Chemical polishing, also known as chemical polishing or etching, is a process for producing gloss and smoothing of metal surfaces by electroless exposure to suitable solutions. Chemical polishing is used not only for decorative purposes, but also to improve heat and light reflection (in infrared radiators, spotlights and similar). Chemical polishing can also have a positive effect on electrical properties (cold emission, characteristic impedance).
Although gloss solutions have been developed for many metals, the process is mainly used for aluminium, copper and copper alloys as well as austenitic stainless and acid-resistant steels, and to a lesser extent also for carbon steels. A homogeneous microstructure is important for the success of the treatment. The process is similar to electrolytic polishing, but instead of a current applied from the outside, an internal current is generated by local elements.