Ablation and Anti‐Vibration Behavior of Modified Epoxy Resin‐Based Thermal Protection Coatings With Step Structure Under Aerothermal‐Vibration Coupling Environment

ABSTRACT The ground test of the thermal protection system (TPS) under simulated service conditions is essential for its application in hypersonic vehicles. Novel ternary thermal protection coatings (HMP‐ATPC) with a step structure, incorporating hollow glass microspheres (HGM) and mica powder into hydroxyl‐terminated silicone oligomer‐bridged epoxy resins (PSG), were evaluated using an aerothermal‐vibration coupling test system. During the test, the average heat flux on the coating surface was approximately 50 kW/m 2 , the total enthalpy of the airflow was 21.3 MJ/kg, the synchronous loading vibration frequency ranged from 20 to 2000 Hz, and the total acceleration root mean square (Grms) was 10.8 g. The results demonstrate that the peak surface temperature in the step region reached 966.1°C, significantly surpassing the temperatures observed in other areas of the same coating. Furthermore, during the early stages of the ablation process, the surface temperature across different regions exhibited substantial fluctuations. Along the airflow direction, the temperature on the back surface of the coating decreased from 380.7°C to 304.8°C. Notably, the coating with the step structure showed no signs of peeling after the tests, indicating its excellent vibration resistance. This study provides a critical foundation for developing high‐performance hetero‐structural ATPC systems required for hypersonic vehicles.