18-karat green gold alloy compositions
US6406568B1 · kind B1 · utility
1Cited by
1References
7Claims
0Family size
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Key dates
| Filing date | Aug 22, 2001 |
| Grant date | Jun 18, 2002 |
| Priority date | — |
| Expiry date | Aug 22, 2021 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC22F1/14
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
An improved 18-karat green gold alloy composition comprises about 75.0% gold; about 6.0-7.0% silver; about 9.0-11.7% copper; and about 6.5-9.0% zinc. The improved alloys are capable of being age-hardened to a hardness of about 240 VHN by being heated to about 550° F. for about one hour, and thereafter being permitted to cool in air. The hard-nesses of the alloys are reversible between their aged-hardness and annealed-hardness values. The color of said composition is between about −1.5 to about −3.0 CieLab a* color units, and between about 19 to about 26 CieLab b* color units.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.