造粒粉体松装密度对氮化硅陶瓷球烧结致密化的影响

Effect of Apparent Density of Granules on Sintering Densification of Si_(3)N_(4) Ceramic Balls

以α-Si_(3)N_(4)粉为原料,Y_(2)O_(3),Al_(2)O_(3)为烧结助剂,通过控制喷雾干燥塔进口温度、喷片孔径制备不同松装密度的造粒粉体,采用气压烧结工艺制备Si_(3)N_(4)陶瓷球,研究造粒粉体松装密度对Si_(3)N_(4)陶瓷球烧结致密化的影响。结果表明:随造粒粉体松装密度的增大,Si_(3)N_(4)陶瓷球致密化程度先增大后减小;当松装密度为0.89 g/cm^(3)时,Si_(3)N_(4)陶瓷球显微气孔最少,致密化水平最好,致密化程度最高,力学性能最优,其抗弯强度为995 MPa,压碎载荷比为67%,断裂韧性为6.41 MPa·m^(1/2),维氏硬度为1505 HV_(10)。

Si_(3)N_(4) ceramic balls are prepared by gas pressure sintering process withα-Si_(3)N_(4) powder as raw material and Y_(2)O_(3) and Al_(2)O_(3) as sintering aids.The granules with different apparent densities are prepared by controlling the inlet temperature of spray drying tower and aperture of nozzle to research the effect of apparent density of granules on sintering densification of Si_(3)N_(4) ceramic balls.The results show that:the densification degree of Si_(3)N_(4) ceramic balls first increases and then decreases with increase of apparent density of granules;when the apparent density is 0.89 g/cm^(3),the Si_(3)N_(4) ceramic balls have the least micro pores,the best densification level,the highest densification degree and the optimal mechanical properties,the bending strength,crushing load ratio,fracture toughness and Vickers hardness is 995 MPa,67%,6.41 MPa·m^(1/2) and 1505 HV_(10) respectively.