Corrosion and tribocorrosion behavior of Ti/TiN PVD coating on 316L stainless steel substrate in Ringer's solution

Using physical vapor deposition technique, Ti/TiN coating was deposited on 316L stainless steel with 2 μm thickness. The analysis showed the formation of Face Centered Cubic crystalline structure of TiN with (220) preferred orientation and a hardness of ∼2600 VHN. The results also revealed that Ti/TiN coating not only improved the corrosion resistance of stainless steel in Ringer's solution at 37 °C, but also increased the breakdown potential significantly. Tribocorrosion tests at open circuit potential demonstrated that both stainless steel and Ti/TiN coating samples become repassive after the sliding is stopped. This indicated their ability to repair of passive film in wear scars after sliding. On the other hand, for stainless steel, a significant rise in current was noticed at the beginning of the sliding in anodic potentiostatic tribocorrosion test, indicating a high degree of anodic dissolution. However, the lost volumes of Ti/TiN coated sample in open circuit potential, anodic and cathodic conditions were lower than those for stainless steel, due to its higher hardness and corrosion resistance. For Ti/TiN coated sample, the effect of synergy between wear and corrosion was more important than mechanical wear and/or anodic dissolution.