论文部分内容阅读
利用高压气—固燃烧合成法，以ＴｉＳｉ２和ＳｉＣ为原料制备了Ｓｉ３Ｎ４－ＴｉＮ－ＳｉＣ复相陶瓷。实验中发现反应过程中出现的液相降低了产物的转化率；分析了稀释剂对产物的转化率与燃烧温度的影响及氮气压力在燃烧中的作用；解决了液相、稀释剂和燃烧温度之间的矛盾，即通过提高氮气压力来完成。研究发现产物孔隙率降低的原因为：ＴｉＳｉ２分解后的体积膨胀，Ｓｉ氮化成Ｓｉ３Ｎ４后发生的体积膨胀和高温时产物受到的等静压作用。分析了ＴｉＳｉ２的氮化机制，即ＴｉＳｉ２与氮气反应首先生成ＴｉＮ和Ｓｉ，然后Ｓｉ再与氮气合成Ｓｉ３Ｎ４。
Si3N4-TiN-SiC composite ceramics were prepared from TiSi2 and SiC by high-pressure gas-solid combustion synthesis. It was found that the liquid phase in the reaction decreased the conversion of the product. The effect of the diluent on the conversion of the product to the combustion temperature and the effect of the nitrogen pressure on the combustion were analyzed. The liquid phase, diluent and combustion temperature The contradiction between, that is, by increasing the pressure of nitrogen to complete. It is found that the reason for the decrease of the product porosity is the volume expansion after the decomposition of TiSi2, the volume expansion after Si nitriding into Si3N4, and the isostatics under high temperature. The mechanism of nitriding of TiSi2 was analyzed, that is, TiN2 was first reacted with nitrogen to form TiN and Si, and Si then synthesized Si3N4 with nitrogen.