摘 要: 采用自蔓燃高温合成方法 (SHS)合成氮化硅粉体, 借助于 XRD、SEM 等检测方法, 分析了自蔓燃高温合成氮化硅过程中氮气、 温度、稀释剂与孔隙率等工艺参数对合成产物的影响。结果表明: 只要 最高燃烧温度不高于相应氮气压力下 Si₃N₄ 的热分解温度, 就可以用 SHS 方法合成 Si₃N₄; 氮气压力下硅粉的自蔓燃合成反应, 必须要引入 Si₃N₄ 稀释剂来控制反应温度, 获得高 α相 Si₃N₄ 含量的粉体。压坯气 孔率控制在 30%～70%, 否则反应不能进行。SHS 法可以制备纯度很 高的氮化硅粉体。

关键词: 自蔓燃高温合成; 氮化硅; 工艺参数

Abstract: Si3N4 powder was prepared by the self-propagating high-tem perature synthesis (SHS) and X-ray diffraction and SEM were used to ex amine the Si3N4 powder. The following parameters were discussed: nitro gen purity and pressure, combustion temperature, diluents content and the porosity and so on. The experiment results showed that the SHS reac tion between Si powder and nitrogen would proceed at low nitrogen pres sure as long as combustion temperature no higher than the decomposition temperature of Si₃N₄. Under response nitrogen pressure Si₃N₄ would be obtained from silicon powder as starting raw materia1s in order to control reaction temperature and obtain high the content of αSi₃N₄ powder, the porosity of body was controlled at 30%～70% , otherwise, it was not able to react. The results indicate that the SHS method can prepare Si₃N₄ pow ders with high purity.

Keywords: self-propagating high-temperature synthesis;silicon nitride; processing parameter