| The anti-tarnish and burning resistance properties of 925Ag alloy are investigated by manipulating trace indium and tin contents, makes progress in solving the problem of 925Ag alloy tarnishing caused by sulphurization and oxidation. The results indicates that 0.375 wt% of In enhances the anti-sulphurization and anti-perspiration properties while extremely low content of In affectes those two properties adversely, and the effects of solely addition of Sn on those two properties are not obvious. Trace In and Sn’s mechanisms and effects of protecting Zn within the 925Ag alloy is intricate. When melting time is short, In protects Zn more effectively than Sn, though Sn prolongs the protection time for Zn. When the content of In and Sn drop to a certain level, burning of Zn will be accelerated. Zn plays an important role in improving the anti-discoloration of silver alloy, so the content of In, Sn, Zn were determined according to re-melting times, melting duration time and service environment of the silver alloy to achieve the desired results. |
