Influence of bond coat on shear adhesion strength of erosion and thermal resistant coating for carbon fiber reinforced thermosetting polyimide

Arc-sprayed Al, Zn, and plasma-sprayed Al, Zn, Ni3Al and Cu were deposited on carbon fiber reinforced polyimide substrate as bond coats for erosion and thermal resistant coating. Shear adhesion strength of different materials was tested, and microstructures of bond coats were analyzed with scanning electron microscope. The results showed that the substrate was thermally damaged when Ni3Al or Cu was deposited as bond coat, and the bond coat was delaminated from the substrate. Arc-sprayed and plasma-sprayed Al and Zn could be used as bond coat materials. For Zn as bond coat material, depositing method had little influence on shear adhesion strength. While for Al as bond coat material, plasma spray was superior to arc spray. Preheating could improve shear adhesion strength with plasma sprayed Al as bond coat. The maximum shear adhesion strength obtained in this paper was 14.15 MPa, with plasma-sprayed Al as bond coat, and the preheating temperature was 250 °C.