热压添加复合助剂的Si_3N_4陶瓷的显微结构与力学性能

Microstructure and Mechanical Properties of Hot-Pressed Si_3N_4 Ceramics with Compound Additives

本工作对两种成分的Si_3N_4陶瓷进行了热压烧结。测定了密度、硬度、抗弯强度、断裂韧性等性能指标。在扫描电镜下进行了显微结构及断口观察。研究表明,同时加入几种添加剂(Y_2O_3、MgO、AIN、Al_2O_3等)对形成均匀致密、长径比大,粒径小的柱状β-Si_3N_4有利,高的断裂韧性和抗弯强度的获得主要取决于以柱状β晶为基本特征的显微结构。

Two kinds of Si3N4 ceramics were sintered by hot-pressing. Their density, hardness, flexural strength and fracture toughness were measured. Microstructure and fracture surface were observed with scanning electron microscope. The restlts showed that the mixture of several additives (Y2O3, MgO, AIM, Al2O3, etc) helped to form compact columnar β-Si3N4 grains. These columnar β grains have high aspect ratio and fine particle size. According to the study, high fracture toughness and flexural strength were mainly contributed by the microstructure of the material.