Coins coated with nickel, copper and nickel and process for making such coins
US5151167A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 4, 1991 |
| Grant date | Sep 29, 1992 |
| Priority date | — |
| Expiry date | Dec 4, 2011 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC25D5/627
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
This invention overcomes problems such as pinholes and blisters in making plated coin blanks and similar articles. A ferrous metal blank is electroplated with a strike of nickel, following which a coating of copper is applied at an initial low current density followed by full current density to minimize bridging. The low current density may be about 1/6 to 1/4 of the full current density. Preferably an outer layer of nickel is applied, also at an initial low current density, followed by full current density. Annealing before or after application of the final layer of nickel is advisable. This invention also relates to the resulting coin blank and coins.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.