The Resistance of Porcelain Enamels to Surface Abrasion as Determined by the PEI Test

Porcelain enamels by virtue of their hardness have good abrasion resistance; yet this fact is not generally recognized for two reasons. In the first place, the term abrasion has many interpretations. According to Webster, to abrade can mean to rub, to scrape, to grind, or to wear away by friction. A porcelain enamel might withstand satisfactorily one of these types of abrasion but not another and thus be wrongfully adjudged. In the second place, due to the lack of a universally accepted standard method of test for abrasion, the comparative resistances of various types of materials cannot be readily ascertained. At present, one cannot turn to property tables and compare enamels with plastics, paints, metals, glass, and the like. About two years ago, a task force of Subcommittee III on Test Methods and Specifications of ASTM Committee C-22 on Porcelain Enamel was appointed to make a study of abrasion and to evaluate as one possible method the test for Resistance of Porcelain Enamels to Surface Abrasion, a standard of the Porcelain Enamel Institute.