Preparation and Properties of β-SiAlON-cBN Composites Using Y₂O₃, B₂O₃ and Al as Additives

Abstract

SiAlON-cBN composites with different contents of cBN were consolidated by spark plasma sintering (SPS) at 1450°C using Y2O3, B2O3 and Al as additives. The effect of cBN content on the density, phase compositions, microstructures and mechanical properties of β-SiAlON-cBN composites was investigated. With increasing the cBN content, the density and hardness of β-SiAlON-cBN composites decreased. Fracture toughness could increase thanks to the crack deflection resulted from the cBN particles. For β-SiAlON-10 wt% cBN composites, the optimum hardness and highest relative density were 13 GPa and 96.4 %, respectively. For β-SiAlON-40 wt% cBN composites, the highest fracture toughness was KIC = 5.3 MPa∙m1/2.