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.