Preparation and Characterization of Si_3N_4/TiCN Composite Ceramic Tool Material

摘要

Si_3N_4-based composite ceramic tool materials reinforced with TiC_(0.5)N_(0.5) particles were fabricated by using hot-press-sintering technique with Al_2O_3 and Y_2O_3 as sintering aids. The effects of the content of TiC_(0.5)N_(0.5) on the microstructure and properties of composite ceramic were investigated. The experimental results show that optimal mechanical properties were achieved for the composite with the addition of 20 vol.% TiC_(0.5)N_(0.5) microparticles, with the flexural strength, fracture toughness and Vicker's hardness being 838 MPa, 8.5 Mpa·m~(1/2) and 15.6 GPa. The fracture surface microstructure of the composites is characterized by scanning electron microscopy (SEM). Phase identification was carried out by X-ray diffraction (XRD). It was found that the microstructure of the material was homogenous and the elongated grain of β-Si_3N_4 was interlaced. And the fracture surfaces were observed to exhibit a mix of intergranular and transgranular fracture.