Decoupled ablation behavior analysis of multilayer glass-UHTC coating for carbon-based composites: Laser and plasma ablation environments

Constructing a dense and continuous oxide scale to resist high-energy laser and high-velocity heat flow remains critical for future carbon-based materials in aerospace field. Herein, a multilayer glass-HfC/ZrC/HfC coating was developed using plasma spraying and hot dipping-painting hybrid method. The high-temperature oxygen blocking of (Hf, Zr)O₂ solid solution, crack healing and micropore sealing of SiO₂-based glass, jointly enhanced the ablation resistance of C/C composites under high-energy laser and high-velocity heat flow. Under high-energy laser ablation environment (39.8 MW/m², 60 s), the self-derived Hf-Zr-Si-O oxide scale maintained dense and continuous structure, outperforming ZrC coating (6.8 μm/s) by about twice. Under high-velocity heat flow (7.26 MW/m², > Mach 1), the Hf-Zr-Si-O oxide scale provided 1080 s protection with low mass and linear ablation variation rates of 0.19 mg/s and 0.16 ± 0.09 μm/s, attributed to improved ablation uniformity of the Hf-Zr-Si-O oxide scale and enhanced pore filling and sintering effects.