Metal finishing Q&As since 1989

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Coatings for titanium fasteners in salt water

Does anyone have suggestions for coatings for titanium fasteners? The titanium needs to be coated because it is in contact with a dissimilar metal (aluminum) and will be submerged in salt water.

Sam C [last name deleted for privacy by Editor]
- Manassas, Virginia, USA
2004

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YOU CAN ANODIZE TITANIUM IN H2SO4 , AS ALUMINIUM, AND IF YOU LIKE YOU CAN NICKEL STRIKE AND GO FOR ANY PLATING YOU WANT, REF BOOK , AND TRIED. P.S. ANODIZE FOR APPROX. 5 MINUTES , AROUND 1.5 AMP/SQ.DM.

Khair Shishani
aircraft maintenance - Al Ain, UAE
2004

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2004

Anodizing Titanium in an alkaline bath to the AMS 2488 should be a better option than color anodizing Titanium in sulfuric acid bath, as the color anodizing does not have a lot of physical properties that would discolor when handled with bare hands.

The alkaline anodizing process would form a Titanium oxide film that penetrates the base metal at a thickness range of 0.0002 - 0.001", It also hardens the metal surface for abrasion resistance. In addition, there is a proprietary additive that makes the coating lubricative for heavy loads wear. In combination with a Teflon impregnated process, the coating would increase the wear life of the anodize and for salt water application, be a barrier coating that would serve as an added protection from halogen/chloride attack on titanium. The Teflon would also serve as a release compound that would prevent Algae, barnacles or other undesirable sea creatures from adhering to the hardware.

B. Milla
- Huntington Beach, California