Corrosion behavior, metal ions release and wear resistance of TiN coating deposited on SLM CoCrMo alloy by magnetron sputtering

Abstract

In this study, the TiN coating was successfully deposited on selective laser melting (SLM) CoCrMo alloy via magnetron sputtering technique. The TiN coating microstructure and thickness were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical corrosion behavior, metal ions release and wear resistance of the SLM CoCrMo sample with and without TiN coating was compared. The results showed that there was some macroparticles and pores on the TiN coating surface and the TiN coating thickness was about 1.44 μm. The TiN coating helped the SLM CoCrMo sample to reduce the corrosion current density from 19.1nA/cm2 to 8.12nA/cm2 and improved the corrosion resistance but not significantly. Then, an explanation of the corrosion resistance changes of the TiN coating was given. In addition, the TiN coating could prevent the metal ions release such as Co, Cr and Mo of the SLM CoCrMo sample at short time immersion but lost the protecting effect at long time immersion due to the corrosion damage of the TiN coating. Furthermore, compared to the SLM CoCrMo sample, the TiN coating was conductive to improve the wear resistance only at lower normal load (5N) but had similar wear resistance at higher normal load (10N and 30N). The reason was mainly attributed to the thinner TiN coating thickness and higher load led to the failure of the TiN coating.