Preparation of dense B 4 C ceramics via epoxy system gelcasting and different sintering methods

Abstract Gelcasting is proven effective for the mass production of large‐sized and complex‐shaped B 4 C ceramics. In this study, the uniform B 4 C green body with a relative density of 54.17% and compressive strength of 13.37 MPa was prepared by epoxy gelcasting. The nonlinear drying process of the epoxy system was investigated by real‐time monitoring, which guided the preparation route to prevent green bodies defects. Two sintering methods, spark plasma sintering (SPS) and pressureless sintering, were employed to densify the B 4 C green bodies. Due to the high quality of green body obtained by gelcasting, B 4 C ceramics with a dense and fine‐grained microstructure were successfully prepared via SPS at 1700°C. When the B 4 C ceramics was pressureless sintered alone at 2250°C, their densification were failed and instead caused abnormal grain growth. By incorporating TiB 2 , the pressureless sintering of B 4 C at 2100°C basically achieved densification, reaching a relative density of 95.04%. The gelcasting process enabled uniform distribution of TiB 2 grains in the B 4 C matrix, which not only inhibited grains growth, but also promoted the sintering ability of B 4 C ceramics. These results provide valuable insights into the epoxy gelation of B 4 C ceramics, showing potential for large‐scale production of complex‐shaped B 4 C ceramics at relatively low sintering temperatures.