The Influence of Electrochemical Potentials on the Friction and Wear of Iron and Iron Oxides in Aqueous Systems

This paper examines the influence of electrochemical potentials on the friction and wear of iron/iron and iron oxide/alumina oxide rubbing contacts, lubricated with aqueous fluids. The chemical nature of surface films on metals under electrode potential control has been investigated using simultaneous voltammetry, impedance spectroscopy and Fourier transform infrared (FTIR) microspectroscopy. This approach has enabled the friction and wear behavior of rubbing contacts with well-defined and controlled surface compositions to be investigated as a function of electrode potential. It has been shown that electrochemical potentials influence friction coefficient in two separate ways, i.e., by modifying the effective inter-surface normal force via electrochemical double layer effects and by controlling the surface chemistry and then the shear strengths of the films present on the rubbing surfaces.