Structure and Mechanical Properties of Densified Boron Carbide Ceramics by SPS
Wang Ling,Chen Daming,Zhang Hu,Tong Jianfeng (Beijing Institute of Aeronautical Materials,Beijing 100095,China)
Densified boron carbide ceramics were synthesized by a spark plasma sintering(SPS) process using boron-rich boron carbide powders as the raw material. The influence of SPS experimental parameters on the structure and mechanical properties of boron carbide ceramics was investigated. It showed that boron carbide having a densification of 99.7% was obtained by SPS at a relatively low temperature for a short dwell time. Sintering temperature and time affected the densification and the grain size of boron carbides. Amorphous phase formed on the grain surface during sintering,which would lead to a transition of the fracture type of boron carbides from transgranular to intergranular. As a result,amorphous phase helped an increase in fracture strength and fracture toughness. Boron carbide ceramics synthesized by SPS exhibited excellent mechanical properties,i.e.,densification was 99.6%,bending strength was 550.1 MPa,and Vickers hardness was up to 39.52 GPa,respectively.