自增韧Si_3N_4陶瓷的制备与性能研究

STUDY ON THE PREPARATION AND PROPERTIES OF SELF-TOUGHENED Si_3N_4 CERAMICS

本文对自增韧Si3N4陶瓷材料进行了研究。采用SHS合成的α-Si3N4为原料,添加复合稀土氧化物Y2O3、Al2O3,采用热压烧结制备自增韧氮化硅,热压温度为:1800℃;压力为:30MPa。研究了不同的稀土、添加剂对氮化硅自增韧效果的影响。测试了样品体积密度、抗弯强度和断裂韧性。采用SEM和XRD分析了样品的显微结构和物相组成。实验结果表明,样品的最优配比为:70%α-Si3N4,22%TiC,6%Y2O3,2%Al2O3;样品的相对密度为99.82%,抗弯强度为788.04MPa;断裂韧性为12.45MPa.m1/2。其主晶相为β-Si3N4,有较明显的长柱状晶体。

The self-toughened Si3N4 ceramics were studied in this paper,by using α-Si3N4 as raw material,added mixed rare earth oxide Y2O3 and Al2O3.The effects of added differents rare earth oxide and additive on self-toughened Si3N4 ceramics were investigated by sintering in 1800℃,holding molding pressure in 30MPa.The density,bending strength and fracture toughness were tested.The microstructure and phase compositions were analysed by SEM and XRD.The experiment result showed that the optimal pereparation conditions were obtained on 70%α-Si3N4,22% TiC,6% Y2O3,2% Al2O3.The relative density,bending strength and fracture toughness of samples was respectively 99.82%,788.04 MPa and 12.45MPa.m1/2.β-Si3N4 were main phase in sample.There are more obvious elongated grains.