烧成条件对Al2O3-C材料微结构与性能的影响

Effect of Firing on Physical Properties and Microstructure of Al_2O_3-C Refractory

研究了不同的烧成温度及保温时间对Al_2O_3-C材料物理性能的影响,采用压汞仪和扫描电镜分析了其微观结构以及相组成的变化规律。结果表明,在实验温度范围内,低温烧成或低温条件下适当延长保温时间,有利于材料中SiC晶须的生成和生长发育,因此材料的显气孔率、体积密度、冷态耐压强度、热态抗折强度较高温条件下烧成的优越;提高烧成温度,SiC晶须发生继续氧化,导致SiC晶须数量减少,质量变差,并且硅-碳-氧反应可能更倾向于形成硅氧化物以及气体,这些气体物质逸出使材料的气孔增多,显气孔率增大,但同时也使材料中d<1μm的微气孔率增加。

The effect of sintering temperature and holding time on the physical properties of the Al2O3-C material was studied. Microstructure and phase composition of the fired materials were analyzed by SEM andmercury pressed-in instrument. A lower temperature or a longer sintering time generated SiC whiskers that improved the bulk density, CCS and HMOS of the materials. A higher firing temperature was not good for the SiC whisker growth, and the Si-C-O system was liable to be oxidized that produced pores in the materials.