关键词: 碳化硅, 耐火浇注料, 水蒸气, 抗氧化性, 耐压强度

Abstract:

Silicon carbide castables of different SiC contents (86% and 71%,by mass) were prepared using fused white corundum,silicon carbide particles and fines,activated alumina powder,silica powder and pure calcium aluminate cement as main starting materials,heat treating at 1 000 ℃ for 3 h,oxidizing in steam atmosphere at 1 000 ℃ for different durations (100,200,300,400 and 500 h).The mass and volume before and after oxidation,the bulk density,the apparent porosity and the cold compressive strength were tested.The phase composition and the microstructure before and after oxidation were analyzed by XRD and SEM.The results indicate that: (1)within 300 h of oxidation duration,silicon carbide shows an increasing oxidation rate;however,the oxidation rate is low during 300-500 h of oxidation duration;2)the oxidation rate of the specimen with 71% SiC is slightly higher than the one with 86% SiC;3)with the increasing oxidation degree of silicon carbide,the apparent porosity of the specimens tends to increase,followed by the declining bulk density and cold compressive strength.

Key words: Silicon carbide, refractory castables, steam, oxidation resistance, crushing strength