Ablation and anti-vibration properties of modified epoxy resin-based ablation thermal protection coatings (ATPCs) in arc-jet

In order to satisfy the requirements of thermal protection for hypersonic vehicles under high temperature and strong scour environment, a quaternary ablation thermal protection coatings (ATPCs) that incorporated micro-sized iron trioxide (Fe2O3) powder, hollow glass microspheres (HGMs) and mica powder into hydroxyl-terminated silicone oligomer-bridged epoxy resins (PSGs) was prepared on stainless steel substrate by a simple spraying method. The ATPCs were well adhered to the substrate and showed a uniform thickness of approximately 1 mm. The ablation behaviors of the ATPCs were investigated in an arc-jet. The aero-thermal parameters of the surface of ATPCs were not uniform, which heat flux ranged from 400 kW/m2 to 700 kW/m2, and the dynamic pressures ranged from 100 to 124 kPa. Results shown that the maximum surface and back-face temperature reached 791.7 °C and 215.5 °C during ablation. In addition to some slender crack, no other obvious structural damage of the ATPCs was found. Furthermore, the structural reliability of the ATPCs under aero-thermal-random vibration (20–2000 Hz, Grms = 12 g) coupled environment was also investigated. The phenomenon of large area peeling of the ATPCs was not observed, which can be ascribed to the enhanced toughness and adhesion of modified epoxy resin. The study provides an important basis for obtaining high-performance ATPC, which is highly desired in hypersonic vehicles.