Effect of ion implantation on corrosion resistance and high temperature oxidation resistance of Ti deposited 316 stainless steel

Corrosion and oxidation studies of Ti coated on 316 SS have been performed after 30 keV N2+ ion implantation. Thirty nanometer of Ti was coated on 316 SS by thermal evaporation method. The implantations were carried out at doses ranging from 1×1016 to 5×1017 ions/cm2. Glancing angle X-ray diffraction was used to check nitride formation after ion implantation. RBS and secondary ion mass spectroscopy were employed to find concentration and depth profile of Ti and nitrogen. The aqueous corrosion studies were carried out in 0.5 N H2SO4 and 0.5 N HNO3 solutions. The oxidation resistance studies were carried out in air at 800 °C using continuous and discontinuous method. The oxidation and corrosion resistance increase after nitrogen implantation. The oxidation resistance is maximum at a dose of 5×1016 ions/cm2. It is also observed that the dose affects the initial period of nucleation. In case of aqueous corrosion it was found that corrosion resistance has improved substantially with respect to the untreated substrates. Saturation in corrosion improvement is noticed at higher doses.