Influence of environmental friendly multiphase lubricants on the friction and transfer layer formation during sliding against textured surfaces

摘要

Both surface texture and multiphase lubricants (additives in base oil) influence the friction and wear performance during sliding. However, the synergy of their interaction is still unknown. In the present investigation, an effort is made to understand the influence of environmental friendly multiphase lubricants on the friction and transfer layer formation during sliding against various surface textures. In this study, unidirectional surface textures were created and sliding tests were conducted against various grinding angles of the unidirectional texture. The sliding tests were conducted in multiphase lubricants consisting of canola oil (biolubricant) and nano-additives (graphene) at various concentrations. The results showed that the coefficient of friction (COF) and transfer layer formation was influenced by the grinding angle. However, it was found that this influence can be minimized by using an optimum concentration of graphene in canola oil. A minimum COF of 0.05 +/- 0.01 could be achieved for various grinding angles by utilizing a specific concentration of graphene. It was found that a high concentration of Gr (3 wt%) was required when sliding at 0 degrees and a low concentration of Gr (1 wt%) was required when sliding at 45 degrees to achieve the minimum COF. This was attributed to the variations in asperity and Gr additive interaction when sliding at different grinding angles. The present study details the observed friction and transfer layer formation results and analyzes the mechanism of multiphase lubrication during sliding at various grinding angles. An asperity interaction model for sliding against various grinding angles and in a multiphase lubricant with varying additive concentrations has also been presented. (C) 2018 Elsevier Ltd. All rights reserved.