Synthesis and properties of new β-Sialon/TiN composites via a novel AlxTiy intermediate

A new synthesis of β-Sialon/TiN composites by reaction bonding of aluminium powder coated with nanosized titania is reported. A sol–gel method was used to coat the aluminium particles with titania and the resulting powder was calcined in an inert atmosphere to produce a TixAly–Al2O3 composite which was heat-treated in nitrogen to form an AlN–Al2O3–TiN composite. After addition of a suitable silicon phase and yttrium oxide as a nitridation and sintering aid, a β-Sialon/TiN composite was formed by reaction bonding under nitrogen.Young׳s modulus, hardness, fracture toughness, tensile strength and thermal shock resistance of the new composites were measured and compared with a standard β-Sialon fabricated by reaction bonding of Al2O3, AlN and Si under similar conditions.