Effect of an electric field on friction of silicone rubber against steel in the motor base oil's environment

The paper presents the experimental results of research on the effect of an external DC electric field on the coefficient of friction of silicone rubber (elastomer) during its rubbing against a steel surface in the „pin-on-disc” experimental set-up. In the tests there were used silicone rubber samples, the pure PAG and PAO synthetic base oils and their blends with an antiwear (ZDDP) additive. The coefficient of friction μ was determined under conditions with and without an external DC electric field. A DC electric field was generated between a silicone rubber sample and a rotating steel disc (a friction pair). A sample holder was electrically isolated from other metal parts of a tribometer and was connected to one of the poles of a DC power supply, while the other pole was connected by means of the carbon brushes to a rotating steel disc. The experimental results show that the external DC electric field established between the rotating steel disc and a silicone rubber sample causes the coefficient of friction to decrease. It was also found that the coefficient of friction μ depends on the steel disc's angular velocity n, the contact pressure p, and the type of base oil and its blends with the additive used.