叠氮化钠联合卤化铵燃烧合成氮化硅粉体

采用叠氮化钠作为固态氮化剂,同时以卤化铵作为活性稀释剂,通过对燃烧温度特征曲线和燃烧产物相组成的分析,研究了两者的协同作用对于燃烧合成氮化硅粉体的影响.研究结果表明:叠氮化钠和卤化铵的热分解可增加硅粉内部孔隙率和氮气渗透性,也能为Si-N反应提供内部氮源.叠氮化钠和卤化铵均可作为Si-N反应的催化剂,可促进硅粉向氮化硅的氮化转变.叠氮化钠联合卤化铵的使用能够有效地降低燃烧温度,使燃烧反应以低温模式进行,有利于α-Si₃N₄的生成.随着反应物中叠氮化钠含量的增多,燃烧产物中α相氮化硅含量也相应地有所提高.

Combustion synthesis of Si3N4 powder using sodium azide and ammonium halide as additives

The effects of sodium azide used as solid nitrogen source and ammonium halide used as active diluent on the combustion synthesis of Si₃N₄ powder were investigated through analyzing the combustion temperature profiles and the phase composition of the combustion products, The research results show that the endothermic decomposition of these two kinds of additives can increase the porosity of the reactants and thus improve the nitrogen permeability. The additives can also provide interior nitrogen source and act as catalysts of Si-N reaction that facilitates the combustion reaction of silicon in nitrogen atmosphere, The addition of sodium azide and ammonium halide can effectively lower the combustion temperature and maintain the combustion reaction at a relatively low temperature which is in favor of the formation of α-Si₃N₄. Appropriate addition of sodium azide and ammonium halide can promote the nitridation of silicon and increase the α-content in the combustion products.