What Is Electropolishing?
Electropolishing otherwise known as anodic polishing, electrochemical polishing, and electrolytic polishing (particularly in the metallography field) is an electrochemical process which removes material from a metallic product. By leveling the micro-peaks and valleys electropolishing reduces the roughness of the surface and improves the overall finish of the surface. It is used to deburr, passivate and polish metal objects and parts. The process does not deform the layers of the surface.
Most metals can be electropolished. The most common are aluminum, copper, stainless steel, titanium, and nickel and copper alloys.
The metal part is immersed into an electrolyte bath, which is temperature controlled and serves as the anode, which is connected to the positive terminal of the DC power supply. The cathode is attached to the negative terminal. As the anode is oxidized and dissolved in the electrolyte, a current passes from the anode to the cathode. A reduction reaction occurs, producing hydrogen at the cathode. To successfully electropolish a rough surface, it is essential for the protruding parts of the surface profile to dissolve faster than the recesses. For electropolishing to be successful following the current dependence on voltage with consistent stirring and temperature control is needed.