The processes for anodizing aluminum are more than 100 years old, and most in the anodizing industry thought we knew all there was to know about anodizing aluminum. Now we have learned that a company in Florida has developed a new way to anodize aluminum.

The process developers, Keith Eidschun and Joshua Cloakey, call the process AlOxidize. The implications of this research and development effort for the corrosion industry are huge.

Primary methods of anodizing aluminum

Understanding the benefits of the AlOxidize process requires a quick review of the three other primary ways to anodize aluminum and what these processes offer.

  • Sulfuric acid anodize (SAA)
  • Hard coat anodize (HCA)
  • Chromic acid anodize (CAA)

Using SAA and HCA, the solution penetrates the aluminum and grows out from every surface of the piece at a ratio of 50/50. The SAA method allows for easy dying and moderate corrosion resistance, and the HCA process causes a dense coating that is much more corrosion resistant than the SAA method.

However, this can present shops with problems that increase waste and cost. Parts that are marginally overanodized often need stripping and anodizing again. Unfortunately, sometimes parts can never recover, and the result is wasted material and manpower.

CAA is very dense and almost immeasurable. The downside is that chromium is highly regulated, environmentally unfriendly, and the end product is fragile without an abrasion rating.

The benefits of the AlOxidize process

Eidschun and Cloakey claim that the AlOxidize process combines all the best features of each existing process. Finished products have the limited growth found with CAA, the superior corrosion and abrasion resistance resulting from the HCA method, and the coloring capabilities of SAA. In other words, the AlOxidize process provides the benefits of standard aluminum anodizing processes without any drawbacks.

"With only 0.0003 inch of coating, we were able to go 800 hours before showing small signs of pits," Cloakley said. "Coatings with only 0.0008 inch of anodic thickness were able to pass back-to-back Taber abrasion testing."

Eldshun and Cloakley patented the new method and claim many benefits for its use.

  • Using this process, the limit of dimensional growth is only 0.00005 inches, it is the equivalent of only 3-6 percent of the thickness of the anodic coating; the process is well suited for situations involving tight tolerances.
  • At current, the process is quick and gets to desired thickness more rapidly than other methods.
    • Anodic thickness comes about at the rate of 0.0001 inch/minute.
    • Meet hard-coat thickness requirements in 15-20 minutes.
    • Sulfuric anodizing results in five minutes
  • The process is less likely to have burning occur and is resistant to other defects caused by too much voltage or amperage.
  • Compared to traditional anodizing techniques, the AIOxidize method is more resistant to surface contaminants, making perfectly clean aluminum unnecessary.
  • The finished products have about two times the anodic coating weight as a traditional SAA coating of the same thickness, as the coating is twice as dense. Therefore, the coating has the highest amount of corrosion and abrasion protection offered by the HCA method. That protective ability occurs with the ease and speed of the SAA method.
  • Coats are thin but strong, so far less architectural detail is lost in the anodizing process.

Industry implications

If this method of aluminum anodizing lives up to its creators' descriptions, then it may change the aluminum anodizing industry forever.

Shops gain productivity by anywhere between six and 12 times, while creating a fine finished product with solutions lasting longer than other anodizing solutions. Due to fewer changes of solution and faster production methods, profitability increases.

Customers get the benefits of all types of aluminum anodizing processes in a single pass. Finished goods are stronger, fit better and take color.