TY - JOUR

T1 - ZDDP containing tribofilms generated under sliding micro contact and bearing test rig conditions

AU - Pape, Florian

AU - Muhmann, Christian

AU - Pahl, David

AU - Lipinsky, Dieter

AU - Arlinghaus, Heinrich F.

AU - Poll, Gerhard

N1 - Funding Information: This work was sponsored in part by the DFG (German Research Foundation) within the research program “Influence of Stress States in Rolling Bearings on White Etching Cracks.”

PY - 2018/5/24

Y1 - 2018/5/24

N2 - For machine elements in relative motion (like bearings), lubrication ismandatory to prevent wear or premature fatigue and to reduce friction. Oils and greases typically contain additives to protect against wear and oxidation by building up a tribofilm with a thickness of a few ten nanometers. There is the suspicion that under some critical compositions and under specific test conditions, the resulting tribofilm can cause early bearing failure because of subsurface damages like white etching cracks (WECs). One component relevant for tribofilm formation is zinc dialkyldithiophosphate (ZDDP), which forms protective phosphate glass-based tribofilms. With the aim of detecting critical lubricant compositions and test parameters, experiments on an FE8 test rig were performed. To investigate the formation of tribofilms, tests were also executed using a modified Center for Tribology (CETR, now Bruker Corporation, Billerica, MA) Olympus HDI reliability spin-stand. This device was originally developed to investigate the head-to-disk interface of a hard disk drive (HDD). During the test cycles, the coefficient of friction was recorded. In order to determine the effect of the operation conditions, the microtribological properties of the boundary layers were analyzed. The boundary layers were investigated by means of nanoindentations and nanoscratches on the raceways. Additionally, time-of-flight-secondary ion mass spectrometry (ToF-SIMS) with depth profiling was used to analyze the adhering lubricant, as well as the composition of the boundary layers.

AB - For machine elements in relative motion (like bearings), lubrication ismandatory to prevent wear or premature fatigue and to reduce friction. Oils and greases typically contain additives to protect against wear and oxidation by building up a tribofilm with a thickness of a few ten nanometers. There is the suspicion that under some critical compositions and under specific test conditions, the resulting tribofilm can cause early bearing failure because of subsurface damages like white etching cracks (WECs). One component relevant for tribofilm formation is zinc dialkyldithiophosphate (ZDDP), which forms protective phosphate glass-based tribofilms. With the aim of detecting critical lubricant compositions and test parameters, experiments on an FE8 test rig were performed. To investigate the formation of tribofilms, tests were also executed using a modified Center for Tribology (CETR, now Bruker Corporation, Billerica, MA) Olympus HDI reliability spin-stand. This device was originally developed to investigate the head-to-disk interface of a hard disk drive (HDD). During the test cycles, the coefficient of friction was recorded. In order to determine the effect of the operation conditions, the microtribological properties of the boundary layers were analyzed. The boundary layers were investigated by means of nanoindentations and nanoscratches on the raceways. Additionally, time-of-flight-secondary ion mass spectrometry (ToF-SIMS) with depth profiling was used to analyze the adhering lubricant, as well as the composition of the boundary layers.

KW - Boundary layers

KW - Micro pin-on-disk

KW - Micro tribology

KW - Time-of-flight-secondary ion mass spectrometry

KW - Tribo-chemistry

KW - Zinc dialkyldithiophosphate tribofilm

UR - http://www.scopus.com/inward/record.url?scp=85047607282&partnerID=8YFLogxK

U2 - 10.1520/MPC20170067

DO - 10.1520/MPC20170067

M3 - Article

AN - SCOPUS:85047607282

VL - 7

JO - Materials Performance and Characterization

JF - Materials Performance and Characterization

IS - 3

ER -