Some Examples of the Functional Use of Porcelain Enamel and Ceramic Coatings for Steel

Porcelain enamels are fundamentally very superior protective coatings which combine with their protective characteristics a highly decorative finish. The porcelain enameling art, that is, the application of glass to metals for decorative effect, has been practiced for several thousand years. The industrial application of porcelain enamels, taking advantage of their protective characteristics, is an achievement of recent origin begun during the last of the nineteenth century and approaching its modern status only during the past thirty years. It is no wonder, therefore, that those not acquainted with the material tend to consider only the decorative properties of the product and largely ignore its characteristics as an engineering material. The general public is, therefore, prone to accept the application of porcelain enamel coatings to sanitary ware and home appliances as an advance in the decorative improvement of the kitchen and the bathroom. They do not realize that these coatings were chosen, in fact often specially developed for the specific end uses, to provide protective qualities enabling the appliances and sanitary ware to give them long-lasting, satisfactory service. Similarly, in architectural applications the public does not usually recognize that this finish provides not only a highly decorative building but also a very economical structure that can be readily erected and maintained for years with a minimum expenditure. In all of these cases, porcelain enamel has been chosen and applied chiefly because of its quality as a protective finish. The highly decorative aspects—valuable and not to be overlooked—are somewhat incidental to the utilitarian properties of the material. It is the purpose of this Symposium to consider the merits of porcelain enamels and ceramic coatings fundamentally as engineering materials. This paper is concerned with a general correlation between the general physical properties of porcelain enamels and ceramic coatings and past and present uses of the coatings as engineering materials.