Electropolishing Behavior of Additive Layer Manufacturing 316L Stainless Steel in Deep Eutectic Solvents

Additive Layer Manufacturing (ALM) presents many design benefits compared to mechanical machining, particularly for complex shape parts. Significant weight and cost savings are achieved because of the production of near-net-shape metallic parts combined with a lower amount of raw materials. However ALM parts suffer from high roughness, worsening the corrosion resistance and the technical endurance. A post-treatment is then necessary to reach mechanical requirements. Electrochemical polishing, usually performed in harmful solutions, appears as a promising technic to reduce surface roughness. The aim of this study is then to develop a sustainable electropolishing process for 316 L ALM parts by using a Deep Eutectic Solvents (DES) as electrolyte. The best electropolishing conditions were first determined on Cast and ALM samples. After electropolishing, both types of sample exhibit bright and smooth aspects, revealing a high roughness reduction. The pitting corrosion resistance of both materials is also enhanced by this process.