Coins coated with nickel, copper and nickel
US5139886A · kind A · utility
9Cited by
4References
8Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jun 28, 1991 |
| Grant date | Aug 18, 1992 |
| Priority date | — |
| Expiry date | Jun 28, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/12937
- 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. 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.