Patents Examined by Ralph D. Flatter
  • Silver alloy compositions
    Patent number: 4973446
    Abstract: An improved sterling silver alloy composition, exhibiting the desirable properties of reduced fire scale, reduced porosity and reduced grain size, consists essentially of the following parts by weight: about 92.5% silver, about 0.5% copper, about 4.25% zinc, about 0.02% indium, about 0.48% tin, about 1.25% of a boron-copper alloy containing about 2% boron and about 98% copper, and about 1% of a silicon-copper alloy containing about 10% silicon and about 90% copper.
    Type: Grant
    Filed: June 7, 1990
    Date of Patent: November 27, 1990
    Assignee: United Precious Metal Refining Co., Inc.
    Inventors: Melvin Bernhard, James T. Sivertsen