氧化锆对刚玉-莫来石复相材料显微结构的影响

Effects of Zirconia Additive on the Microstructure of Corundum-mullite Composites

通过扫描电镜、光学显微镜、X射线衍射仪和能谱探针研究了单斜晶型氧化锆对刚玉-莫来石复相材料显微结构的影响.结果表明:当氧化锆质量分数<25%时,氧化锆对刚玉-莫来石基体骨架有充实作用;氧化锆质量分数增加到35%左右时,基体骨架被氧化锆晶粒瓦解,处于一种过渡态;氧化锆质量分数超过40%后,氧化锆晶粒会堆集成串珠链状,并与基体主晶相共同交织成一种新的结构骨架,但新骨架仍较松散.氧化锆晶体的马氏体相变导致了刚玉-莫来石复相材料产生微裂纹,裂纹密度与氧化锆加入量有并增趋势.

The changes of microstructure of corundum-mullite system composites after adding zirconia were investigated and the grain-boundary compositions were analysed by means of SEM, OM, XRD, EDAX. The results showed zirconia additive could fill in the holes of corundum-mullite matrix and make the matrix densed after adding a few of zirconia. With zirconia addition content increasing, the corundum-mullite matrix suffered to break apart and zirconia grains began to link each other for aggregating, which weakened the binding between corundum grain and mullite grain, even produced the cracking. Meanwhile zirconia solution in the alumina and mullite grains were found.