Investigation of microstructure and performance of C/W multilayer coatings with W interlayer

C/W multilayer coatings with W interlayer were deposited on steel substrates using unbalanced magnetron sputtering. The surface morphology, phase composition and cross-section microstructure were analyzed by SEM, XRD and TEM method. The tribological property and adhesion of film to substrate were tested. The results show that the coating is a composite coating composed of amorphous carbon and nanocrystalline WC, which has a clear multilayer structure with a periodical thickness of 6.5 nm. The friction coefficient decreases with the increasing in substrate bias, the coatings deposited at-90V bias have the lowest friction coefficient, the value is 0.14. Thickness of W interlayer is 500 nm, the use of W interlayer does not enhance the adhesion of film to substrate due to the generation of high compressive stresses in W interlayer.