【摘要】 在热力学分析的基础上,以铁尾矿为主要原料,采用碳热还原氮化法合成了Si3N4粉.研究了合成温度和N2流量对反应过程的影响,利用X射线衍射法、扫描电镜等检测了产物的组成及显微结构.结果表明,随着合成温度的升高,产物中Si3N4相增多,1450℃时Si3N4相最多,且晶粒多呈等轴柱状或短棒状,此温度是最佳的合成温度.N2流量增加有利于还原氮化反应进行,600mL/min较适宜.合成过程中SiO气体的挥发导致试样质量损失较大.更多还原

【Abstract】 Based on thermodynamic analysis, Si3N4 powder was prepared by carbothermal reduction-nutridation from iron ore tailing. The phase composition and microstructure of sintered products were investigated by XRD and SEM techniques. The influences of synthesis temperature and N2 flow on the reaction process were also studied. The results show that Si3N4 phase in the products rises with increasing of synthesis temperature and reaches the maximum portion at 1450 ℃ , which is assumed to be the optimal synthesis temperature. And Si3N4 crystal mostly exists as equiaxedly columnar or shot rod-like β-Si3N4. The increase of N2 flow is favorable to the reduction-nutridation process, and the optimal flow rate of N2 is 600 mL/min. Volatilization of SiO results in obvious mass loss of the tested samples.更多还原