The influence of lubricants on white etching areas formation in DLC-coated bearing steel under severe boundary lubrication

Abstract

White etching areas (WEAs) and white etching cracks (WECs) are the catastrophic premature failure modes associated with wind turbine gearbox bearings. Several drivers, including lubricant chemistry, influence the evolution of WEAs and WECs. This study investigated the performance of base oils with various lubricant chemistry against microstructural decay in DLC-coated AISI 52100 bearing steel. Tests were performed in sliding-dynamic loading conditions under severe boundary lubrication. The effect of base oils against WEAs formation in DLC-coated steel is explored by analysing the condition of oils, wear behaviour, and subsurface microstructural change. The study outcomes revealed that the selection of base oils plays a vital role against the WEAs formation in DLC-coated bearing steel subsurface.