ZHAO Fei 1, ZHANG Yuli 2, XU Qingshi 3
((1. School of Materials Science and Engineering, Jilin University of Chemical Technology, Jilin 132022, Jilin, China; 2. Grikin Advanced Materials Co. Ltd., Beijing General Research Institute for Nonferrous Metal, Beijing 102200, China; 3.AVIC Shenyang Aircraft Corporation, Shenyang 110034, Liaoning, China)
Abstract:In order to study its microstructure change and fracture morphologies in near sintering range, α-SiAlON ceramic was fabricated by cold isostatic pressing and pressureless sintering, using α-Si3N4, Al2O3 and AlN as matrix powders, and Y2O3 as a sintering aid. Its samples were characterized by XRD, SEM and EDS. The results show that: α-SiAlON phase can be formed by sintering domestic α-Si3N4 particles at 1800 ℃; short columnar grains are formed during the transition from powders to columnar crystals; the disorderly three-dimensional stacking of α-SiAlON columnar grains can improve the crack resistance of the matrix, thus enhancing the strength and toughness of α-SiAlON ceramic.
Key words:α-SiAlON; columnar grains; fracture; microstructure; pressureless sintering