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US 5,182,172 AGranted
Post-plating passivation treatment
AssigneeBausch & Lomb Incorporated
InventorJohn F. Tucker
Life of this patent
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Abstract
An improved method for inhibiting corrosion of precious metal plated objects is provided wherein a thin dichromate film coats the precious metal outer surface and fills the precious metal outer surface pores using either immersion or electrolytic methods employing passivation plating techniques. The method is useful in the manufacture of eyewear frames
Claims7
A method for reducing the corrosion of precious metal plated objects, the improvement comprising
- electroplating an object with a primary nickel-containing plate,
- electroplating the primary nickel-containing plate with the secondary nickel-palladium plate,
- electroplating the secondary nickel-palladium plate with a precious metal plate, and
- immersing the precious metal plated object in an aqueous solution containing about 1 gm/l to about 10 gm/l of ammonium dichromate at temperatures from about 20.degree. C. to about 50.degree. C. for a period of about 1 minutes to about 20 minutes.
1 more element
Dependencies are inferred from the claim text.