硅酸凝胶碳热还原氮化法制备氮化硅粉体的结构及形貌

Structure and Morphology of Si_3N_4 Powders Prepared by Carbon Thermal Reduction and Nitriding Method with Silicic Acid Gel

以水玻璃为硅源,炭黑为碳源,利用碳热还原氮化法制备了Si_3N_1粉体,研究了氮化温度、氮化时间和碳硅物质的量比对产物结构的影响,并对其形貌进行了观察。结果表明:氮化温度高于1 400℃时,产物全部为Si_3N_4;氮化时间大于5 h时,可以得到较纯的α-Si_3N_4;碳硅物质的量比为3:1时,产物全部为Si_3N_4;碳硅物质的量比为4:1的前躯体在1 400℃氮化5 h后得到的Si_3N_4粉体为不规则的、分散性良好的颗粒,颗粒尺寸为0.3～1μm;碳硅物质的量比为3:1的前躯体在1 450℃氮化5 h后得到的Si_3N_4粉体分散性良好,具有规则锤状形态。

Taking sodium silicate as silicon source and carbon black as carbon source, the Sia N, powders were prepared by carbon thermal reduction and nitriding method, and the effects of nitriding temperature, nitriding time and mole ratio of carbon to silicon on structure were studied, and the morphology was observed. The results show that all products were SiaN4 when nitriding temperature was over 1 400 ℃, the fairly pure α-SiaN4 could be obtained when nitriding time was more than 5 h, and all products were Si3N4 when the mole ratio of carbon to silicon was 3 ： 1. The Si3N4 powders prepared by nitriding the precursor with mole ratio of carbon to silicon of 4 ： 1 at 1 400 ℃for ,5 h had irregular particles and good dispersity, the particles size was 0. 3-1μm, and the Si3 N4 powders prepared by nitriding the prectlrsor with mole ratio of carbon to silicon of 3 ： 1 at 1 450 ℃ for 5 h had good dispersity and appeared regular hammer-like.