Investigation of the corrosion and wear failure behavior and mechanism of TiN/Ti multilayer with varying thickness

The poor corrosion and wear resistance of high-strength steel limits its long-term performance in marine environments. This study investigates the effect of multilayer TiN/Ti coating thickness, including 5 μm, 7 μm and 9 μm, on both corrosion and wear resistance, as well as the impact of pre-wear on corrosion behavior. Salt spray corrosion tests showed improved resistance with increasing coating thickness, with 9-μm-thick TiN/Ti coatings demonstrating superior performance. Electrochemical results revealed increases of 45.4 %, 151 times, and 1.5 times in open circuit potential, impedance modulus, and charge transfer resistance, respectively, due to the thicker TiN and Ti layers that block corrosive media. The wear test results showed a significant reduction in wear rate. As the coating thickness increased, the wear rate initially decreased before stabilizing. Specifically, the wear rate of the 9-μm-thick coating was reduced by 33.9 %. Electron backscatter diffraction analysis confirmed a higher density of geometrically necessary dislocations in the coated samples, suggesting enhanced plastic deformation resistance. Furthermore, the electrochemical performance of both the substrate and coated samples after wear was superior to the original substrate and as-deposited coatings. This improvement was attributed to the formation of dense tribo-films, composed of Fe-rich and O-rich oxide layers, which developed during wear and further enhanced corrosion resistance. These findings underscore the effectiveness of multilayer TiN/Ti coatings in improving the durability of high-strength steel in marine environments.