高温流态化合成氮化硅的实验研究

Experimental Study on Preparation of Silicon Nitride by High-temperature Fluidization

采用自行设计的高温流化床，利用流态化技术合成了氮化硅粉。研究了温度对硅粉床层流化特性的影响。利用K值法对XRD结果进行计算分析，得到了转化率随反应时间的变化规律。结果表明：随着温度的升高，床层流化所需的最小气速增大。氮化反应初期存在一定的反应诱导期，在转化率为20％～40％时，反应比较剧烈。随后反应速度减缓，160min后反应速度基本不再变化。流态化技术的采用为实现常压条件下连续化生成氮化硅工艺提供了实验基础。

Silicon nitride was synthesized by high-temperature fluidization using self-designed fluidized bed. The effect of temperature for silicon fluidization was studied. The conversion with different reaction time was obtained by K value method. The result indicated that the minimal velocity of fluidization ascended with increased temperature. The induction period existed in the initial stage. The reaction was rapid with the conversion rate between 20% and 40%. Then, the reaction rate decreased and keep invariable after 160min. The utilization of fluidization provided experiment foundation for the consecutive preparation of silicon nitride.