Pressure-induced preferential grain growth, texture development and anisotropic properties of hot pressed hexagonal boron nitride ceramics

Textured hexagonal boron nitride ceramics were prepared by hot pressing, using boron nitride powders as starting materials. The results showed that a high sintering temperature and moderate external pressure helped to form a textured microstructure when using boron nitride powder with a low degree of order and a broad particle size distribution. The flake-like boron nitride grains tended to orient along the hot pressing direction via pressure-induced preferential grain growth. The obtained textured boron nitride ceramics demonstrated strong anisotropic mechanical and thermal properties.