Controlling the phase composition and properties of a high silica enamel

Abstract

For some years past the development and use of glass-crystalline enamels for alloy steels has been becoming widespread; among them are also the high silica coatings. However, in developing a coating, the crystallization of which occurs during the deposition of the enamel, it is difficult to insure a continuous coating. This is explained by the fact that with the beginning of crystallization the viscosity (structural) of the melt increases and uniform pouring (spreading) of the enamel after degasification becomes difficult as a result of which the cladding remains porous. To obtain a continuous nonporous coating it is desirable that the intensity of crystallization be a minimum up to complete degasification and uniform pouring of the melt. Therefore the effect of additions during the milling on the coating quality, deposition, the crystallizing ability, and the phase composition of the glass-crystalline high silica enamel 53A was studied. Clay and bentonite (separately and together), and also oxides of chromium, zinc, tin, titanium, zirconium, aluminum, and copper served as additions (Table i).