Anodizing corrosion resistant coatings offer exceptional means for enhancing corrosion protection in the aluminum or magnesium finishing industry. These electrolytic-based films, oxide-based, are highly stable and guard well against atmospheric corrosion.

Property enhancements are made by filling the coatings’ micro porosity. Imagine a deep cellular structure extending inward, through much of the coating formation. Individual cells, with pores down their centers, can total millions per square inch. This makes for excellent absorptive processes.

Once the anodize aluminum is sealed, it is, in effect, non-absorptive. For general corrosion protection, sealing solutions for the ceramic, like de-ionized water, can be ideal for their ability to react with anhydrous aluminum in the outer layers of the film. A mono-hydrate of the oxide is formed, which occupies greater volume than the alumina from which it was formed. The result is a reaction to close down and plug the pore structure.

Other sealing products for anodized aluminum can include steam or sacrificial corrosion inhibitors like nickel acetate. Keep in mind that both materials and processing methods vary. Be sure your service provider fully understands your performance needs.

Today, Teflon (PTFE) and a host of other compounds can be integrated (jointly) for exceptional enhancements in corrosion protection. And while chemical resistance of hard anodize (also known as ‘hardcoat’) is typically poor beyond mild acids and weak bases, performance can be improved.

Keep in mind that surface finish can be equally instrumental in preventing corrosion. There is a correlation between surface finish and protection from corrosion. Consequently, the original finish may require polishing or minimum, examined for surface flaws or imperfections.

Post finishing of the alumina oxide (also referred to as aluminum oxide) may also be desirably, again for enhanced corrosion protection.

These types of coatings can serve as excellent protectors against galvanic coupling corrosion. Keep in mind though, homogeneous forms of aluminum are ideal, since alloying constituents can form undesirable products or less stable oxides. If dimensional builds are no issue, additional layering may be accomplished through paints and other corrosion inhibiting coatings, as they will be well anchored for mechanical bond strength.

These coating processes are compatible with alloys of aluminum or magnesium, only. Consequently, work pieces should be free of dissimilar metal. Though masking may be feasible, there is always risk for ‘burning’, irrecoverable loss in material mass based on catastrophic dissolution.

Anodizing corrosion resistant coatings, for performance, are well suited for atmospheric conditions, salt spray resistance, marine environments, and, chemically, in the presence of many compounds, including weak acids or weak bases.