Zeynab Nasiri - Faculty of Materials & Manufacturing Processes, Malek-e-Ashtar University of Technology, Tehran, Iran
Mehri Mashhadi - Faculty of Materials & Manufacturing Processes, Malek-e-Ashtar University of Technology, Tehran, Iran

In the present paper, ZrB2-SiC was developed by pressureless sintering method and SiC powder at nano and micro-sized scale was used as reinforcement phase. In order to produce composite samples, the primary powders were milled and blended and then processed using hot pressing, CIP, Pyrolysis and sintering. The values of relative density, porosity and shrinkage of samples were measured to evaluate the effect of adding nano and micro-sized SiC powder particles on pressureless sintering behavior of ZrB2-SiC. In order to compare the microstructure and mechanical properties of samples we used Scanning Electron microscopy (SEM), equipped with EDS spectroscopy, XRD analysis, hardness and toughness tests. The results show that in both cases, as the weight percentage of SiC increases, the hardness, toughness, relative density and shrinkage initially increase and then decrease. The only difference is that samples containing SiC nano-particles reach the maximum hardness, toughness, relative density and shrinkage at a lower percentage of reinforcement phase.

Ultra high temperature ceramics, Pressureless sintering, mechanical properties