Effect of Al_2O_3/Y_2O_3 on properties of B_4C ceramics prepared by pressureless sintering
SHI Xiumei;CUI Hong;CAO Jianwu;LI Zhipeng;ZHANG Cong;TANG Weihong;XING Wenfang;WANG Zhiqiang;Northwestern Polytechnical University;Ningbo Branch of Chinese Academy of Ordnance Science;
Boron carbide(B4C) ceramics were manufactured by pressureless sintering method under 2 250 ℃ sintering temperature,and with the macro B4 C powder as the main raw material,polyvinyl alcohol(PVA)and phenol resin as binding agent and Al_2O_3+Y_2O_3as composite sintering aids. The effect of different amount of Al_2O_3+Y_2O_3aids on the microstructure,sintering properties and mechanical properties of B4 C ceramics was investigated. The results indicate that when the content of Al_2O_3+Y_2O_3aids reaches 0.75%(mass fraction),the best properties of B4 C ceramics are achieved by pressureless sintering method. The relative sintering density,bending strength and hardness are 96.4%,360 MPa and 26.47 GPa,respectively. The microstructures of B4 C samples show that the pores are very small and homogeneously distributed across the surface.