摘 要：采用自蔓燃高温合成方法合成 β- 氮化硅粉体，分析了合成氮 化硅过程中氮气、温度、稀释剂与孔隙率等方面的影响。 采用 XRD 研 究相的组成，用 SEM 观察粉末的显微结构。 研究结果表明：自蔓燃合 成方法制备的氮化硅陶瓷粉体，β 相含量由块状产物中心向表层减 少，得到的 β-氮化硅晶体结构完整，表面光滑无缺陷，考虑到燃烧温 度（Tcom），在氮化硅粉体的合成过程中，涉及到 3 个反应机制：低温机 制、中温机制、高温机制。 NH₄Cl 在反应中分解，为反应提供了 NH₃，并 与硅粉反应；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和反应速度，获得不同相含量的粉体；压坯气孔 率控制在 30%～70％，否则反应不能进行。 

关键词：自蔓燃高温合成；氮化硅；反应机制

Abstract:β-Si₃N₄ powder was prepared by the self-propagating high-tem perature synthesis (SHS) and examined by X-ray diffraction and SEM. It was studied how the following parameters influenced the final product: nitrogen purity and pressure， combustion temperature， diluents content， the porosity， and so on. The experimental results showed that the differ ent type of β -Si₃N₄ powder with integrated crystalloid structure and smooth surface could be prepared by SHS as long as the parameters be controlled during the reaction，β phase content decreased from the center of the cake to the surface. Because of the existence of the NH₄Cl， the re action involved not only the silicon nitriding mechanism，but also other mechanisms. Considering the combustion temperature，the SHS Si₃N₄process involves three mechanisms: low-temperature mechanism， mod erate-temperature mechanism， high-temperature mechanism. During the process Si₃N₄ powder could be introduced as starting raw materia1 in or der to control reaction temperature and obtain the desired α content of Si₃N₄ powder， the porosity of body should be controlled at 30%～70%otherwise， SHS reaction would not carry on. The Si₃N₄ powder with high α content could be prepared when fine silicon metal powder used. 

Keywords： self-propagating high-temperature synthesis；silicon ni tride；reaction mechanism