The tribology behaviors of the brass/silicon dioxide sliding couple under controlled electrode potential were investigated on self-made friction tester. The results showed that the electrode potential of the brass had a dramatic influence on the tribological behaviors of the frictional couple. An interesting phenomenon is that during certain electrode potential range the friction coefficient of the couple was controllable. The SEM morphologies of worn surfaces of the brass also showed different wear mode under different electrode potentials. (C) 2002 Elsevier Science B.V. All rights reserved.