John, S. and Pushpavanam, M. and Shenoi, B.A. (1985) Studies on post-treatment of gold plated silver. Bulletin of Electrochemistry , 01 (02). pp. 129-130. ISSN 0256-1654

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Silver articles like jewellery, silverwares, cosmetic containers, novelties, presentation items etc. are usually plated with gold in very thin deposits to give good appearance and to protect silver from tarnishing. A verythin deposit of gold is often porous, and the silver tarnishes through the pores. This tarnishing will spread laterally over the gold and the whole component will turn black. This is often thought to indicate that the gold has tarnished, but this is not true. Thick layers of gold is useful in preventing tarnish films. However, it is very expensive. Other methods of reducing the tendency of silver to tarnish are to coat the surface with a special lacquer, grease, oil or wax or to apply special oxide or chromate films. Electrolytic treatment of goldplated silver in an electrolyte containing 40 g/l potassium chromate, 40 g/l potassium carbonate at pH 8.8 at a cathodic current density of 2.5 A/dm2'for 1-3 minutes significantly improves the tarnish resistance as revealed by the accelerated stain proofing test

Item Type: Article
Subjects: Industrial Metal Finishing
Depositing User: ttbdu cecri
Date Deposited: 21 Mar 2012 02:25
Last Modified: 21 Mar 2012 02:25

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