Investigation on cavitation erosion of diamond-like carbon films with heterogeneous multilayer structure

Abstract

Cavitation tests of three heterogeneous multilayer diamond-like carbon (DLC) films (Ti/DLC, TiCx/DLC and Ti-TiCx/DLC) were performed using a vibratory test rig to evaluate their cavitation erosion resistance. Results indicated that the cavitation erosion of multilayer DLC films resulted from flexural cracks in the bending regions, then fatigue failures were developed along the uplifted regions of the films. Comparing to TiCx/DLC film and Ti-TiCx/DLC film, Ti/DLC film had the lowest average erosion area. It was concluded that multilayer structure with titanium as adhesion layer improved the adhesion strength and reduced the plastic deformations of the DLC films in the incubation phase; these Ti layers also decreased the residual stress of the DLC films and reduced the cracks within the films in the attenuation phase; lower ID/IG ratio could improve the fatigue resistance of the multilayer films in the steady phase.