Material Transfer in Monomolecular Layers of a Boundary Lubricant

Abstract

Bailey and Courtney-Pratt¹ have studied the shearing of monomolecular layers of calcium stearate between flat mica sheets. They concluded that this shearing in the boundary lubricant film, which may afford almost perfect protection against wear, still contributes significantly to sliding friction. The processes which occur in the contact of such atomically flat surfaces protected by boundary films are therefore of some interest. It has been shown that mica surfaces brought into contact interchange the exchangeable potassium ions on their surfaces (preceding communication). This observation seems to support the postulate that the adhesive force between mica surfaces is ionic in nature². Rideal and Tadayon³ observed transfer of stearic acid from monolayers deposited on mica to other mica surfaces, but the major portion of their work seems to have been concerned with surface diffusion processes rather than true contact transfer.