Letter 27014

Post-phosphate oil or other material sought  

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We are working on a process to increase the corrosion resistance of hard coatings on steel. Our patented process involves three steps. Step one is to deposit by PVD a hard coating on the steel, TiN or the like. While these coatings are themselves very corrosion resistant, there are always holes in the coating where the base steel is exposed. In the second step, we phosphate the samples, in effect phosphating the exposed steel in the holes. In the third step, we apply an oil which is absorbed by the phosphate. The oil on the hard coating is then wiped away. In practice, the hard c

oating protects the phosphated, oiled surface in the holes, while the overall surface remains corrosion free. We are not experts in phosphating or post-phosphate treatment, so would like to know if someone has a product that is particularly good to use on phosphated surfaces.

Jim Treglio
- San Diego, California

If you can find a decorative chrome plating shop that you don't lock horns with, they may give you advice, Jim. It is fairly common for shops that chrome plate tubing to then phosphatize and oil dip it to protect the inside of the tubing (which is unplated) from rusting. But supporting advertisers who vend this product will also probably be glad to help.

Ted Mooney, P.E.  finishing.com Brick, New Jersey

We use several different oils on phosphated parts. One of them is Mobil's Mobilarma LT or MT, the other is Henkel's Geracor FC 504. Both have a corrosion resistance of 48-72 hours at DIN 50021 Salt spray test.

Sena KIRAY
- Istanbul, TURKEY

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