Process for decreasing the porosity of gold
AssigneeBell Telephone Laboratories, Incorporated
InventorsDonald Eldridge Koontz, Peter Kenny Skurkiss
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Abstract
A process is described for making modified gold platings of low porosity. This process involves first putting down a gold layer and then passivating this layer using an electrochemical chromating procedure. This process permits use of much thinner gold layers than ordinarily used without the danger of corrosion of underlying base metal.
Claims15
A process for cathodically producing an article with at least one layer consisting essentially of at least 90 percent by weight of gold on a metallic surface consisting essentially of at least 50 weight percent of at least one metal selected from the group consisting of copper, nickel, tin, zinc and iron, said process comprising the step of passing current through an anode, aqueous solution and a cathode, with both cathode and anode at least partly immersed in the aqueous solution and in which said cathode includes the metallic surface with the layer CHARACTERIZED IN THAT the aqueous solution comprises chromium-containing ions so as to decrease the porosity of the layer as evidenced by a decreased number of spots in an electrographic porosity test using dimethylglyoxime as the indicator, said aqueous solution and conditions capable of depositing chromium chemically combined with oxygen on the unlayered metallic surface.
Dependencies are inferred from the claim text.