭过量50％和75％(物质的量分数)条件下制备的复合粉体的物相组成基本相同.