Structure and properties of Si and N co-doping on DLC film corrosion resistance

Three species of diamond-like carbon (DLC) film were systematically examined in NaCl solution for their anticorrosion properties. Si&N&H-DLC has better electrochemical characteristics and salt spray corrosion testing results than the substrate and two species DLC films in NaCl solution. Due to the successive growth of Si, N, and H-DLC, there is a well-bonded Si–N interface and the formation of Si oxides. The Si&N&H-DLC film exhibits extremely high charge transfer resistance, exceeding 10 6 Ω/cm 2 . A salt spray test shows that the Si&N&H-DLC film presents a lower rate in NaCl solution in comparison to the substrate and the other two species of DLC films. As a result, the Si&N&H-DLC film significantly improved the corrosion performance of the substrate.