Electropolishing is an electrochemical process similar to electroplating, but in reverse.
Electropolishing smooths and streamlines the microscopic surface of a metal object, such as 304, 316 or 400 series stainless steel. The resulting surface is microscopically featureless, with no torn surface remaining.
In electropolishing, material is removed ion by ion from the surface of the metal being polished. The fundamental principles of electrolysis and electrochemistry replace traditional mechanical finishing techniques, including grinding, milling, blasting, and buffing as the final finish. In basic terms, the metal object to be electropolished is immersed in an electrolyte and subjected to a direct electrical current. The metal object is maintained anodic, with the cathodic connection being made to a nearby metal conductor.
In addition, the polarized surface film is exposed to the combined effects of oxygen gassing. This occurs with the removal of electrochemical metal, saturation of the surface with dissolved metal, and the agitation and temperature of the electrolyte.