TY - JOUR

T1 - Nano- and Micro-Tribological Investigations of Boundary Layers on Axial Bearing Washers Tested under WEC Critical Conditions

AU - Pape, Florian

N1 - Funding Information: This work was sponsored in part by the DFG within the research programs “Influence of stress states in rolling bearings on White Etching Cracks” and “AWEARNESS Anti-Wear-Effectiveness of Additives using a Rabinowicz and Eyring based Simulation Scheme” (No. 461911253). Funding Information: The author gratefully acknowledges the discussions and support of this project by Gerhard Poll and his team from the Institute of Machine Design and Tribology, Leibniz University Hanover, Germany. The ToF-SIMS measurements were performed in cooperation with the AG Arlinghaus of the Institute of Physics at the University of Münster, Germany. For the support, the author gratefully acknowledges Dieter Lipinsky, Christian Muhmann, and Dennis Mallach. For support in terms of nanomechanical characterization, the author gratefully acknowledges the support of Behrens of the Institute of Forming Technology and Machines, Leibniz University Hanover, Germany, and the discussions with Tim Matthias and Norman Heimes.

PY - 2022/8

Y1 - 2022/8

N2 - The formation of boundary layers on bearing surfaces due to the operational conditions has a significant influence on bearing lifetimes and frictional properties. Zinc dialkyldithiophosphate is an anti-wear additive widely used in oil and grease formulations that forms beneficial surface boundary layers. Under certain circumstances, this additive can cause early bearing failure due to white etching cracks (WEC) formation. By influencing chemical reactions and diffusion processes, the boundary films are suspected to be a reason for the emergence of WECs. The properties of these layers under WEC critical and uncritical conditions are of interest. To gain knowledge of these layers, nano- and micro-tribological tests were performed. One possibility is to measure the hardness by nanoindentation and scratching on and into the layers by nano scratch tests. Another way is to perform local resolved micro-pin-on-disk tests. Additionally, ToF-SIMS (Time-of-Flight Secondary Ion Mass Spectrometry) was performed on the bearing surfaces to conclude the chemical compositions of the boundary layers. In the focus was, if the measured properties of the layers can be correlated to the bearing’s early failures due to WEC, frictional properties of the whole system, and the wear on the surfaces.

AB - The formation of boundary layers on bearing surfaces due to the operational conditions has a significant influence on bearing lifetimes and frictional properties. Zinc dialkyldithiophosphate is an anti-wear additive widely used in oil and grease formulations that forms beneficial surface boundary layers. Under certain circumstances, this additive can cause early bearing failure due to white etching cracks (WEC) formation. By influencing chemical reactions and diffusion processes, the boundary films are suspected to be a reason for the emergence of WECs. The properties of these layers under WEC critical and uncritical conditions are of interest. To gain knowledge of these layers, nano- and micro-tribological tests were performed. One possibility is to measure the hardness by nanoindentation and scratching on and into the layers by nano scratch tests. Another way is to perform local resolved micro-pin-on-disk tests. Additionally, ToF-SIMS (Time-of-Flight Secondary Ion Mass Spectrometry) was performed on the bearing surfaces to conclude the chemical compositions of the boundary layers. In the focus was, if the measured properties of the layers can be correlated to the bearing’s early failures due to WEC, frictional properties of the whole system, and the wear on the surfaces.

KW - boundary layers

KW - mechanochemistry

KW - micro pin-on-disk

KW - micro tribology

KW - nano scratch

KW - ToF-SIMS

KW - tribo-chemistry

UR - http://www.scopus.com/inward/record.url?scp=85137367541&partnerID=8YFLogxK

U2 - 10.3390/lubricants10080198

DO - 10.3390/lubricants10080198

M3 - Article

AN - SCOPUS:85137367541

VL - 10

JO - Lubricants

JF - Lubricants

SN - 2075-4442

IS - 8

M1 - 198

ER -