Effects of external electric fields on frictional behaviors of three kindsof ceramic/metal rubbing couples

In this paper, effects of external electric fields on frictional behaviors of Al2O3/brass, Al2O3/stainless steel and Al2O3/carbon steel couples under boundary lubricating conditions were studied on a self-made plate/plate typ e tribotester. Emulsion of 1 wt% zinc stearate dispersed into deionized wat er was used as lubricant in the experiments. The experiment results have sh own that external electric fields affect the friction coefficient and its f luctuation of each rubbing couple substantially. The three couples showed d ifferent rates of change in. friction coefficient and different tendency of change as the field was turned on and off during the rubbing process. Resu lts acquired from experiments carried out in a wide range of external volta ge, from 0 to 110 V, indicating that friction coefficient of Al2O3/brass co uple increases monotonously with the intensity of the external electric fie ld, although no linear relationship was found between them. (C) 1999 Elsevi er Science Ltd. All rights reserved.