| 摘要 |
1,177,373. Electro-deposition of gold or gold alloy. ENGELHARD MINERALS & CHEMICALS CORP. Jan.19, 1967[Jan.21, 1966], No.3000/67. Heading C7B. An electrolyte solution for use in the electrodeposition of gold or gold alloy comprises 1-50 g. alkali metal gold cyanide 10-200 g. alkali metal or ammonium pyrophosphate 20-100 g. superphosphoric acid 0À005-0À5 g. in total of at least one of the base metals Co, Ni, Cd and Zn, per litre of solution, the solution having a pH in the range from 3À5 to 4À5. Superphosphoric acid is defined as a mixture containing orthophosphoric acid and pyrophosphoric acid, with or without one or more of the other polyphosphoric acids, the mixture containing an equivalent of from 72 to 85% by weight of P 2 0 5 .. The base metal(s) may be added as a polyphosphate (e.g. pyrophosphate), orthophosphate or sulphate. The solution may also contain 5 to 20 g. /1. of dihydrogen ammonium phosphate. Examples are of electro-plating brass strip using electrolytes wherein the superphosphoric acid contains triphosphoric acid. |
