Effect of Hf Content on Microstructure and Properties of ZrxHf1-xC Composites

HfC and TiC are high-temperature materials which can be used in astronautic and aeronautic industries. The titanium (Ti) and zirconium (Hf) have the similar chemical properties due to they are in the same IVB family. Zr x Hf 1-x C composites doped with different Hf contents are prepared by pyrolysis of ZrC precursors. The precursor of aqueous solution systems is more environmentally friendly than in organic systems. The results show that prepare high-purity Zr x Hf 1-x C composites can be obtained at the Zr: C and Hf: C molar ratio more than 1: 4. The mole number of C is at least four times than the metal ions Zr 4+ or Hf 4+ . All the prepared composites exist in the form of solid solution. The results show that the average particle size of Zr x Hf 1-x C composite ceramic particles is about 100 nm, and the distribution is uniform and dendritic. Zr 0.25 Hf 0.75 C composites can increase the oxidation temperature to 478.6 °C, which is a certain increase compared with the initial oxidation temperature of ZrC of 460 °C. Meanwhile, the first principles simulation showed that Zr 0.5 Hf 0.5 C has the best mechanical property and thermodynamic properties in Zr x Hf 1-x C system, which can provide a future choice for good mechanical properties of block materials.