氮化硅陶瓷的增韧研究

研究了加入ZrO_2和SiC晶须对热压烧结Si_3N_4的增强增韧作用。加入ZrO_2和SiC晶须能提高复合材料的断裂韧性K_(IC),但降低了抗弯强度。分别加入10vol％纯ZrO_2和含有钇的Y-ZrO_2,使Si_3N_4陶瓷的室温K_(IC)从原来的6.3MPa·m~(1/2)分别提高到7.3MPa·m~(1/2)和7.6MPa·m~(1/2)。加入10wt％SiC晶须,使Si_3N_4陶瓷的室温K_(IC)从6.3MPa·m~(1/2)提高到7.1MPa·m~(1/2)。

STUDY ON TOUGHENING OF Si_3N_4 CERAMICS

In this paper the influences of ZrO, and SiC Whiskers on strengthening and toughening effects of HP Si3N4 have been studied. By addition of ZrO2 and SiC whiskers, fracture toughness K IC, of composites increased, but flexural strength decreased simultaneously. In separate addition of 10vol% pure ZrO, and Y ZrO2 containing Y, fracture toughness of the Si3N4 ceramics at room temperature increased from 6.3 to 7.3 and 6.3 to 7.6 MPa m respectively. The improvement of fracture tonghness is due to the toughening effect of microcrack. By the way of addition of 10wt% SiC whiskers, at room temperature KIC of Si3N4 ceramics is increased from 6.3 to 7.1 MPa m . Toughening of SiC whisker was caused by crack deviation and pull-out effect of whiskers as well.