Inhibiting crystallization mechanism of h-BN on α-cordierite in BN-MAS composites

MAS-BN composites were prepared by hot pressed sintering. The phase transformation of magnesium aluminum silicate ceramic (MAS) was investigated with special attention to the inhibiting crystallization mechanism of h-BN. The resulting data suggest particular pathways for the inhibiting effect of h-BN on the crystallization of MAS. The nucleophilic attack of N on M (M = Mg2+, Al3+ and Si4+) and electrophilic attack of B on O are the crucial factors for the formation of amorphous MAS phase. In addition, a chemical bonding formed between h-BN and MAS and the atoms of the matrix diffuse into the h-BN layer, leading to a strong bonding interface.