Coatings vitreous enamel

For both economic and technical reasons, the most effective way to impart color to a ceramic product is to apply a ceramic coating that contains the colorant. The most common coatings, gla2es and porcelain enamels, are vitreous in nature. Hence, most appHcations for ceramic colorants involve the coloring of a vitreous material. 

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. 

Porcelain enameling. This is the entire process of applying a fused vitreous enamel coating to a metal basis material. Usually this includes metal preparation and coating operations.3-7... 

Coating operations. This includes all of the operations associated with preparation and application of the vitreous coating. Usually this incorporates ball milling, slip transport, application of slip to the workpieces, cleaning and recovery of faulty parts, and firing (fusing) of the enamel coat. 

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. 

Application Weight. The weight of vitreous enamel coating applied, per unit area covered. 

Contrast Ratio (C80). A ratio related to the reflectance of a vitreous enamel coating and defined in ASTM C347 as The ratio of the reflectance of an enamel coating over black backing to its reflectance over a backing of reflectance 0.80 (80%). 

Granite Ware. This term has had various meanings wilhin the vitreous-enamel industry but the definition given in ASTM - C286 would restrict the meaning to a one-coat vitreous-enamelled article with a mottled pattern... 

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