Pressureless sintering, mechanical properties and oxidation behavior of ZrB2 ceramics doped with B4C.

A pressureless sintering process using different amounts of boron carbide (B 4 C) as sintering aid was investigated for the densification of zirconium diboride (ZrB 2 ). The sintering mechanism was converted from solid state sintering to liquid phase sintering as sintering temperature increased from 2150 to 2250 °C. B 4 C addition improved densification by removing the oxide impurities during solid state sintering. Besides, it could restrain the growth of ZrB 2 grains. At 2250 °C, ZrB 2 and B 4 C formed liquid phase which was well wetting ZrB 2 grains during liquid phase sintering process. The different roles of B 4 C on the microstructure development, mechanical properties and oxidation resistance of the sintered ZrB 2 -based ceramics were investigated. [ABSTRACT FROM AUTHOR]