摘要
本文采用Solgasmix-PV计算机程序计算了气相反应合成氮化硅超细粉的Si-N-H-Cl四元系的多相平衡。从理论上考察了温度、氮气、氢气、氨气流量对平衡时氮化硅摩尔数的影响。 本文还介绍了依据热力学分析,用高频N_2等离子体作为热源,NH_3、H_2、SiCl_4为反应气体合成Si_3N_4粉末的实验结果。高压电镜观察表明粉末粒度小于0.μm。化学分析测出的粉末组成为:N>37、O<3,C<0.1,Fe<0.01、Al<0.01、Ca<0.01、Mg<0.01(wt％)。粉末呈白色,非晶态。
The purpose of this paper is to find out the theoretical technological conditions of ultrafine Si_2N_4 powder formed in the vapor phase reaction of SiCl_4 with NH_3, H_2 and N_2 in a RF-plasma furnace. The thermodynamic equilibrium compositions of Si-N-H-Cl system have been calculated for different conditions using the SOLGASMIX-PV computer program. The effects of reaction temperature and the flow rate of N_2, H_2 and NH_3 on the equilibrium composition have been investigated theoretically.The conculsions of the present study can be summarized as follows:(1) Becasue of the decomposition of Si_2N_4, the synthesis must be carried out at a temperature Lower than 2000 K and preferably at 1700—1800K.(2) In order that SiCl_4 reacts completely with NH_3, the flow rate of NH_2 must be 3m^3/h at least, while the flow rate of SiCl_4 is 33.6g/min.(3) The change of the flow rate of H_2 slightly affects the equilibrium mole number of Si_2N_4.(4) If the flow rate of SiCl_4 remains constant, the increase of the flow rate of N_2 hardly affects the equilibrium mole number of Si_2N_4. So it is supposed that N_2 can not react with SiCl_4.(5) The gas which has influence on the equilibrium mole number of Si_2N_4 is mainly NH_2.Finally, some experimental results have been given in the paper.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
1989年第3期237-242,共6页
Journal of The Chinese Ceramic Society
关键词
氮化硅陶瓷
等离子体
气相
超细粉
RF-plasma
ultrafine powder
vapor phase reaction
thermodynamic analysis
