Electrolytic bath and process for the deposition of gold alloy coatings
AssigneeDegussa AG
InventorsWolfgang Zilske, Werner Kuhn
Life of this patent
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Abstract
In the electro industry, there are needed acid gold alloy baths which give glossy, ductile coatings, operate at high current densities, and contain little non-metallic impurities. This is attained by a bath based on potassium cyanoaurate (III) and an acid whereby the bath contains at least one of the alloying metals cobalt, nickel, indium, tin, zinc, or cadmium in the form of a water soluble salt, together with an amine, an aminocarboxylic acid, or a phosphonic acid and has a pH of below 3.
Claims20
A gold bath suitable for the deposition of high gloss and ductile gold alloy coatings consisting of either (1) water, potassium cyanoaurate (III), at least one alloying element selected from the group consisting of cobalt, nickel, indium, zinc, and cadmium in the form of a water soluble salt together with a hydrocarbyl amine, an aminocarboxylic acid, or a phosphonic acid which forms a complex with the alloying element and 20-200 g/l of sulfuric acid, phosphoric acid, citric acid or a mixture thereof, or (2) the gold bath (1) together with potassium dihydrogen phosphate, potassium hydrogen sulfate or potassium citrate, said bath having a pH of less than 3.
Dependencies are inferred from the claim text.