摘要
通过透射电子显微分析和能谱分析，深入仔细地研究了烧结Ｓｉ３Ｎ４－ＭｇＯ－ＣｅＯ２陶瓷的微观结构及其性能的关系，发现当烧结温度为１８００℃时，ＭｇＯ在烧结过程中会自动析晶，烧结体的玻璃相只有铈硅酸盐而几乎没有ＭｇＯ，当烧结温度高于１８５０℃时，容易产生异常长大的二次Ｓｉ３Ｎ４晶粒，从而使烧结Ｓｉ３Ｎ４陶瓷材料的性能下降。并观察到了其中的亚晶粒、晶界及位错等微观结构。
The microstucture of the presureless sintered Si 3N 4 ceramics with MgO CeO 2 has been studied by TEM.The glassy phase is observed and confirmed directly by microdiffraction.EDAX analysis results show that the main function of the CeO 2 lies in the glass phase hardly containing any MgO.The cerium silicate glassy phase is good to wet Si 3N 4 and MgO CeO 2 is a most effective sintering aid for Si 3N 4. Excessive grain growth which is harmful to the mechanical properties occurs at above 1850℃.Microcracks and dislocations are observed in the excessive large grains.
