【摘要】 以TiSi2为反应原料,SiC作稀释剂,利用自蔓延高温合成(SHS)方法合成Si3N4-SiC-TiN复相陶瓷。计算了氮气压力对毛坯反应物理论转化率的影响,并在50、100和150 MPa三种氮气压力下进行了燃烧合成。结果表明,孔隙率为50 vol%的压坯在三种条件下反应都比较完全,反应物转化率随氮气压力增加而提高。而孔隙率为40 vol%的压坯在较低氮气压力下燃烧反应变得不完全,产物中残留大片Si。当压力为150 MPa时产物中未出现单质Si。说明氮气压力增大有利于氮气向反应前沿的渗入,进而提高反应物的转化率。更多还原

【Abstract】 The Si₃N₄-SiC-TiN multiphase ceramic was synthesized from TiSi₂ and SiC powders by self-propagating high-temperature synthesis in which SiC is acting as a diluent.The effect of nitrogen pressure on the conversion（degree） of the reactant was calculated in theory,and combustion synthesis was carried out under nitrogen pressures of 50,100 and 150 MPa,respectively.The results show that the green parts of 50vol% porosity are well nitrified under the three pressures,while those of 40vol% porosity can not be nitrified completely in which agglomerate Si is found when they were synthesized under lower pressure.However,there is no Si detected in the final products made by 40vol% porosity parts under 150 MPa nitrogen pressure.Accordingly,the high nitrogen pressure is of advantage to the infiltration of nitrogen and the increase of conversion degree.更多还原