Study on the impact erosion wear resistance and damage evolution of TiN films under different impact cycles

Depositing TiN coating is an effective way to improve the erosion resistance of titanium alloy. However, few studies have been carried out to analyze the damage process of TiN coated specimens. In this study, a TiN coating was prepared on the Ti6Al4V by employing a filtered cathodic vacuum arc. The erosion performance and damage evolution of TiN coating were investigated, accompanied by varying the impact cycles from 500 to 10,000. The change of peak impact force and energy absorption rate with increasing impact numbers were analyzed. A white-light interferometer was used to characterize the 3D surface topographies of the damaged surface. Scanning electron microscopy and energy dispersive spectrometer were used to observe the state of the eroded surface. The results show that the sand is embedded in the substrate with the increase of impact numbers. With decreasing the number of impacts, the energy absorption rate of the TiN coating increased rapidly, while the peak impact force decreases rapidly. The formation of impact pits, plow grooves, micro-cutting, brittle spalling, and cracks can be regarded as the wear mechanisms of the samples under sand erosion.