Thermal insulation and anti-vibration properties evaluation of modified epoxy resin-based thermal protection coatings in arc-jet

Thermal protection system (TPS) is crucial for hypersonic flight vehicles to effectively protect them against the aerothermal effect imposed on them during flying with high Mach number. A novel hybrid ablation thermal protection coatings (FHMP-ATPCs) on the surface of stainless steel substrate were prepared by doping iron trioxide (Fe2O3) powder, hollow glass microspheres (HGM) and mica powder (MP) into hydroxyl-terminated silicone oligomer-bridged epoxy resins (PSG) copolymer. The thermal insulation and structural reliability of the FHMP-ATPCs were investigated by a novel aerothermal-vibration coupling test system. During the test, the heat flux of the surface of coatings ranged from 400 kW/m2 to 700 kW/m2. Meanwhile, the vibration load was a random vibration with frequency range of 20–2000 Hz and root mean square of total acceleration (Grms) of 10.8 g. The maximum surface and back-face temperature reached 714.9 °C and 141.3 °C, respectively. Compared with epoxy resin based coatings，the PSG-based coatings showed excellent structural reliability during the test. This study demonstrates the robust effect of strategy of modifying epoxy resin with organosilicon in improving thermal insulation performance yet maintaining the structural reliability of the ablation thermal protection coatings, providing a promising route to achieve high-performance coatings.