Tarnish-resistant precious-metal alloys for dentistry

US4909985A · kind A · utility

Assignee

• Degussa AG · DE

Inventors

• Rudolf Kropp · Schifferstadt, DE
• Wolfgang Kuerten · Birkenfeld, DE

Key dates

• Filing date: Jun 2, 1989
• Grant date: Mar 20, 1990
• Expiry date: Jun 2, 2009

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C22C5/00
• WIPO field: Pharmaceuticals
• WIPO sector: Chemistry

Abstract

Economical, tarnish-resistant precious-metal alloys for dentistry consisting essentially of 36 to 39% silver, 28 to 32.5% gold, 17 to 19.5% palladium, 0 to 0.1% iridium, 9.5 to 10.5% copper, 0.5 to 3% indium and 0.5 to 2.5% zinc, whereby the sum of the indium and zinc contents does not exceed a maximum of 4%.