Some Adhesion Phenomena Involving Glasses, Metals and Fused Salts and their Interpretation

JSGT 1948 V32 T264-T280

 Many salts or glasses adhere tenaciously to the walls of platinum crucibles or porcelain containers in which they are melted. It has been found that minor additions of certain substances to fused salts and glasses prevent this adhesion. Sodium or potassium chloride fused in a porcelain or in a platinum crucible adheres firmly. So does a melt of sodium or potassium iodide. Nevertheless, a few per cent. of an iodide added to an alkali chloride melt completely prevents adhesion. Addition of lead chloride to an alkali halide exerts a similar effect. The same observations were made with borate, silicate and phosphate glasses. Experiments were performed which eliminate differences in the thermal expansion as a possible cause of adhesion and non-adhesion. An explanation is presented, based on the formation of capillary-active groups in the surface layer of the molten salts and glasses.

E. C. Marboe, W. D. Smiley & W. A. Weyl