Influence of sintering temperature on the crystallization and mechanical properties of BN-MAS composites

A type of boron nitride–magnesium aluminum silicate (BN-MAS) composite ceramics was fabricated by hot-press sintering at different sintering temperatures. The relationship between the sintering temperature and microstructure was investigated by analyzing the interaction between hexagonal boron nitride (h-BN) and the MAS phase. The main MAS phase in the composite ceramics is the α-cordierite phase at a sintering temperature of 1300°C. At temperatures above 1400°C, the inhibitory effect of h-BN on the crystallization of the MAS system is significant, and MAS mainly exists in the form of an amorphous phase. The composite sintered at 1700°C exhibited the highest bending strength of 218MPa. h-BN and MAS were co-enhanced. MAS can be used as an effective liquid-phase sintering aid to assist in the sintering of h-BN, whereas h-BN can absorb the fracture energy of the composite ceramics through the pull-out and bridging effect of the particles.