以廉价的水玻璃和炭黑为原料, 采用沉淀-喷雾干燥法制备反应前驱体, 经碳热还原合成碳化硅. 由于原料间混合均匀, 前驱体在1500℃下加热5h后就能实现完全反应. 对产物用XRD、IR、BET及SEM等进行了表征, 并对反应过程中温度、时间的影响进行了研究. 结果表明, 前驱体在1500℃下反应5h制得的产物为平均晶粒尺寸在37nm左右的β-SiC, 比表面积为12.4m2/g. 碳热还原过程中, 适当升高温度、缩短反应时间有利于得到高质量的SiC产物.
Nanocrystalline SiC powder was synthesized by carbothermal reduction of the precursor of carbon black and silica gel prepared by precipitationspray drying slurry of carbon black and water glass. The carbothermal reduction of the precursors can be completed at 1500℃ for 5h because the method provides intimate contact between the reactants. The product was characterized by XRD, BET, SEM and TEM, the influence of temperature and time on the reaction was also studied. The results show that the powder synthesized at 1500℃ for 5h has characteristics of high quality with an average crystalline size of 37nm and specific surface area of 12.4m2/g. It reveales that during carbonthermal reation, appropreately rising temperature and shortening reaction time will be favorable to obtain the reation product of SiC with high quality.
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