raw plates in larger quantities and more economically. Electroplating In electroplating, the item to be coated is placed into a container containing a solution of one or more tin salts. The item is connected to an electrical circuit, forming the cathode (negative) of the circuit while an electrode typically of the same metal to be plated forms the anode (positive). When an electric current is passed through the circuit, metal ions in the solution are attracted to the item. To produce a smooth, shiny surface, the electroplated sheet is then briefly heated above the melting point of tin. Most of the tin-plated steel made today is then further electroplated with a very thin layer of chromium to prevent dulling of the surface from oxidation of the tin. Alternatives Terne-plate is a similar product to tinplate, but the bath is not of tin, but of tin and lead mixed, the latter metal constituting from 7.59% of the whole. The name derives from "terne", meaning dull or tarnish. Terne-plates began to be produced in England about the middle of the 19th century, and became widely employed in the United States for roofing purposes. Other applications included fuel tanks and gas meters. The last Terne-plate mill in Brockmoor, West Midlands in the UK was closed in 2006. For many purposes, tinplate has been replaced by galvanised (zinc-coated) vessels - though not for cooking, as zinc can be toxic. Zinc protects iron electrolytically, that is, the zinc will oxidise and turn to a white powder to preserve the iron, whereas tin will only protect the iron if the tin-surface remains unbroken, as it electrolytically cannibalises unprotected iron to preserve itself. See also Blackplate Kalai (process), a form of tinning practiced in India Plating for other processes for plating metals Sherardizing Tinsmith Tinware Black oxide References Bibliography Further reading F. W. Gibbs, 'The rise of the tinplate industry' Annals of Science 6 (1950), 390ff; 7(1) (1951), 25ff; 43ff; 113ff. P. Jenkins, 'Twenty by Fourteen': a history of the south Wales tinplate industry 1700-1961 (Gomer, Llandysul, Dyfed 1995). D.A. Irwin, 'Did late nineteenth century U.S. tariffs promote infant industries? Evidence from the tinplate industry' (NBER working paper 6835 1998) Coatings Industrial processes Metal plating Metallurgical processes Steelmaking Thin film deposition Tin