Abstract: The thermal protection structure was fabricated by co-curing graphite film and BMP350 polyimide composite. The graphite film was fabricated at a temperature of 3 000 ℃, making polar functional groups hardly exist on film surface, which prevents the bonding of the film to the composite. This work improves the surface treatment technique of the graphite file and interface controlling technique. As a result, typical composite plate specimens with thermal protection structure could be made. Nondestructive testing (NDT), test of bonded strength between the film and composite and thermal shock testing were conducted. This structure could pass NDT test, airflow erosion test and thermal shock testing of 400 ℃, 547 h and 800 ℃, 30 min. The pull off failure occurs inside the film. These testing results show the thermal protection structure possesses the potential of engineering application.

Key words: polyimide, thermal conductivity of graphite, high-temperature mechanical properties, thermal protection structure, composites