h-BN/Si_3N_4陶瓷复合材料的断裂行为及断裂韧性  

Fracture behavior and toughness of h-BN/Si_3N_4 ceramic composites

作　　者：魏大庆[1] 孟庆昌[1] 贾德昌[1] 

机构地区：[1]哈尔滨工业大学特种陶瓷研究所,黑龙江哈尔滨150001

出　　处：《材料科学与工艺》2007年第2期229-232,共4页Materials Science and Technology

摘　　要：以亚微米级α-Si3N4和h-BN粉末为原料,Y2O3-Al2O3为助烧剂,采用热压烧结制备了h-BN/Si3N4陶瓷复合材料.研究3h-BN含量对h-BN/Si3N4陶瓷复合材料断裂韧性及其断裂行为的影响.结果表明:随着h-BN含量增加,柱状β-Si3N4晶粒的直径和长径比均下降;未加h-BN时,β-Si3N4陶瓷以沿晶断裂为主,添加体积含量为6%和8%的h-BN后,复合材料出现明显的沿晶和穿晶断裂,而添加10%h-BN的陶瓷复合材料则以沿晶断裂为主.随着h-BN含量增加,h-BN/Si3N4陶瓷复合材料的断裂韧性下降,但由于h-BN颗粒对裂纹扩展的影响,因而其下降程度不大.h - BN/Si3N4 composites were fabricated by hot-pressing using sub - micrometer sized α-Si3N4, h - BN powders and Y2O3 - Al2O3 sintering additives. The effects of h - BN content on the fracture behavior and toughness of the h - BN/Si3 N4 ceramic composites were investigated. The results reveal that the diameter and aspect ratio of elongated β- Si3N4 grains in the composites decrease with increasing h - BN content. The dominant fracture behavior of the monolithic Si3N4 is intergranular fracture. After adding h -BN into Si3N4 ceramic, the intergranular and transgranular fracture are both significant in the composites containing 6% and 8% h-BN （volume fraction）. However, the dominant fracture behavior of the composites containing 6% h-BN is intergranular. The fracture toughness of the h -BN/Si3N4 ceramic composite decreases with increasing h - BN content ; however, the reduction extent is not pronounced due to the effect of the h - BN particles on the cracks propagation.

关 键 词：h-BN/Si3N4陶瓷复合材料 显微结构 β-Si3N4晶粒 断裂行为 断裂韧性 

分 类 号：TQ175.15[化学工程—硅酸盐工业]