Research and First-Principles Calculation of ZrxTi1-xC Ceramics Synthesized from Environmentally Friendly Precursors

ZrC and TiC are high-temperature materials that can be used in astronautic and aeronautic industries. Titanium (Ti) and zirconium (Zr) belong to adjacent elements of the same IVB family; their similar chemical properties can form a relatively stable crystal structure. Zr x Ti 1-x C composite ceramics doped with Ti were prepared by precursor pyrolysis method. The precursor of aqueous solution systems is more environmentally friendly than in organic systems. The results show that preparing high-purity Zr x Ti 1-x C composite ceramics can be obtained at the Zr: C and Ti: C molar ratio more than 1: 4. The mole number of C is at least four times than the metal ions Zr 4+ or Ti 4+ . The maximum phase transformation temperature is 502.3 °C in Zr 0.25 Ti 0.75 C, which is significantly higher than the initial oxidation temperature 460 °C of ZrC. The result indicates that the Zr x Ti 1-x C composite ceramics reinforced by Ti have better oxidation resistance than pure ZrC ceramics. The crystal structure and bonding properties, electronic characteristics, phonon dispersion spectrum and dynamic stability, mechanical property, and thermodynamic properties of Zr x Ti 1-x C are calculated using first principles showing that Zr 0.25 Ti 0.75 C is the best material.