Analysis of the relationship between roughness parameters of wear surface and tribology performance of 5CB liquid crystal

The aim of this work was to investigate the relationship between roughness parameters of wear surface and lubricating performance of 4-Cyano-4 '-pentylbiphenyl (5CB) liquid crystal. After running-in with acetylacetone (Hacac), lubricating with 5CB realizes a significant friction reduction and generates a groove-structured wear surface with larger Sku, more negative Ssk, smaller Str, and a higher Svk/Spk, which are in good agreement with the roughness parameters that achieving lower friction. Chemical reactions in the running-in process with Hacac changes the morphology of wear debris and decreases its particle size and Si content, which are believed to be reasons for the formation of the groove structured wear surface. Damaging the groove-structured wear surface, by introducing a process of washing up wear surfaces or lubricating with ethanol briefly between running-in with Hacac and lubricating with 5CB, changes roughness parameters of wear surface and induces higher friction coefficient. We hope this study will provide a new perspective to understand the effect of roughness parameters on tribological performance, and to provide references for surface designing.(c) 2022 Elsevier B.V. All rights reserved.