Rose-colored gold alloy compositions with reversible hardness characteristics
View Patent ↗Improved 14-karat rose-colored gold alloy compositions include: about 58.5% gold; about 9.0-12.0% silver; about 0.0-0.2% zinc; about 0.3-0.4% cobalt; about 0.0-0.02% iridium; and about 29.0-33.0% copper. Improved 18-karat rose-colored gold alloy compositions include: about 75.2% gold; about 7.0% silver; about 0.0-0.2% zinc; about 0.3-0.4% cobalt; about 0.0-0.02% iridium; and about 17.0-17.5% copper. The hardness of these compositions are capable of being selectively changed between their respective annealed-hardness and age-hardness values. The color of these compositions is between about 5-7 CieLab a* color units and between about 17-21 CieLab b* color units.
1. A 14-karat rose-colored gold alloy composition, comprising:
about 58.5% gold;
about 9.0-12.0% silver;
about 0.0-0.2% zinc;
about 0.3-0.4% cobalt;
about 0.0-0.02% iridium;
about 29.0-33.0% copper;
wherein the hardness of said composition is capable of being selectively changed between its annealed-hardness value, obtained by heating the composition to about 1150° F. for about thirty minutes followed by a water quench, and its age-hardness value, obtained by heating said composition to about 600° F. for about one and one-half hours and thereafter being allowed to cool in a non-oxidizing atmosphere; and
wherein the color of said composition is between about 5-7 CieLab a* color units and between about 17-21 CieLab b* color units.
2. The composition as set forth in claim 1 wherein said annealed-hardness value is between about 160-185 VHN.
3. The composition as set forth in claim 1 wherein said age-hardness value is at least about 220 VHN.
4. A 14-karat rose-colored gold alloy composition, consisting essentially of:
about 58.5% gold;
about 9.0-12.0% silver;
about 0.0-0.2% zinc;
about 0.3-0.4% cobalt;
about 0.0-0.02% iridium;
about 29.0-33.0% copper;
wherein the hardness of said composition is capable of being selectively changed between its annealed-hardness value, obtained by heating the composition to about 1150° F. for about thirty minutes followed by a water quench, and its age-hardness value, obtained by heating said composition to about 600° F. for about one and one-half hours and thereafter being allowed to cool in a non-oxidizing atmosphere; and
wherein the color of said composition is between about 5-7 CieLab a* color units and between about 17-21 CieLab b* color units.
5. The composition as set forth in claim 4 wherein said amended-hardness value is between about 160-185 VEIN.
6. The composition as set forth in claim 4 wherein said age-hardness value is at least about 220 VHN.