Assessing the origins of corrosion on stainless steels

Abstract

High resolution optical imaging was carried out during the in-situ imaging of 316L stainless steel subject to potentiostatic polarisation. Experiments were performed in a custom open-top 3D printed electrochemical cell. The tested specimens were maintained at a fixed potential of 50 mV below their respective pitting potential in order to produce, and subsequently allow the quantification, of metastable pit formation. Testing was carried out in 0.1 M sodium chloride (NaCl) solution, whilst the electrochemical data and images were simultaneously recorded and analysed to reveal metastable pit characteristics and behaviour. The physical and chemical mechanisms of metastable pit nucleation, growth and repassivation are also elaborated herein. The specimens studied include 316L stainless steel additively manufactured (i.e. 3D printed) by Selective Laser Melting (SLM), allowing a comparison with wrought 316L. Show more