Passivation electrolytic process used to increase the thickness of the natural oxide layer on the surface of metal parts. This finish is used on aluminum to generate an artificial protection layer through the protective oxide of aluminum, known as alumina. The coating is achieved by electrochemical procedures, and provides greater strength and durability of aluminum. Protection will largely depend on the thickness of this layer (in microns µm) ranging from 5 µm to 20 µm that affect the environment in which they are to be used.