Fabrication and properties of Sialon-ZrN composites by two-step sintering

摘要

The effect of two-step sintering on the fabrication and properties of Sialon-ZrN composites has been studied. In the present work, the results showed that composites sintered at different T2 temperature had similar phase assemblage and morphologies. Composites sintered at a higher T2 temperature presented greater relative density and smaller open porosity, and had greater hardness and fracture toughness, achieving a highest hardness of 16.9 +/- 0.3 GPa for 20 wt% ZrN and greatest fracture toughness of 5.4 +/- 0.3 MPam(1/2) for 40 wt% ZrN. In comparison with one-step sintering, composites fabricated by two-step sintering had smaller grain size and more homogenous microstructure, resulting in greater hardness without sacrificing fracture toughness. The electrical properties of the composites were similar regardless of sintering techniques.