Thermal spray coating was applied onto fiber reinforced epoxy composite substrates in order to protect the material from erosion and thermal degradation. The coating process was done by applying monolithic and composite Al based bond coats and Nickel based interlayers by Air Plasma Spray system. Finally, YSZ ceramic top coat layer deposited by APS. Consequently, the effects of surface roughness and volume fraction of reinforcements in composite bond coat layer on coating adhesion strengths was evaluated. During sand blasting process, it was found that there is an optimum surface roughness to gain maximum adhesion strength. This condition can be achieved by proper combination of erodent particles size and blasting pressure. Also it seen that it is necessary to deposit a bond coat of low melting point material before spraying ceramic coating on epoxy based composite. By this way thermal decomposition of polymer material at substrate surface during spraying can be avoided and coating process can be done successfully. Since negative effects of residual stress on coating properties, gradient of thermal expansion must be controlled through coating thickness. Thus a composite bond coat used instead monolithic one and effect of reinforcement volume fraction evaluated; also to control Coefficient of thermal expansion mismatch between top coat and bond coat, two nickel based interlayers were applied between them. Thickness and combination of these two interlayers was selected based on literatures. Finally, coated and uncoated substrate materials were tested against erosion and thermal degradation. Erosion test done at worse condition for thermally sprayed coatings, hardest erodent particles with angular shape was selected. Results shown that Ni based interlayer as top coat can cause more erosion protection than Bond coat and ceramic top coat materials. Also Ni base coated composite show material loss less than two folds than uncoated substrates. Ceramic top coat lead to decrease in material mass loss due to thermal degradation more than two folds in comparison with uncoated epoxy composite. Also presence of ceramic coating at surface of polymer composite lead to decrease in experienced temperature by composite material up to 75 degrees. Keywords : Thermal Spray, Polymer Matrix Composite, Air Plasma Spray, Thermal Barrier Coating
