Chemical Film Coatings
Metals conversion coatings are an inexpensive solution to prevent aluminum from oxidizing. They make excellent primers for painting and can stand alone as highly corrosion-resistant metal surface coatings. Though primarily used for military/defense and aerospace applications, customers in all industries can benefit from chemical film coatings on their parts and components.
Light Metals Conversion Process
The chemical film deposition process starts as a chemical conversion coating in which the chemicals involved react with each other naturally, without the addition of electricity or other outside influences. The resulting protective film coating passivates aluminum and aluminum alloys—the only materials that can receive this type of metal surface coating—neutralizing their atoms to prevent corrosion.
Specific Light Metals Conversion Coatings
Chemical film coatings such as Alodine® 1000 (clear) and Alodine® 1200 (gold) are used for lighter coatings, while coatings such as Alodine® 1200 are used for darker coatings and provide better corrosion resistance. These metals conversion coatings are generally specified as either “clear” or “gold.” We offer both to meet our customers' needs.
Alodine® 1000 (Clear)
Alodine® 1000 light metals conversion coatings are a liquid chemical used to produce a protective coating on aluminum and aluminum alloys. The coating provides protection for aluminum and provides an excellent bond for organic coatings. This metal finishing product develops a clear or colorless protective coating and it should be used when the characteristic aluminum appearance or finish must be retained.
Alodine® 1200 (Dark)
Alodine 1200 is a chemical film coating that is used to produce a protective coating on aluminum which minimizes corrosion and provides an improved bond for paint. Surfaces treated with the Alodine® 1200 process range in color from a light iridescent golden to tan.
Chemical Film Coating Specifications
Our chemical film coating process meets mil-spec MIL-DTL-5541F requirements. This classification requires aluminum parts to remain in the chemical film solution for a specific length of time. There are variations, depending upon the Class and sub-Class of the mil-spec. We can adjust our metal surface coating processes to meet any mil-spec or industry specifications our customers require.
Improved Corrosion Control
Improving corrosion control is a significant technical challenge that must be addressed before lightweight metal alloys of aluminum and magnesium can be more widely used. Use of lightweight metal alloys would provide many advantages for manufacturing industries such as:
- Metal Finishing
- And More
Currently, chromate conversion coatings based on hexavalent chromium (i.e., chromates) are used to develop corrosion-resistant films on aluminum and magnesium alloys. These films also promote the adhesion of subsequent coatings (e.g., paints) to give a highly effective corrosion-control coating. Chromates, including hexavalent chromium have been demonstrated to be potent mutagens and are considered to cause cancer in humans. Caution should be taken when handling this product, including using safety products and procedures.
Preventing Aluminum Oxidation
The most appropriate ways to prevent aluminum oxidation are through anodizing or clear coating. Multiple approaches exist because there is no one best approach for all conditions. Anodizing may be appropriate for some and clear coating may be more effective for others. However, the most economical way to prevent aluminum oxidation is through a clear coat.