Pressureless sintering behavior and mechanical properties of ZrB 2–SiC composites: effect of SiC content and particle size

摘要

In the present paper, ZrB2–SiC composites were prepared by pressureless sintering at temperatures of 2000–2200°C for 1h under argon atmosphere. In order to prepare composite samples, ZrB2powder was milled for 2h, then the reinforcing particles including of micron and nano-sized SiC powder were added. The mixtures were formed and, after the pyrolysis, they were sintered. Densification, microstructural and mechanical properties of ZrB2–SiC composites were investigated. The shrinkage of samples was measured both before and after the sintering, and the microstructure of samples was examined using scanning electron microscopy (SEM), equipped with EDS spectroscopy. Both mass fraction and size of SiC powder have a great effect on relative density, porosity, shrinkage, hardness and microstructure of these composites. The highest relative density and hardness were 98.12% and 15.02GPa, respectively, in ZrB2–10wt% SiCnanocomposite sintered at 2200°C.