| 摘要 |
<p>A firestain and tarnish-resistant alloy of silver, copper and germanium contains more than 94.5 wt% to 95.5 wt% Ag, from 1.0 to 1.5 wt% Ge and the remainder, apart from up to 0.5wt% incidental ingredients (if any), impurities and boron in an amount effective to bring about grain refinement, copper, the weight ratio of Cu to Ge being from 2.5:1 to less than 3:1. The boron may be added as a copper-boron alloy, boron hydride, sodium borohydride or borane.</p> |
