Surface Crack Analysis of TiN Coating in the Sliding Friction Contact Conditions

In order to reveal the failure mechanism of TiN coating, the simulations of scratch process with finite element method are carried out. Meanwhile, the stress analysis was carried out on the three stages that stylus tip indenting coating surface, slipping on coating surface and rising from coating surface. Through the observation of simulation results and the analysis of the stress shows that there are two ways of forming coating surface cracks. One is that coating interface cracks are firstly induced, thus they are propagated to the coating surface, and finally the surface cracks are formed. Other is that cracks are directly formed in coating surface. Because they are induced by maximum tensile stress, surface cracks are modeI.After stylus tip rising from coating surface, biggish residual stresses remain in the coating. Those analyses will supply the basis of coating design and application.