Anisotropies in structure and properties of hot-press sintered h-BN-MAS composite ceramics: Effects of raw h-BN particle size

Abstract

Effects of raw h-BN particle size from 0.5 μm to 11 μm on the phase compositions, texture degree, bending strength, fracture toughness and thermal conductivity of hot-press sintered h-BN-MAS composite ceramics were investigated. Larger h-BN grain can facilitate the nanocrystallization of MAS phase due to the inhibiting crystallization effect of h-BN on α-cordierite. Texture degree of h-BN-MAS composite ceramics increased significantly with increasing raw h-BN particle size, and the 11.0μmBN-MAS composite ceramic shows typical textured structure. The h-BN-MAS composite ceramics show anisotropy in mechanical properties and thermal conductivity, and the anisotropy increased significantly with increasing raw h-BN particle size. The 0.5μmBN-MAS sample shows excellent mechanical properties, and the 10μmBN-MAS sample shows strong anisotropy in thermal conductivity.