原位燃烧合成Si_3N_4/Ti(C,N)/SiC复相陶瓷热力学分析

THERMODYNAMIC ANALYSIS ON COMBUSTION SYNTHESIS OF Si 3N 4/Ti(C,N)/SiC IN SITU COMPOSITES

研究了用ＴｉＣ作添加剂时Ｓｉ粉坯在高压氮气中的燃烧行为．结果表明：ＴｉＣ加入量对燃烧合成产物的相组成有重要影响，原因在于ＴｉＣ加入量直接影响燃烧过程中氮气向反应前沿的渗透性，从而影响试样中不同部位氮气分压的变化．适当调整工艺参数，可以合成Ｓｉ３Ｎ４／Ｔｉ（Ｃ，Ｎ）／ＳｉＣ复相陶瓷，并从热力学角度对实验结果进行了合理的解释．

The combustion behavior of Si powder compacts with TiC as additive in pressurized nitrogen atmosphere was investigated.It is concluded that the amount of TiC added in the Si/Si 3N 4 powder compacts can significantly influence the phase composition of the combustion synthesized products.The variation of the nitrogen gas permeability of the specimen and therefore the variation of the local nitrogen partial pressure in different parts of the specimen during combustion process depend mainly on the TiC contents in the green compacts. In_situ combustion synthesis of Si 3N 4/Ti(C,N)/SiC composites was carried out through optimizing the processing parameters,besides,thermodynamic analysis result is in agreement with the experimental results.