ROLE OF TRIBOELECTRIFICATION IN THE FRICTION OF SLIDING SURFACES

. ABSTRACT The present work aims to decrease the friction coefficient displayed by the sliding polymeric composites on steel surface by filling the polymeric composites by conductive materials in order to decrease the resultant electrostatic charge (ESC) that increased the attraction between the two sliding surfaces. Experiments have been carried out to investigate the influence of filling the polymeric composites consisting of PMMA and PE by electrically conductive materials such as copper, aluminum, carbon fibers and carbon nanotubes on the friction coefficient when slid on bearing steel sphere at dry sliding conditions. It was found that PE gained negative charge during friction against steel that at the same time gained positive charge, while PMMA acquired positive charge when slid on steel that got negative one. The resultant charge gained by composites surface would be minimum. The positive and negative charges conducted into steel surface became neutralized if the two different charges are equal. The addition of sand particles into the composites aimed to enhance the wear resistance but it increased the friction coefficient. To overcome that behavior, different conductive materials were added, where carbon fibers experienced the best performance by reducing friction coefficient through decreasing ESC by conducting the different charges to each other.