Mechanism of Friction and Wear in MoS2 and ZDDP/F-PTFE Greases under Spectrum Loading Conditions

Lubricants

Sujay D. Bagi²  Pranesh B. Aswath¹  Werner Oesterle² 

[1] id="af1-lubricants-03-00687">Materials Science and Engineering Department, University of Texas at Arlington, 501 West First Street, Rm. 231, Arlington, TX 76019, U

关键词: MoS₂;    ZDDP;    PTFE;    EDS;    lubricants;    four-ball tribometer;    wear;    friction;    grease;   

DOI  :  10.3390/lubricants3040687

来源: mdpi

【 摘 要 】

Two different greases formulated using MoS₂ and a combination of ZDDP and functionalized PTFE (F-PTFE) were examined under spectrum loading conditions where loads, frequency, and duration of the steps were treated as variables. Combination of ZDDP and F-PTFE were synergistic resulting in a significant reduction in the wear and friction under spectrum loading condition. Decreasing the time step during the ramp up and ramp down cycles resulted in larger wear for the grease containing MoS₂ particles in comparison to ZDDP/F-PTFE in grease. The tribofilm formed on the surface was analyzed using various characterization techniques like SEM, EDS, and Stereo Optical Microscopy. Tribofilms from MoS₂ additives had extensive amounts of abrasive and adhesive wear and showed the formation of MoS₂ on the surface on the other hand the tribofilms from ZDDP/F-PTFE had smaller amounts of severe wear and exhibited patchy tribofilms of Zn-phosphates as well as sulfides of Zn and Fe.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.