Ultralow Wear PTFE-Based Polymer Composites—The Role of Water and Tribochemistry

Campbell, Kasey L.; Sidebottom, Mark A.; Atkinson, Cooper C.; Babuska, Tomas F.; Kolanovic, Claudia A.; Boulden, Brian J.; Junk, Christopher P.; Krick, Brandon A.

doi:10.1021/acs.macromol.9b00316

Cited by 80 publications

(66 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…According to previous studies, the formation of PEEK polymeric transfer film on counter face parts was mainly due to its adhesion properties 8,12,13 . As the experiments went on, PEEK adhered on the counter face parts and formed the transfer film under high contact pressure 35 . The increase in the contact pressure led to an increase in the amount of PEEK adhered to the surface.…”

Section: Discussionmentioning

confidence: 85%

Insight into water lubrication performance of polyetheretherketone

Guo

Yuan

2020

J of Applied Polymer Sci

View full text Add to dashboard Cite

Polyetheretherketone (PEEK) is a kind of polymer with excellent mechanical properties combined with good wear resistance and has been widely used in the engineering field. In order to explore the possibility for PEEK using as a water-lubricated bearing material, an in-depth study on the water lubrication performance of PEEK was conducted by using a series of experiments. The water lubrication performances combined with the lubricating mechanism were evaluated both by the friction coefficient and by the wear behavior of PEEK. The results indicated that PEEK was suitable for water-lubricated bearing productions. The water film could form effectively between the friction pairs under high sliding velocity, while the transfer film could form under low sliding velocity. Both the water film and the transfer film could improve the water lubrication performance for the friction pairs. Moreover, sliding velocities and contact pressures highly influence the water lubrication performance of PEEK. The increase in contact pressure or the decrease in sliding velocity would exacerbate the wear of material. The stick-slip phenomena also occurred on the specimens under low sliding velocity. The main purpose of this study is to provide an experimental basis for PEEK using as a waterlubricated bearing material.

show abstract

Section: Discussionmentioning

confidence: 85%

Insight into water lubrication performance of polyetheretherketone

Guo

Yuan

2020

J of Applied Polymer Sci

View full text Add to dashboard Cite

show abstract

“…We note that in our simulations no chemical reactions are considered between PTFE and the surfaces and adhesion is fully determined by physisorption. PTFE chains that break due to shear forces [35,36] can chemisorb on the surface which should further enhance the PTFE adhesion on the surfaces and in turn the PTFE transfer film formation.…”

Section: Discussionmentioning

confidence: 99%

A Combined Experimental and Atomistic Investigation of PTFE Double Transfer Film Formation and Lubrication in Rolling Point Contacts

et al. 2021

View full text Add to dashboard Cite

Solid lubricants such as polytetrafluoroethylene (PTFE) are used in rolling-element bearings (REBs) when conventional lubrication (i.e. by fluids or greases) cannot be applied owing to extreme operating conditions (e.g. high temperatures or vacuum). Often a double transfer film mechanism is used with a cage acting as a lubricant reservoir resupplying the REB with solid lubricant by cage wear. An increase in service life of such bearings requires a better understanding of the transfer processes in the sliding and rolling contacts. Here, we investigate the effect of PTFE resupply on friction and lubricant film formation in a steel/steel and steel/glass rolling contact by tribometry and classical molecular dynamics (MD). A ball-on-disk tribometer is enhanced by a pin-on-disk sliding contact that transfers PTFE to the disk. The experiment allows simultaneous in situ measurement of friction and film thickness by white light interferometry in the rolling point contact. Increasing the pin load results in an increased PTFE film thickness in the rolling contact accompanied by a significant decrease in friction. To elucidate the observed film transfer and friction mechanism, sliding MD simulations with a newly developed density-functional-based, non-reactive force field for PTFE-lubricated iron oxide surfaces are performed. A strong adhesion of PTFE chains to iron oxide drives transfer film formation, whilst shear-induced chain alignment within PTFE results in reduced friction. The simulations reveal an anti-correlation between PTFE film thickness and friction coefficient—in agreement with the experiments. These investigations are a first step towards methods to control PTFE transfer film formation in REBs. Graphic Abstract

show abstract

“…We note that in our simulations no chemical reactions are considered between PTFE and the surfaces and adhesion is fully determined by physisorption. PTFE chains that break due to shear forces [29,30] can chemisorb on the surface which should further enhance the PTFE adhesion on the surfaces and in turn the PTFE transfer film formation. Furthermore, our simulations show that the arrangement of the molecules is crucial for friction.…”

Section: Discussionmentioning

confidence: 99%

A Combined Experimental and Atomistic Investigation of PTFE Double Transfer Film Formation and Lubrication in Rolling Point Contacts

Goeldel

Reichenbach

König

et al. 2021

Preprint

View full text Add to dashboard Cite

Solid lubricants such as polytetrafluoroethylene (PTFE) are used in rolling-element bearings (REBs) when conventional lubrication (i.e. by fluids or greases) cannot be applied owing to extreme operating conditions (e.g. high temperatures or vacuum). Often a double transfer film mechanism is used with a cage acting as a lubricant reservoir resupplying the REB with solid lubricant by cage wear. An increase in service life of such bearings requires a better understanding of the transfer processes in the sliding and rolling contacts. Here, we investigate the effect of PTFE resupply on friction and lubricant film formation in a steel/steel and steel/glass rolling contact by tribometry and classical molecular dynamics (MD). A ball-on-disk tribometer is enhanced by a pin-on-disk sliding contact that transfers PTFE to the disk. The experiment allows simultaneous in situ measurement of friction and film thickness by white light interferometry in the rolling point contact. Increasing the pin load results in an increased PTFE film thickness in the rolling contact accompanied by a significant decrease in friction. To elucidate the observed film transfer and friction mechanism, sliding MD simulations with a newly developed density-functional-based, non-reactive force field for PTFE-lubricated iron oxide surfaces are performed. A strong adhesion of PTFE chains to iron oxide drives transfer film formation, while shear-induced chain alignment within PTFE results in reduced friction. The simulations reveal an anti-correlation between PTFE film thickness and friction coefficient – in agreement with the experiments. These investigations are a first step towards methods to control PTFE transfer film formation in REBs.

show abstract

Ultralow Wear PTFE-Based Polymer Composites—The Role of Water and Tribochemistry

Cited by 80 publications

References 64 publications

Insight into water lubrication performance of polyetheretherketone

Insight into water lubrication performance of polyetheretherketone

A Combined Experimental and Atomistic Investigation of PTFE Double Transfer Film Formation and Lubrication in Rolling Point Contacts

A Combined Experimental and Atomistic Investigation of PTFE Double Transfer Film Formation and Lubrication in Rolling Point Contacts

Contact Info

Product

Resources

About