Gold alloys of exceptional yellow color and reversible hardness
US5180551A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 30, 1991 |
| Grant date | Jan 19, 1993 |
| Priority date | — |
| Expiry date | Oct 30, 2011 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC22C5/02
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A unique hardenable gold based alloy, especially a 14 karat gold alloy containing gold, silver, copper, zinc, cobalt and an alternative alloy additionally containing iridium. The alloy has a fine grained structure, a lower hardness in the soft condition, a nice yellow color and a capability to be hardened to an exceptional hardness value. The alloy contains approximately 58.3% gold (Au), between about 10% to about 14% silver (Ag), between about 2.5% to about 3.0% zinc (Zn), between about 0.2% to about 1.0% cobalt (Co) and the balance of the alloy being copper (Cu) with the special provision that the ratio of the weight percent amounts of copper to, the sum of the silver and two (2) times the zinc amount, [Cu/(Ag+2Zn)], has a value of between about 1.3 to about 2.5. The copper to silver weight percent ratio [Cu/Ag] of between about 2.0 to about 3.8, in combination with the ratio of copper to, silver+2.times.zinc, [Cu/(Ag+2Zn)] results in a gold alloy with a heretofor unachievable combination of a most desirable yellow color and an exceptional degree of reversible hardness. The alloy may also contain a weight percent amount of between about 0.003 to about 0.03 iridium (Ir) which resu…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.