锆刚玉莫来石-碳化硅复合材料的显微结构

采用OM、SEM、TEM及EDAX等手段研究了锆刚玉莫来石-碳化硅复合材料的显微结构。结果表明,ZrO_2及SiC均匀地分散于刚玉/莫来石构成的基质中。刚玉-刚玉(或莫来石)及莫来石-莫来石的晶间表面多数存在非晶质薄膜,但也有刚玉-莫来石两相直接结合的相界因扩散而形成固溶层。ZrO_2-刚玉(或莫来石)及SiC-刚玉(或莫来石)的相表面因相间扩散形成固溶层或扩散层而皆属直接结合。在刚玉和莫来石晶体里观察到有晶内ZrO_2存在,其形成原因可能是在烧结过程中,刚玉或莫来石晶体再结晶长大而包裹ZrO_2微粒所致。

THE MICROSTRUCTURE OF ZIRCONIA CORUNDUM MULLITE-SILICON CARBIDE COMPOSITES

The microstructure of zirconia/corundum/mullite-silicon carbide composites has been investigated by OM,SEM,TEM and EDXA.The results indicate that zirconia and silicon carbide particles are uniformly distributed in the corundum/mullite matrix.The grain boundary surfaces of corundum and/or mullite are mostly enveloped by glass films,but some solid solution layer between corundum and mullite is also observed indicating their direct bonding. On the phase boundaries of ZrO_2-corundum (or mullite) and SiC-corundum(or mullite), solid solution diffusion layers with concentration gradient are formed, indicating the nature of their direct bonding.Intragranular zirconia particles are observed inside some corundum and mullite grains; the zirconia particles may be entrapped by corundum(or mullite) during its process of recrystallization sintering accompanied by crystal growth.