Tabular corundum was used as the aggregates,and two kinds of cheap and highly reactive raw materials including clay and SiO2 powder were used as the SiO2 resources for synthesis mullite matrix,so that the mullite-corundum composite refractory was prepared by reactive sintering to reduce the cost of mullite sintering and to obtain ideal microstructures.For the sintered sample using clay as the SiO2-containing raw material,mullite synthesized amount is lower than the academic amount,but the mullite synthesized temperature is lower,and the mullite synthesized reaction is finished before 1550 ℃.The microstructure is more homogeneous with rod-shaped mullite grains.The sintering degree is better.For the sintered samples with SiO2 powder as the raw material of matrix,the amount of synthesized mullite is increased continuously with the increasing of sintering temperature and reaches to a complete mullitization at 1650 ℃.The granular mullite grains in the matrix tend to aggregate.The microstructure is dense but loose in local regions.The latter has higher strength but lower thermal shock resistance than the former.%以板状刚玉为骨料,莫来石为结合相,并以高岭土和无定型SiO2微粉作为合成莫来石的硅源,采用反应烧结工艺制备莫来石结合刚玉耐火材料,旨在降低莫来石的烧结成本及获得理想的显微结构.研究表明：以高岭土为硅源,莫来石生成量低于理论量,但生成温度较低,1550℃前已完成莫来石化反应,显微结构较均匀,烧结程度较好,莫来石呈长柱状;以SiO2微粉为硅源,莫来石量随温度提高连续增多,至1650℃接近理论生成量,莫来石呈粒状并倾向于偏聚,显微结构整体致密但局部疏松;后者强度,尤其高温强度显著高于前者,但抗热震性低于前者.
展开▼
