助烧体系对注射成形碳化硼陶瓷烧结性能的影响

采用粉末注射成形技术制备碳化硼陶瓷微结构零件,用SiC-Al2O3-Y2O3和SiC-ZrO2两种助烧体系进行烧结。分析助烧体系(SiC-Al2O3-Y2O3和SiC-ZrO2)对零件的致密度、相组成、微观组织和断裂机制的影响。结果表明:添加助烧剂可有效提高碳化硼制品的烧结性能。采用SiC-Al2O3-Y2O3助烧体系烧结的零件由B4C、SiC、B2YC2和YAG等4种相组成,随烧结温度升高,其致密度先增加后减小,在1 950℃烧结时达到最大值,为97.1%。而采用SiC-ZrO2助烧体系时致密度随烧结温度升高而增加,在2 240℃达到最大值,为95.1%,相组成为B4C、SiC和ZrB2相。零件的断裂形式都以穿晶断裂为主,含有一定的沿晶断裂。

Effect of additive systems on sintering properties of injection molded boron carbide

Boron carbide micro-structured products were fabricated by powder injection molding process combining with promotive system.The effects of promotive systems(SiC-Al2O3-Y2O3 and SiC-ZrO2) on the relative densities,phase compositions,microstructures and fracture mode of samples were investigated.The results show that sintering properties of boron carbide parts can be improved greatly by using promotive systems.Sintered samples with SiC-Al2O3-Y2O3 promotive system consists of B4C,SiC,B2YC2and YAG phase and the relative density of samples begins to increase and then decrease with increasing sintering temperature,the maximum value is acquired at 1 950 ℃,which is 97.1%.The density of samples with SiC-ZrO2 promotive system consistently increases with increasing sintering temperature,the maximum value of 95.1% is obtained after sintering at 2 240 ℃,and the phase compositions of sintered samples are B4C,SiC and ZrB2.The main facture mode of both sintered samples is transgranular fracture,including partly intergranular fracture.