Sliding energy of textured surfaces via pendular tests

Abstract

PurposeSurface texturing can improve the tribological performance of contacting sliding surfaces under different contact and lubrication conditions, which has been proved both numerically and experimentally. This study aims to suggest a new methodology to evaluate the tribological behavior of textured surfaces using an adapted pendular scratch tester.Design/methodology/approachA Charpy-type tester was adapted to meet conditions that are relevant for sliding surfaces. The test rig was used to evaluate low carbon steel textured surfaces produced via maskless electrochemical texturing. The textures were composed of 100 pockets with an average diameter of 200 µm of and variable average depths (1.5, 3.5 and 7 µm). The tests were performed under dry and lubricated conditions for smooth and textured surfaces. The lubricated tests simulated a starved condition by applying a drop of lubricant.FindingsFor starved lubrication, surface texturing reduced the sliding energy when compared with smooth surfaces. This was attributed to the pocket’s ability to provide an additional supply of lubricant, as well as a reduced amount of plastic deformation around the pockets during sliding of the indenter. However, under dry sliding conditions, no significant effect of surface texturing was detected.Originality/valueA new evaluation methodology was proposed, using single-pass pendular sliding of a spherical indenter to measures the energy absorbed during sliding, which was referred to as sliding energy. The measurements are repeatable and can detect sliding energy differences between smooth and textured surfaces.