Abstract
Hexagonal boron nitride-containing composites demonstrate excellent resistance to thermal shock, mechanical shock and molten metal corrosion. For application as break rings for horizontal continuous casting of steel, BN composites must have balanced comprehensive properties. Increase BN content will enhance the thermal shock resistance but degrade the wear resistance. Even by hot pressing, however, high densification of the h-BN-containing composites is not easy to be achieved when conventional processing is used. In this work, we have obtained high-densified BN composites with high BN content by in situ process. The obtained composites showed high strength and good wear resistance to steel as well as good thermal shock resistance. The example of material system in the present work is Al 2 O 3 -AlN-AlON-BN. The in situ reactions between aluminum borates and nitride are used to synthesize BN phase in the Al 2 O 3 -AlN-AlON matrix.
