冲击波活化热压烧结氮化硅粉末  

Shock Activation and Hot-Press Sintering of Si_3N_4 Powder

作　　者：刘静宇[1] 蔡清裕[2] 张术华[3] 

机构地区：[1]长沙大学理化系,湖南长沙410003 [2]国防科技大学理学院,湖南长沙410073 [3]国防科技大学航天与材料工程学院,湖南长沙410073

出　　处：《国防科技大学学报》2000年第3期65-69,共5页Journal of National University of Defense Technology

摘　　要：对Si3 N4粉末实现了三种不同压力的冲击波预先处理 ,而后采用三种不同的热压烧结条件制得Si3 N4陶瓷。运用SEM ,TEM ,HRTEM和XRD等手段分析了粉末和陶瓷的结构特性 ,同时测试了材料的性能。结果表明 :冲击波压力没有导致Si3 N4粉末的相变 ,TEM观察表明Si3 N4晶粒中有大量的位错及位错群 ,冲击波的作用主要是通过引入大量位错和其他缺陷促进致密化过程 ,提高陶瓷材料的机械性能。经过40GPa冲击波活化 1 80 0℃热压烧结的Si3 N4陶瓷性能最好 ,弯曲强度达 1 1 0 7.2MPa ,断裂韧性达 1 2 .2 0MPa .m1/2 。Si 3N 4 powders have been pre treated by shock activating and hot pressed into Si 3N 4 ceramics. Three kinds of shock pressure, and three different sintering temperatures are used in the experiments, SEM, TEM and X ray Diffraction have been used to analysis the structure of the Si 3N 4 powders and ceramics. The properties of Si 3N 4 ceramic have been tested. The results show that shock activation give positive action to the densification of Si 3N 4 powder and the increase of properties of the Si 3N 4 ceramics; the ceramic parts shocked under 40 GPa and sintered under 1800℃ have the best properties. The bend strength reaches 1107.2 MPa, at the same time, the fracture toughness reaches 12.20 MPa.m 1/2 .

关 键 词：冲击波活化 烧结 氮化硅粉末 

分 类 号：TF124[冶金工程—粉末冶金]