氧化铝基纳米复合陶瓷显微结构的研究

MICROSTRUCTURE OF NANOCOMPOSITES WITH ALUMINA MATRIX

考察了Ａｌ２Ｏ３－ＳｉＣ和Ａｌ２Ｏ３－ＺｒＯ２（３Ｙ）－ＳｉＣ纳米复合陶瓷的断裂方式．由于ＳｉＣ的加入，材料以穿晶断裂为主．通过透射电镜观察，研究了纳米复合陶瓷中材料ＳｉＣ颗粒的分布，证明所制备的材料为晶内型纳米复合陶瓷．在Ａｌ２Ｏ３－ＺｒＯ２（３Ｙ）－ＳｉＣ纳米复合陶瓷中，小的ＺｒＯ２颗粒分布于Ａｌ２Ｏ３晶粒内，大的ＺｒＯ２晶粒位于Ａｌ２Ｏ３晶粒间，ＺｒＯ２的分布影响Ａｌ２Ｏ３晶粒的形状．通过高分辨透射电镜，观察了Ａｌ２Ｏ３－ＳｉＣ和Ａｌ２Ｏ３－ＺｒＯ２（３Ｙ）－ＳｉＣ纳米复合陶瓷中Ａｌ２Ｏ３／Ａｌ２Ｏ３，Ａｌ２Ｏ３／ＳｉＣ，Ａｌ２Ｏ３／ＺｒＯ２的界面．在两颗晶粒间的晶界几乎没有玻璃相的存在，证明纳米复合材料中晶界得到了加强，有利于力学性能的提高．

Fracture mode of Al 2O 3-SiC and Al 2O 3-ZrO 2(3Y)-SiC nanocomposites was studied by SEM. It is shown that the fracture mode is mainly of transgranular due to the addition of SiC. TEM observation reveals that nano_size SiC particles are uniformly located within matrix grains,which indicates that intragranular nanocomposites are obtained. In Al 2O 3-ZrO 2(3Y)-SiC nanocomposites, large ZrO 2 particles are distributed between Al 2O 3 grains, and small spherical ZrO 2 particles are distributed within Al 2O 3 grains. The addition of ZrO 2 influences the shape of Al 2O 3 grains. The interfaces of Al 2O 3/Al 2O 3, Al 2O 3/SiC and Al 2O 3/ZrO 2 in Al 2O 3-SiC and Al 2O 3-ZrO 2(3Y)-SiC nanocomposites were also studied by HREM,and no or little glass phase could be found on these interfaces. It is proved that the grain boundaries are strengthened beneficial to the improvement of mechanical properties of nanocomposites.