Investigation of HfB2 on microstructure of ZrB2-based ceramics prepared by SPS

Spark Plasma Sintering (SPS) is a new technique which was used for sintering of Ultra High Temperature Ceramics (UHTCs) recently. In this study، ZrB2-based ceramics was prepared with different HfB2 content (0، 5، 10، 15 vol%) by SPS in different temperatures، times and pressures. Microstructure evaluation and phases were done by SEM and EDAX. Effect of SPS conditions (temperature، time and pressure) on microstructure was investigated. The results showed that Hf and Zr diffuses in each other and (Zr،Hf) B2 solid solution will be formed. In addition، it was concluded that by increasing temperature and time، solid solution formation increases. Pressure has little effect on diffusion. MoSi2 improves diffusion by liquid phase formation. Finally it is cleared that HfB2 increases open porosity percent slightly.