| 摘要 |
<p>- CANADA A gold-cobalt alloy is electroplated on a substrate by passing an electric current between an anode and the substrate in a bath comprising an aqueous solution of: (a) gold potassium cyanide (b) nitrilotriacetic acid and (c) a cobalt salt in amount to provide 0.1 to 7.0 gpl of cobalt in the solution, the bath being at a pH of 3.5 to 6.0. The preferred bath comprises an aqueous solution containing: (a) 1.0 to 4.0 troy ounces per U.S. gallon (8.2 to 32.8 gpl) of gold, added as K Au (CN)2. (b) 3 to 100 gpl of nitrilotriacetic acid and (c) 0.1 to 7.0 gpl of cobalt added as cobalt sulphate, halide, nitrate or carbonate, the bath being at a pH of 3.5 to 6.0 and a temperature of 80 to 150 F (27 to 66.degree.C) and the current passing at a density of between 1 and 100 ASF (0.1 to 11 ASD) at the cathode. The solution may also contain one or more of tripotassium citrate, dipotassium hydrogen phosphate and potassium dihydrogen phosphate as electrolytes.</p> |
