ABSTRACT
BN has been regarded as a promising material for structural applications due to its unique properties, including extremely high melting temperature, good solid-state phase stability, no wetting with metal, solid lubricant, excellent thermal shock resistance, chemical inertness, non-toxicity and environmental safety (Lipp et al. 1989). BN is also a machinable material (Li et al. 2005). It can be widely used in the metal industry, high-temperature furnaces, insulator and continuous strip casting. However, the low mechanical properties and high-thermal conductivity of BN materials have severely limited their applications. Adding second phase to the BNmatrix is a very useful method for improving the mechanical properties of BN materials. The second phase can be oxide (Li et al. 2002), nitride (Wang et al. 2002, Jung & Baik 2007), boride, or carbide (Kusunose et al. 2007; Jiang et al. 2008). ZrO2 and ZrB2 have highmelting point, good hardness good solid-state phase stability, no wetting with metal and chemical stability, and also used as refractory materials for steel industry.BNcomposites incorporatedwith monoclinic zirconia have been used in steel production as a side-dam material for thin-strip casting and a break ring for horizontal continuous casting (Eichler& Lesniak 2008; Vikulin et al. 2004).
