Novel Hf_xTa_1-xC solid solution nanowire toughened HfC coating: An effective strategy for synchronous enhanced mechanical and anti-ablation performance

Ultra-high temperature ceramic nanowires have offered increasing potential for thermal structural components. Herein, a novel single-crystal Hf_0.5Ta_0.5C solid solution nanowires were synthesized and incorporated with HfC coating, constructing a robust structure with Hf_0.5Ta_0.5C solid solution nanowires uniformly distributed and interconnected within the coating. The novel Hf_0.5Ta_0.5C solid solution nanowires could effectively hinder crack propagation through crack tip pinning and crack deflection. This mechanism substantially enhanced the elastic modulus and fracture toughness of HfC coating by 53.29 % and 59.67 %, respectively. The toughened HfC coating displayed superior fracture toughness and good interfacial binding strength with substrate to resist sever oxidation and scouring. Additionally, the high thermal conductivity of toughened HfC coating could promote the heat transmission that the coating sustained. Thus, in comparison to pure HfC coating, the toughened HfC coating displayed smaller mass and linear ablation rates of -0.35 mg·s^-1 and -0.46 μm·s^-1, which decreased by 39.66% and 36.98%, respectively. Our work not only simultaneously enhances the mechanical property and ablation resistance of HfC coated carbon/carbon composites, but also provides a novel prospect for advanced ultra-high temperature ceramic nanowires under extreme condition.