A conversion coating is a treatment process that is used on metal surfaces to provide protection from wear and corrosion. It also serves as a primary layer for the application of paint, dye, lubricant, or adhesive to help those substances adhere to the base. Conversion coating can also be used to achieve a decorative finish on metal.
The coating is called a conversion coating because it involves using a chemical or electrochemical process to convert parts of the metal surface into the finished layer. The conversion coating can be created using oxide, phosphate, or chromate.
Oxide conversion coatings can be used to provide a finish that is decorative and resistant to corrosion. These types of finishes include gun bluing, black oxide and anodized treatments. For a more specialized finish, phosphate and chromate conversions can be used. Phosphate and chromate conversion coatings help to increase resistance against wear, improve conduction, and provide a base layer for paint, adhesives, or lubricants.
Conversion coatings are used for a couple of primary reasons: to alter the appearance of the metal and to provide additional characteristics to the metal. It can be used on a variety of metals, such as steel, brass, copper, and aluminum to enhance their surface characteristics.
Oxide conversion coatings are usually used on iron alloys, like steel. The metal surface is exposed to chemicals. The reaction of the chemicals and the metal results in the formation of an enhanced oxide layer. This creates resistance, dimensional stability. It also provides a more receptive base for paint. Oxide conversion coatings are often used on items like tools, firearms, and bearings.
Phosphate conversion coating is sometimes known as Parkerizing. This is a matte grey coating that can be either sprayed onto an item or bathed onto the item being treated. Phosphate conversion coatings are often used on vehicles and household appliances.
Chromate conversion coatings provide a clear or yellow coat on the metal surface. They offer resistance to corrosion and provide a conductive surface for electricity.
Alodine.® is a clear, non-chromate containing conversion coating product from Henkel that is used as an adhesion promoter and pretreatment for aluminum substrates.
Springco Metal Coating has the ability to e-coat or powdercoat over Alodine®. or provide the part with Alodine®. for the customer to apply a coating of their own.
Springco Metal Coating can coat parts with a profile of 72” x 24” x 36”