Electrolyte Effect on the Surface Roughness Obtained by Electropolishing of AISI 316L Stainless Steel

Electropolishing is a process for the surface finishing of metals and alloys, achieving brilliant surface finish with very low surface roughness values. The most common electrolytes for the electropolishing of stainless steel are varying concentrations of phosphoric and sulphuric acid, and occasionally additives such as chromic acid. The objective of this study was to assess the performance of three commonly used industrial electrolytes in terms of the surface finish of electropolished stainless steel. Each electrolyte had different concentrations of phosphoric acid, sulphuric acid, and chromic acid. The following electropolishing conditions were assessed: current density, bath temperature, electropolishing time, initial textures, and electrode positions. This study on the performance of three industrial electrolytes for the polishing of stainless steel AISI 316L revealed that adding chromic acid does not significantly enhance surface finish, and electropolishing ranges were quite similar for all three electrolytes.