Low-carat corrosion-resistant gold alloy with the skin of the alloy not being blacked upon casting
Abstract
Abstract A low-carat corrosion-resistant gold alloy which is not blacked in its skin surface color upon being cast is provided. The alloy is used as cast alloy for reparation of tooth crowns, as general decorative articles, or as contact alloy used in electrical apparatus. The alloy is composed essentially of gold, palladium and silver, with addition thereto of indium in place of copper contained in the conventional alloys, and necessary amounts of zinc or tin as deoxidant. Copper contents have been desired in view of improving the castability and mechanical strength of the alloy but the skin surface of the cast alloy may thereby be blacked to detract from aesthetic effects thus making it necessary to wash off the blacked oxide film by use of strong acid washing agents. The indium added in place of copper affords necessary mechanical properties to the alloy while providing aesthetically desirable silver to gray skin color and making the washing with strong acids unnecessary.
Inventors
- 👤 Masasuke Otsuka
- 👤 Hideyo Maniwa
- 👤 Shinya Nishina
Bibliographic Details
Claims Analysis
Total Claims: 2References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-10-24 | 1987-04-25 | 1987-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-24 | 1991-04-25 | 1991-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-24 | 1995-04-25 | 1995-10-25 | $7700.00 | Window Closed / Lapsed |