Journal ArticleDOI
In Vacuo Tribological Behavior of Polytetrafluoroethylene (PTFE) and Alumina Nanocomposites: The Importance of Water for Ultralow Wear
Jeffrey J. Ewin,Brandon A. Krick +1 more
TLDR
In this article, the wear and friction behavior of PTFE and nanocomposites were evaluated under a broad range of vacuum environments from 760 to 4 9 10 -6 Torr.Abstract:
Polytetrafluoroethylene (PTFE) is widely regarded as an excellent candidate for solid lubrication in vacuum. However, it is often precluded from many prac- tical applications due to its intrinsically high wear rate. Over the past decade, it has been discovered that small loading fractions of alumina nanofillers can increase the wear resistance of PTFE by three to four orders of mag- nitude. This dramatic increase in wear resistance has in turn prompted numerous tribological studies to examine the robustness of this performance. In this study, the wear and friction behavior of unfilled PTFE and PTFE and alumina nanocomposites were evaluated under a broad range of vacuum environments from 760 to 4 9 10 -6 Torr. The nanocomposites of PTFE/alumina showed a dramatic increase in wear of over two orders of magnitude at the highest vacuum conditions. There appears to be an optimal vacuum environment around 1-10 Torr, in which these samples achieved the lowest wear rates of approximately 2.5 9 10 -7 mm 3 /(Nm).read more
Citations
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Journal ArticleDOI
PTFE Tribology and the Role of Mechanochemistry in the Development of Protective Surface Films
Kathryn L. Harris,Angela A. Pitenis,W. Gregory Sawyer,Brandon A. Krick,Gregory S. Blackman,Daniel J. Kasprzak,Christopher P. Junk +6 more
TL;DR: In this paper, the role of chemical interactions between the PTFE, the filler, and the metal countersurface has been investigated, and it has been shown that chemical changes are not an important part of the ultralow wear mechanism in these materials.
Journal ArticleDOI
Ultralow Wear PTFE and Alumina Composites: It is All About Tribochemistry
Angela A. Pitenis,Kathryn L. Harris,Christopher P. Junk,Gregory S. Blackman,W. Gregory Sawyer,Brandon A. Krick +5 more
TL;DR: In this paper, the authors investigated the role of tribochemistry in the wear performance of PTFE and alumina composites and found that tribochemistry plays a major role in the significant wear rate reduction achieved in PTFEs and aluminas composites.
Journal ArticleDOI
Mechanistic Studies in Friction and Wear of Bulk Materials
TL;DR: In this article, a review of recent contributions from recent experimental investigations of three classes of materials that exhibit uniquely contrasting tribological behaviors: metals, polymers, and ionic solids is presented.
Journal ArticleDOI
A Review of Transfer Films and Their Role in Ultra-Low-Wear Sliding of Polymers
TL;DR: A review of transfer film characterization methods for friction and wear control can be found in this article, where the state-of-the-art in solid lubricant transfer film literature is summarized.
Journal ArticleDOI
Ultralow wear fluoropolymer composites: Nanoscale functionality from microscale fillers
Brandon A. Krick,Angela A. Pitenis,Kathryn L. Harris,Christopher P. Junk,W. Gregory Sawyer,Scott C. Brown,H. David Rosenfeld,Daniel J. Kasprzak,Ross S. Johnson,Christopher Chan,Gregory S. Blackman +10 more
TL;DR: In this paper, a combination of X-ray microtomography, transmission electron microscopy and infrared spectroscopy reveal nanoscale alumina fragments accumulated in the tribofilms.
References
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Journal ArticleDOI
The wear of metals under unlubricated conditions
J. F. Archard,W. Hirst +1 more
TL;DR: The wear of a wide range of material combinations has been studied in unlubricated conditions as mentioned in this paper, and the wear rate is accurately proportional to the load for only a limited number of combinations but there are many other examples for which the relation between wear rate and load shows only a small deviation from direct proportionality.
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A study on the friction and wear behavior of PTFE filled with alumina nanoparticles
TL;DR: In this article, a solid lubricant composite material was made by compression molding PTFE and 40nm alumina particles using a jet milling apparatus and tested against a polished stainless steel counterface on a reciprocating tribometer.
Journal ArticleDOI
A review of the influence of environmental humidity and water on friction, lubrication and wear
TL;DR: A review of the various ways in which humidity and liquid water can influence the friction and wear of metals, polymers, carbons and graphite, lamellar solid lubricants and ceramics is given in this article.
Journal ArticleDOI
Sliding wear mechanism of polytetrafluoroethylene (PTFE) and PTFE composites
TL;DR: In this article, a fracture-based model describes the onset of severe wear and attendant changes in debris morphology, and the wear-reducing effectiveness of three fillers is investigated as a function of speed.
Journal ArticleDOI
The mechanism of wear of polytetrafluoroethylene
TL;DR: In this paper, the effect of speed and temperature on the wear rate of polytetrafluoroethylene (PTFE) has been studied and a master curve has been proposed to express the effect.