Novel solid-state diffusion strategy for fabricating boron/nitrogen-containing ternary-anion (Zr,Hf,Ti)(C,B,N) carbide with enhanced oxidation resistance

This work introduces fabricating single-phase ternary-anion carbide solid solution via solid-state diffusion of B and N. Initially, non-stoichiometric (Zr,Hf,Ti)C x with carbon vacancies was synthesized by modified spark plasma sintering. Then, using B 2 O 3 and g -C 3 N 4 as sources, (Zr 0.3 Hf 0.5 Ti 0.2 )(C 0.87 B 0.03 N 0.07 ) with face-centered-cubic structure was produced via B diffusion at 1100 °C and N diffusion at 1600 °C. Trace B (0.23 wt%) and N (0.71 wt%) in (Zr 0.3 Hf 0.5 Ti 0.2 )(C 0.87 B 0.03 N 0.07 ) was found to significantly enhance the oxidation resistance (higher onset temperature 520 ± 3 °C (particle size 2.5 ± 1.3 μm) than 475 ± 3 °C of (Zr 0.3 Hf 0.5 Ti 0.2 )C 0.85 and improve structural stability with more negative binding energy.