Corrosion of Binder Jetting Additively Manufactured 316L Stainless Steel of Different Surface Finish

One technique of additive manufacturing is the binder-jetting technique that has the advantages of low costs, printing at room temperature and in air, and no need of a support structure. The aim of this study was to investigate the corrosion behavior of printed 316L surfaces with and without different post surface treatments of blasting and superfinishing. Comparative studies were performed on abraded wrought 316L. Surface topography, porosity, surface oxide composition, and electrochemical characteristics, including pitting corrosion, were investigated at room temperature as a function of post surface treatments in diluted hydrochloric acid at pH 1.5. The blasting and superfinishing treatment significantly reduced the surface roughness and level of surface porosity. Blasting detrimentally affected on the pitting corrosion resistance. The superfinishing process induced an enrichment of chromium in the surface oxide and improved the pitting corrosion resistance. All surfaces revealed slightly reduced susceptibility to pit initiation and metastable pitting as compared to wrought 316L, possibly explained by the absence of inclusions. Once pitting propagation was induced, repassivation was hindered for all surfaces compared with the wrought surface. The pitting corrosion resistance of the as-superfinished 316L was improved compared with wrought 316L.