Limitation induced by electrical charges effects on micromechanisms

Electrical charges generation occurring during contact, friction or fracture of insulating materials (ceramics, polymers) has been identified for a long time. But the contribution of these electrical charges to the friction and wear behaviour is usually neglected in the energetical balance. Based on published results and on our own experimental results on the ability of the insulating material on trapping charges, we show in this study that the interaction energy during friction depends markedly on these trapped charges which induce moreover long distance effects. Consequently, on the particular case of microdevices for which the surface area to volume ratio is large and the external pressure is low, such effects can act markedly upon both friction coefficient evolution and wear resistance by storage and release of polarisation energy in the whole tribosystem.