The electrode potential of freshly generated aluminium surfaces in lubricating oil

This paper describes the electrode potential of freshly generated aluminium surfaces measured using the guillotined electrode whilst it is submerged under lubricating oil. An initially low value of the bared metal surface is followed by a slow rise towards the steady state as repassivation proceeds. The presence of lauric acid, a surfactant, in the oil raises the potential of the initially bared surface, demonstrating its direct cathodic activity in the electrochemical reaction, an effect which decreases as repassivation progresses.