skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Plasma-Functionalized Polytetrafluoroethylene Nanoparticles for Improved Wear in Lubricated Contact

Abstract

Plasma-functionalized polytetrafluoroethylene (PTFE) nanoparticles were employed to evaluate their utility in improving the lubrication property of a group III mineral oil with a significantly low amount of zinc dialkyl dithiophosphate (ZDDP). The particles were coated with two consecutive films; the initial coating contained silica to enhance amorphous glassy tribofilm formation, followed by a methacrylate film to protect the silica coating and enhance dispersibility in the oil. The functionalized nanoparticles were evaluated for their tribological performance using a high-frequency reciprocating rig, in a cylinder-on-flat configuration. The oil formulations containing ZDDP (350 ppm phosphorus level) and the functionalized nanoparticles resulted in dramatic reductions in the friction coefficient and overall wear compared to the samples containing nonfunctionalized PTFE nanoparticles, ZDDP (350 ppm P), and samples devoid of nanoparticles but containing ZDDP with a 700 ppm P treat rate. XPS and XANES spectroscopy were employed to characterize the tribological films formed on the test samples. The samples with functionalized particles and ZDDP clearly exhibited tribofilms with Si- and F-doped polyphosphates of Zn coupled with the presence of ZnS at the metal-tribofilm interface. On the other hand, oils without the functionalized nanoparticles have oxides of Fe and to a lesser extent short-chain phosphates of Zn.more » The overall results suggest that the synergism between plasma-coated PTFE nanoparticles and ZDDP contributed to the development of protective tribofilms even at reduced amount of phosphorus in the oil. This new method of employing nanoparticles to deliver novel antifriction and antiwear chemistries at the tribological interfaces stands out as a promising approach to further reduce P levels in oils without compromising friction and wear performance.« less

Authors:
 [1];  [2];  [3]; ORCiD logo [1]
  1. Materials Science and Engineering, University of Texas at Arlington, P.O. Box 19031, Arlington, Texas 76019, United States
  2. Chemistry and Biochemistry, University of Texas at Arlington, P.O. Box 19065, Arlington, Texas 76019, United States
  3. Argonne National Lab, Argonne, Illinois 60439, United States
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE) - Office of Vehicle Technology
OSTI Identifier:
1416002
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: ACS Applied Materials and Interfaces; Journal Volume: 9; Journal Issue: 30
Country of Publication:
United States
Language:
English
Subject:
plasma functionalization; PTFE; ZDDP tribofilms; synergistic; tribological evaluation

Citation Formats

Sharma, Vinay, Timmons, Richard, Erdemir, Ali, and Aswath, Pranesh B. Plasma-Functionalized Polytetrafluoroethylene Nanoparticles for Improved Wear in Lubricated Contact. United States: N. p., 2017. Web. doi:10.1021/acsami.7b06453.
Sharma, Vinay, Timmons, Richard, Erdemir, Ali, & Aswath, Pranesh B. Plasma-Functionalized Polytetrafluoroethylene Nanoparticles for Improved Wear in Lubricated Contact. United States. doi:10.1021/acsami.7b06453.
Sharma, Vinay, Timmons, Richard, Erdemir, Ali, and Aswath, Pranesh B. Thu . "Plasma-Functionalized Polytetrafluoroethylene Nanoparticles for Improved Wear in Lubricated Contact". United States. doi:10.1021/acsami.7b06453.
@article{osti_1416002,
title = {Plasma-Functionalized Polytetrafluoroethylene Nanoparticles for Improved Wear in Lubricated Contact},
author = {Sharma, Vinay and Timmons, Richard and Erdemir, Ali and Aswath, Pranesh B.},
abstractNote = {Plasma-functionalized polytetrafluoroethylene (PTFE) nanoparticles were employed to evaluate their utility in improving the lubrication property of a group III mineral oil with a significantly low amount of zinc dialkyl dithiophosphate (ZDDP). The particles were coated with two consecutive films; the initial coating contained silica to enhance amorphous glassy tribofilm formation, followed by a methacrylate film to protect the silica coating and enhance dispersibility in the oil. The functionalized nanoparticles were evaluated for their tribological performance using a high-frequency reciprocating rig, in a cylinder-on-flat configuration. The oil formulations containing ZDDP (350 ppm phosphorus level) and the functionalized nanoparticles resulted in dramatic reductions in the friction coefficient and overall wear compared to the samples containing nonfunctionalized PTFE nanoparticles, ZDDP (350 ppm P), and samples devoid of nanoparticles but containing ZDDP with a 700 ppm P treat rate. XPS and XANES spectroscopy were employed to characterize the tribological films formed on the test samples. The samples with functionalized particles and ZDDP clearly exhibited tribofilms with Si- and F-doped polyphosphates of Zn coupled with the presence of ZnS at the metal-tribofilm interface. On the other hand, oils without the functionalized nanoparticles have oxides of Fe and to a lesser extent short-chain phosphates of Zn. The overall results suggest that the synergism between plasma-coated PTFE nanoparticles and ZDDP contributed to the development of protective tribofilms even at reduced amount of phosphorus in the oil. This new method of employing nanoparticles to deliver novel antifriction and antiwear chemistries at the tribological interfaces stands out as a promising approach to further reduce P levels in oils without compromising friction and wear performance.},
doi = {10.1021/acsami.7b06453},
journal = {ACS Applied Materials and Interfaces},
number = 30,
volume = 9,
place = {United States},
year = {Thu Jul 20 00:00:00 EDT 2017},
month = {Thu Jul 20 00:00:00 EDT 2017}
}