Vitreous enamel coatings purpose

A vitreous enamel coating is, as the name implies, a coating of a glassy substance which has been fused onto the basis metal to give a tightly adherent hard finish resistant to many abrasive and corrosive materials. The purpose of modern vitreous enamels is twofold, i.e. to confer corrosion protection to the metal substrate and at the same time to provide permanent colour, gloss and other aesthetic values. 

PROTECTIVE COATING. A film or thin layer of metal glass of paint applied to a substrate primarily to inhibit corrosion, and secondarily for decorative purposes, Metals such as nickel, chromium, copper, and tin are electrodeposited on the base metal paints may be sprayed or brushed on. Vitreous enamel coatings are also used these require baking. Zinc coating are applied by continuous bath process in which a strip of ferrous metal is passed through molten zinc. 

The CTi02)x films are also applied to glass or vitreous enamel for decorative purposes. Thin films enhance brilliance thicker films impart a silver-gray luster. Milk glass can be produced by mixing the titanate with a low melting enamel, which sinters when the coating is baked (424). 

Cobalt Sulphate, C0SO4.7H2O. A soluble cobalt compound used for the same purpose as cobalt chloride (q.v.). It is also sometimes used in vitreous enamels for mottling single-coat grey-coloured ware. 

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