Enhancing corrosion resistance of additively manufactured 316L stainless steel by fabricating pillar arrays

Abstract

By using the electrochemical etching technique, pillar arrays with a size of ∼50–200 nm are fabricated on the surface of 316L manufactured by laser powder bed fusion. The nanopillars morphology is induced by the selective anodic dissolution of dislocation cell walls that are decorated with high local concentrations of Cr/Fe/Ni solute atoms. The appearance of pillar arrays extends the passivation range and increases the pitting potential of 316L in HNO3 solution, while the corrosion current density decreases in NaNO3 solution. The enhanced corrosion resistance was attributed to the coeffect of elimination of corrosion-sensitive features and hydrophobicity prompted by electrochemical etching.