Enhancement effect of nanoparticles on the sliding wear of short fiber-reinforced polymer composites: A critical discussion of wear mechanisms

Short fiber-reinforced polymers (SFRPs) form an important class of tribo-materials owing to their high specific strength, good load-carrying capacity and rapid, low-cost processibility. Nevertheless, further developments are still under way to tailor their properties for more extreme loading conditions and to explore new fields of application for these materials. Recently, nano-sized inorganic particles have come under consideration. It was found that the addition of a small percentage of rigid nanoparticles to SFRPs may significantly improve their wear resistance, especially under high pv (the product of p (pressure) and v (velocity)) conditions. However, the detailed mechanisms of such improvement have not been fully understood yet. The objective of this study is to achieve an in-depth understanding of the role of the nanoparticles in modifying the sliding wear behavior of SFRPs. In particular, the effects of nanoparticles on contact mechanics and wear behavior of the transfer film were investigated. It was found that the additional nanoparticles do not directly contribute to the formation of a high performance transfer film. However, the presence of nanoparticles in the contact region can effectively reduce the adhesion between the transfer film and the polymeric specimen, resulting in a lower coefficient of friction. In particular, the rolling behavior of nanoparticles can significantly enhance the tribological performance of SFRPs especially under extreme sliding conditions. (C) 2010 Elsevier Ltd. All rights reserved.