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  • The secondary finishes shown, are common finishes by our customers. However, SKS will gladly quote other finishes upon request.

Alodine / Chem Film


Gold Alodine


Clear Alodine

Alodine, also commonly known as chem film, is a chromate conversion coating that is used to prepare aluminum surfaces for the application. Alodine comes in a clear or a “yellow or gold” coating. Before the aluminum can receive the metal finishing, it should always be given the proper chem film treatment to ensure that the coating will be able to form a powerful bond with the metal surface and avoid a premature failure of the bond.

As a chemical conversion coating, Alodine works to fundamentally change the chemical properties of the surface, making it less susceptible to corrosion and more capable of bonding with a metal finishing product. The pretreatment achieves these ends through a process known as passivation, in which the metal surface is made less prone to be affected by oxidation by the elements, includingwater and air. Aluminum that has been treated with chem film is far less likely to oxidize over time, and can therefore be expected to last longer.

Alodine offers major advantages over other types of passivation techniques. Alodine does not inhibit electrical conductivity in parts that are required to pass a current and in parts with dimensions having tight tolerances. Alodine is also used as a protective coating and/or priming prior to applying another finish such as powder coating.

Gold Alodine, although still available through SKS, has been eliminated from future projects because it does not pass the RoHS requirements. Clear Alodine is still available without any RoHS conflicts.