莫来石/SiC复相材料的烧结工艺和成分优化

Optimization of Sintering Process and Composition of the Mullite/SiC Composites

利用工业氧化铝和超细氧化硅合成莫来石 ,并结合SiC制备出了莫莱石 /SiC复相材料 .研究了烧结工艺及氧化铝和氧化硅的摩尔比对复相材料密度和强度的影响 ,并以材料的热震残余强度为指标、利用正交设计法研究了微量添加剂的影响效果 .结果表明 ,复相材料的体积密度随烧结温度的升高和烧结时间的延长均出现先升高后降低的规律 ,而开口气孔率的变化规律则相反 ;随结合相中Al2 O3 与SiO2 的摩尔比的提高 ,复相材料的密度增加、气孔率降低 ,而强度则先增后减 ;通过烧结工艺与结合相和添加剂成分的优化 ,材料密度最高可达 2 5g/cm3 ,抗折强度达 3 4 5MPa,耐压强度可达 90MPa,热震后的残余强度率为 67 2 % .

Mullite/SiC Composites were made using industrial alumna, SiO 2 and SiC. The effects of sintering process, mol ratio of Al 2O 3/ SiO 2 and trace additives on density, flexural strength, compressive strength and thermal shock resistance were studied. With the increasing of sintering temperature and sintering time, density increased first, and then decreased. With the increase of the mol ratio of Al 2O 3/ SiO 2, density increased, but strength increased first, and then decreased. Optimization of the sintering process, Al 2O 3/ SiO 2 mol ratio and trace additives produced a composite material with a density of 2 5 g/cm 3, a flexural strength of 34 5 MPa, a compression strength of 90 MPa, and a redundant strength ratio of 67 2% after thermal shock.