Study of the Microstructure, Physical and Mechanical Properties of Zirconium Disilicide Ceramics: Synthesis, Experimental Characterization and Theoretical Calculations

Zirconium disilicide (ZrSi₂) is often used in high-temperature applications due to its excellent mechanical properties and thermal stability. This study aims to investigate the microstructure and physical and mechanical properties of ZrSi₂ ceramics prepared under high-pressure and high-temperature (HPHT) sintering conditions. The research results show that the density, Vickers hardness, and fracture toughness of the ZrSi₂ ceramic sample reach 4.7 g/cm³, 10.547 GPa, and 6.905 MPa·m^1/2, respectively. It is worth noting that the ZrSi₂ ceramic sample exhibits excellent oxidation resistance and its oxidation starting temperature is 1463 °C. The experimentally measured thermal diffusion coefficient of the ZrSi₂ ceramic sample is 2.815 mm²/s, and the specific heat capacity is 0.48 J/g·K, from which the thermal conductivity is calculated to be 6.354 W/m·K. The first-principles calculation results show that the crystal structure of ZrSi₂ has good dynamic stability, and the silicon atoms and zirconium atoms are connected by strong covalent bonds. At the same time, the ZrSi₂ ceramic sample obtained in this experiment has a uniform grain size distribution, a high dislocation density, and a strong texture. The results of this study are crucial for the preparation and application of ZrSi₂ ceramics.