As metal coating is characterized any method or surface processing, which aims at the deposition of a layer of metal or alloy on the surface of a material.

The processes of coating are generally categorized in electrolytic and electroless plating depending on whether external current is being used or not. The superficial processing comprises of chemical and electrochemical reactions, metal and chemical coating.

The main processes for metal coating are electrolytic and electroless plating, anodization, galvanization and vapor deposition.

The finishing of metallic and non-metallic materials usually takes place in three stages, where the material goes through baths that contain the necessary chemical agents:

Surface preprocessing The quality of the coating significally depends on the condition of surface that is going to be coated. For this reason, it is essential to remove oxides (rust), greasy substances, oils etc, before proceeding on the coating. It should be noted that cleaning the surface leads to "its activation", which means that it has higher receptivity for the coating material.

Surface processing In this stage the change of the product's surface with its coating takes place. In order to achieve the desired attribute, the product pass through a row of baths which contain the suitable chemical agents. After each coating the object is rinsed so as to clean it from the bath solution.

Surface meta-processing The processes that follows the coating of the product have as main purpose to provide it with further properties or to improve its appearance.