Synthesis and investigation of structural properties of high-quality niobium disilicon ceramics at high pressure and high temperature

The synthesis of high-quality silicide ceramic has been challenging mainly due to the high melting point of the silicide and the difficulty in achieving a uniform composition. This study reports the synthesis of dense and homogeneous niobium disilicon (NbSi2) ceramics, accomplished with high-temperature and high-pressure (HTHP) technology. The synthesized bulk NbSi2 ceramics were extensively characterized for their microstructures, phase stabilities, and oxidation resistance, along with the effects of pressure on their physical properties, and the results were then compared with first-principles calculations. The microstructures and relative densities of the sample were regulated by the slow-modulated HTHP sintering method, thus significantly influencing the physical properties and thermal stabilities of the NbSi2 ceramics. The findings of the study provide valuable insights into the physical properties of silicide ceramics, th potentially paving the way for the further design and synthesis of multifunctional ceramic materials.