Thermal Ablation of Stabilized Zirconia/Metal Coated Polyimide Matrix Composites Via Plasma Spray Process

Abstract

Thermal protection coating systems consisting of different bond coats and stabilized zirconia were fabricated on the silica glass fiber reinforced polyimide matrix composites via air plasma spray process. Influence of the different bond coats on thermal ablation resistance of the coating system was investigated. The weight loss of the sample decreased from (7.01 ± 0.42) to (1.93 ± 0.16) %, while the corresponding mass ablation rate of the sample was reduced from 0.48 ± 0.02 to 0.22 ± 0.02 mg s−1, which was attributed to the protection of the coating system with Zn interlayer and partially stabilized zirconia as top layer. After thermal ablation test, failure modes of these coatings were the formation of the cracks or the delamination in the metallic interlayers. Residual stress, thermal stress and further oxidation of the substrate were responsible for the final failure of the coatings.