钠盐添加剂对制备碳化硅的影响

Effect of Na salt additives on preparation of silicon carbide

以石油焦和硅微粉为原料,在1 750℃下于感应炉中探究钠盐添加剂(NaCl,Na_(2)CO_(3))对制备碳化硅(SiC)的影响.首先研究原料硅微粉的成分,其次采用XRD,SEM及成分分析等表征手段具体研究不同添加剂对制备产物的物相组成、微观形貌及产量的影响.研究结果表明:硅微粉中主要杂质为CaO;添加质量分数为5%的NaCl,冶炼产物中SiC的质量分数高达90.4%,相较于不加添加剂组,冶炼产物中SiC的质量分数提高了4.8%,且晶粒生长较好,尺寸在2~5μm.采用FactSage软件对添加剂和硅微粉中金属杂质的反应进行模拟计算,结果表明,由于CaO和NaCl在本实验条件下发生了氯化反应,生成的气相逸出反应体系,从而提高了SiC的产率.

The effect of Na salt additives(NaCl,Na_(2)CO_(3)) on the preparation of silicon carbide was investigated at 1 750 ℃ with petroleum coke and silicon powder as raw materials in an induction furnace. Firstly, the composition of raw silicon powder was studied, and then the effects of different additives on the phase composition, microstructure and yield of the prepared products were discussed by XRD, SEM and composition analysis. The results showed that the main impurities in silicon powder was CaO, and the mass fraction of SiC was as high as 90.4% in the products with 5% NaCl, compared with the products without additives, the mass fraction of SiC increased by 4.8%. The particle size of SiC was 2~5 μm.FactSage software was used to simulate the reaction between the additives and the metal impurities in the silicon powder. The results showed that due to the chlorination reaction of CaO and NaCl, the gas phase escape from reaction system, which improved the yield of SiC.