还原气氛下Al_2O_3-SiC-Si_3N_4复相材料的反应烧结过程

Sintering Process of Al_2O_3-SiC-Si_3N_4 Composites at Reduction Atmosphere

以Si3N4,Al2O3,SiC及少量SiO2为原料,研究Al2O3-SiC-Si3N4复相材料在埋炭条件下的反应烧结过程,并借助SEM,EDX和XRD对其微观结构和物相变化进行了分析。研究结果表明,活性α-Al2O3和纳米SiO2能够促进Al2O3-SiC-Si3N4复相材料的烧结,体积密度提高,显气孔率降低,从而提高了强度。在复相材料的合成过程中,发现在高温下烧成的试样内有Sialon相和Si2N2O相生成。

Using Si_3N_4,Al_2O_3,SiC and SiO_2 as raw materials,the sintering process of Al_2O_3-SiC-Si_3N_4 composites is studied at reduction atmosphere and the microstructure and phase change of the composites are analyzed by means of SEM,EDX and XRD . The results show that active α-Al_2O_3 powder and nanometer-SiO_2 can promote the sintering property of Al_2O_3-Si-Si_3N_4 composites and a ceruain amount of Sialon phase and Si_2N_2O phase are produced under high temperature.It is also found that both α-Al_2O_3 powder and nanometer-SiO_2 can improve volume density and reduce the apparent porosity of the samples, thereby improving the strength of samples.