Plasma sprayed ceramic coatings for the thermal protection of carbon fiber reinforced plastics (CFRP): Thermal and mechanical properties of YSZ, aluminum titanate, cordierite and mullite coatings

Carbon fiber reinforced plastic (CFRP) is widely used in lightweight applications because of high values in specific strength and rigidity. However, the use is limited due to a low resistance against wear, low values in hardness and a low thermal resistance. The application of a ceramic TBC can protect the underlying CFRP and thus enhance the temperature resistance when a thermal load is applied. In the present study, Yttria stabilized Zirconia (7YSZ), Aluminum Titanate, Mullite and Cordierite were applied onto CFRP with cyanate ester resin based matrix by atmospheric plasma spraying. Aluminum was used as bond coat material to ensure adequate adhesion of the coatings on the CFRP. Thermal and mechanical properties of the coatings, such as Young's modulus, hardness, porosity, coefficient of thermal expansion, thermal diffusivity and phase composition were measured. The properties of the ceramic coatings were used to evaluate the materials as a potential thermal protection for CFRP substrates. The results show that Cordierite coatings contain a high amount of amorphous phase and have the lowest thermal conductivity as well as the lowest coefficient of thermal expansion among the investigated material systems.