Effect of Pulsed Laser Deposition of Thin Surface Film of 316 L Stainless Steel on Corrosion Behaviour of Mild Steel

This paper describes an experimental corrosion study performed on austenitic stainless steel deposited mild steel substrate in 0.5 M sodium chloride medium. The study was performed with an aim to improve the corrosion resistance of mild steel substrate through surface deposition of a thin film of asutenitic stainless steel. The thin SS film was deposited by pulse laser deposition technique while using 316 L grade stainless steel foil as a target. Thin film deposition of 316 L stainless steel on mild steel brought about relative improvement in its resistance against corrosion. However, with respect to 316 L stainless steel foil, the specimen exhibited poor corrosion resitance in terms of corrosion rate (corrosion current density), lack of passivity and pitting potential. The reason for the inferior corrosion behaviour of deposited specimen is attributed to defective ferritic microstructure of the thin film and lack of nickel constituent which was associated with lower resistance and higher capacitance with respect to 316 L stainless steel foil. Similarly, with respect to mild steel, deposited mild steel showed better corrosion resistance due to passive role of chromium enriched film.