An Indirect Electric Field Effect on the Friction of Boundary-Lubricated Contacts

To achieve significant friction variations by means of an externally applied voltage, it is found to be more effective to impose an electric field on the area surrounding a tribopair rather than directly through the contact. Using a new applied electric field setup, the friction behaviour of ceramic-metal tribopairs, lubricated with an aqueous emulsion, is investigated. The potential affects the surface characteristics during the instant that the surface is out of rubbing contact. Consequently, the nominal frictional behaviour differs from that with no potential effect. The unexcited, excited, and post-excited friction results for six different ceramic-metal couples using a pin-on-disc tester are presented, and their characteristics are summarised.