ELECTROCHEMICAL EFFECTS ON FRICTION BETWEEN METAL-OXIDE SURFACES IN AQUEOUS-SOLUTIONS

The dependence on potential of the coefficient of friction between metal oxides in aqueous solutions has been investigated experimentally and modelled theoretically in terms of the effect of the electrostatic repulsion between surfaces, the charge on which was controlled by pH and/or electrode potential. The inter-surface pressure, resulting from the sum of van der Waals attraction and double-layer repulsion, was found to be important in determining the friction between metal/metal oxides in aqueous solutions when the applied pressure was <10 times the electrostatic repulsion pressure acting within the rubbing contact region.