Abstract: In order to improve the comprehensive service performance of Al₂O₃-SiC-C castables,microcrystalline Si₃N₄/Si₂N₂O multiphase powder synthesized by chemical combustion was used as an additive to prepare Al₂O₃-SiC-C castables,using brown corundum,tabular corundum,silicon carbide,active α-Al₂O₃ micropowder,SiO₂ micropowder,pure calcium aluminate cement,Si powder,and ball asphalt as raw materials.The effect of the multiphase powder extra-addition (0,1%,2%,3%,and 5%,by mass) on properties of the castables was studied;and the mechanism of Si₃N₄/Si₂N₂O to enhance the comprehensive properties of the samples was explored.The results show that:(1)Si₃N₄/Si₂N₂O multiphase powder can significantly improve the mechanical properties,oxidation resistance,and thermal shock resistance of the Al₂O₃-SiC-C castables;(2)the Si₃N₄/Si₂N₂O multiphase powder optimizes the microstructure of the castable and improves its overall performance by filling pores,promoting sintering reactions,and generating whisker like substances;(3)when the Si₃N₄/Si₂N₂O multiphase powder extra-addition is 3%,the castable has the optimal performance.

Key words: Si₃N₄/Si₂N₂O multiphase powder, Al₂O₃-SiC-C castable, oxidation resistance, thermal shock resistance

摘要： 为了提高Al₂O₃-SiC-C浇注料的综合服役性能,采用化学燃烧法合成的微晶氮化硅/氮氧化硅(Si₃N₄/Si₂N₂O)复相粉体为添加物,以棕刚玉、板状刚玉、碳化硅、活性α-Al₂O₃微粉、SiO₂微粉、纯铝酸钙水泥、单质Si粉和球沥青为原料,制备了Al₂O₃-SiC-C浇注料。研究了复相粉体外加量(外加质量分数分别为0、1%、2%、3%和5%)对浇注料性能的影响,同时探究Si₃N₄/Si₂N₂O增强试样综合性能的作用机制。结果表明:1)Si₃N₄/Si₂N₂O复相粉可以显著改善Al₂O₃-SiC-C浇注料的力学性能、抗氧化性能和抗热震性;2)Si₃N₄/Si₂N₂O 复相粉通过填充孔隙、促进烧结反应进行、生成晶须状物质等途径优化了浇注料的显微结构,提高了浇注料的综合性能;3)当Si₃N₄/Si₂N₂O复相粉外加量为3%(w)时,浇注料的性能最佳。

关键词: Si₃N₄/Si₂N₂O复相粉, Al₂O₃-SiC-C浇注料, 抗氧化性, 抗热震性