预加SiC粉的碳热还原法制备SiC-B4C复合陶瓷粉

Preparation of SiC-B4C composite ceramic powder by carbothermal reduction method with pre-added SiC powder

为了改善制备SiC-B4C复合陶瓷的传统工艺流程(B4C与SiC机械混合后烧结),提高B4C与SiC在微观尺度上结合的均匀性和紧密性,使其更有利于烧结致密化,从而进一步提高复合陶瓷的综合性能,在碳热还原法制备B4C的配料中分别添加占总质量1%、2%、3%、4%、5%的SiC粉,干混均匀,再加入5%(w)的水搅拌均匀,然后采用油压千斤顶以20 MPa压力模压成型为?15 mm×10 mm的样坯,在80℃干燥10 h后,在1 800℃空气气氛中频感应炉中烧结50 min,最后进行XRD分析和SEM观察。结果表明:采用在碳热还原法制备B4C的配料中预加SiC粉的方法,成功制备了B4C分布均匀、SiC与B4C结合紧密的SiC-B4C复合陶瓷粉。随着SiC添加量的增多,B4C衍射峰强度明显增强,B4C晶粒形貌变得更加规则,且晶粒尺寸有所增大,表明SiC添加量增多促进了B4C的生成及其晶粒的生长。

This paper aimed to improve the traditional process flow of SiC-B4C based composite ceramics(B4C and SiC were mixed mechanically and then sintered),to improve the uniformity and tightness of the combination of B4C and SiC on the micro-scale,to make it more conducive to the sintering densification of ceramics,and to further improve the comprehensive properties of SiC-B4C ceramics.SiC powders(1%,2%,3%,4%,and 5%,by mass)were added into the ingredients of B4C prepared by carbothermal reduction method,dry mixing evenly,then adding 5%(by mass)water,then molding the green bodies to?15 mm×10 mm using an oil jack by 20 MPa pressure,after drying at 80℃for 10 h,firing in the air atmosphere at 1 800℃for 50 min in a medium frequency induction furnace.Then the specimens were analyzed by XRD and SEM.The results show that SiC-B4C composite ceramic powders with uniform B4C distribution and tight combination of SiC and B4C have been prepared by pre-adding SiC powder through carbothermal reduction method.With the increase of SiC addition,the diffraction peak intensity of B4C increases obviously,and the grain size of B4C becomes more regular,which indicates that the increase of SiC addition contributes to the formation of B4C and the growth of B4C grains.