原位生长片状晶增韧氧化铝陶瓷的制备与显微结构

Preparation and Microstructure of In-situ Platelet Grain Growth to Toughen Alumina Ceramics

α-A l2O3中加入复合添加剂,在1 500℃,2 h条件下无压烧结,制备出原位生长片状晶增韧的氧化铝陶瓷。烧结行为和显微结构研究表明:在1 500℃下烧结时,获得板片状晶粒。加入CaF2和S iO2复合添加剂时,生长的晶粒呈现片状,大小均匀,断裂韧性达到4.3 MPa.m1/2;加入CaF2和高岭土复合添加剂时,由片状晶粒形成A l2O3陶瓷基体中,弥散分布着粗大的板块状晶粒,有效的提高了A l2O3陶瓷的致密度,相对密度达到96.8 g/cm3。

The platelet grain alumina ceramics were fabricated by adding small amount of composite additives into fine alpha alumina powder and sintering at 1 500 ℃ for 2 h pressurelessly. The sintering behavior and microstructure development were studied. The re- suits show that the platelet grains can be formed equably by adding CaF2 and SiO2. The fracture toughness of the samples reach to 4.3 MPa · m^1/2. Adding CaF2 and kaolinite into alumina ceramics can also form platelet grain, but a few bulky platelike grains disperse in matrix, so the relative densities of the samples reach to 96.8 %.