Abstract: To further improve their mechanical properties by utilizing the indirect sintering characteristics of boron oxide,Al₂O₃-SiC-C castables were prepared with mullite particles FM60,dense corundum,silicon carbide and α-Al₂O₃ micropowder as main raw materials and boron oxide (≤0.075 mm) as the sintering aid.The effect of the boron oxide fine powder addition (mass fractions of 0,0.2%,0.4% and 0.6%,respectively) on the structure and properties of the castables was investigated.The results show that adding boron oxide fine powder significantly increases the water demand of the castables,but it is beneficial for the formation of mullite whiskers,thereby strengthening the bonding between the aggregates and the matrix and significantly improving the mechanical properties of the samples.However,when the addition of boron oxide fine powder increases to 0.6%,the sample presents decreased length to diameter ratio of mullite whiskers and lower strength.Generally,the optimal boron oxide addition is 0.4%.

Key words: alumina-silicon carbide-carbon, castables, boron oxide, mullite whiskers

摘要： 为了利用氧化硼“间接烧结”特性,进一步提升Al₂O₃-SiC-C质浇注料的力学性能,以氧化硼(≤0.075 mm)为助烧剂,制备了以FM60莫来石颗粒、致密刚玉、碳化硅、α-Al₂O₃微粉等为主要原料的浇注料,探究了氧化硼细粉加入量(加入质量分数分别为0、0.2%、0.4%和0.6%)对Al₂O₃-SiC-C质浇注料结构与性能的影响。结果表明,添加氧化硼细粉会显著提升浇注料的加水量,但其有利于晶须状莫来石的生成,从而加强骨料和基质间的结合强度,试样的力学性能得到明显提升。但当氧化硼细粉加入量提高至0.6%(w)时,试样中莫来石晶须长径比减小,试样的强度降低。综合以上结果,氧化硼最佳加入量为0.4%(w)。

关键词: Al₂O₃-SiC-C质, 浇注料, 氧化硼, 莫来石晶须