Ultralow Wear PTFE and Alumina Composites: It is All About Tribochemistry

Pitenis, Angela A.; Harris, Kathryn L.; Junk, Christopher P.; Blackman, Gregory S.; Sawyer, W. Gregory; Krick, Brandon A.

doi:10.1007/s11249-014-0445-6

Cited by 134 publications

(131 citation statements)

References 34 publications

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“…Both figures share the same trend as the mechanical evolution of running films reported by Krick et al [24]. Furthermore, there were strong correlations between transfer film mechanical properties and the system wear rater (Figure 7c,d), although the causal relationship remains uncertain; improved transfer film cohesive strength may simply be the consequence of the friction-induced polymer degradation and the accumulation of filler at the sliding interface [27,29,42]. …”

Section: Mechanical Properties Of the Transfer Filmsupporting

confidence: 74%

“…They found that running film hardness and modulus increase with increased sliding distance and decreased wear rates [24]. They suggested that changes in mechanical properties reflect filler accumulation and tribochemical degradation of PTFE, which is consistent with their more recent papers on the evolution of interface chemistry [27,29] and particle enrichment [30]. Ye [42] conducted similar measurements on transfer films from the same system.…”

Section: Mechanical Properties Of the Transfer Filmsupporting

confidence: 67%

“…In addition to producing thinner and more uniform transfer films, low-wear alumina-PTFE transfer films are obviously discolored [13,18,20,[23][24][25][26][27]29,31,32,[37][38][39], which suggests chemical reactions had taken place and possibly enhanced adhesion of the transfer film. In 2013, Ye and Burris used optical microscopy to determine the degree to which transfer films persist during sliding [20].…”

Section: The Effects Of Filler Characteristics On Transfer Films and mentioning

confidence: 99%

“…In 2015, Pitenis et al [29] and Harris et al [27] conducted spectroscopic studies on transfer film chemistry of the same low wear alumina PTFE nanocomposite. After one cycle, they found peaks typically associated with PTFE (Figure 6a).…”

Section: Chemistry Of the Transfer Filmmentioning

confidence: 99%

“…Gong et al [67] and Blanchet et al [44] showed that fillers had no effect on the chemistry of the film-counterface interface of PTFE composites. More than two decades later, Harris et al [27,29] revealed that strong adhesion in the ultra-low-wear alumina PTFE nanocomposite ( Figure 6) system is likely to have chemical origins. This is the only system we know of that has demonstrated adherence and persistence over the course of a typical experiment [20].…”

Section: Adhesion Of the Transfer Filmmentioning

confidence: 99%

See 4 more Smart Citations

A Review of Transfer Films and Their Role in Ultra-Low-Wear Sliding of Polymers

Burris

Xie

2016

Lubricants

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Abstract:In dry sliding conditions, polytetrafluoroethylene (PTFE) composites can form thin, uniform, and protective transfer films on hard, metallic counterfaces that may play a significant role in friction and wear control. Qualitative characterizations of transfer film morphology, composition, and adhesion to the counterface suggest they are all good predictors of friction and, particularly, wear performance. However, a lack of quantitative transfer film characterization methods and uncertainty regarding specific mechanisms of friction and wear control make definitive conclusions about causal relationships between transfer film and tribological properties difficult. This paper reviews the state of the art in the solid lubricant transfer film literature and highlights recent advances in quantitative characterization thereof.

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Section: Mechanical Properties Of the Transfer Filmsupporting

confidence: 74%

Section: Mechanical Properties Of the Transfer Filmsupporting

confidence: 67%

Section: The Effects Of Filler Characteristics On Transfer Films and mentioning

confidence: 99%

Section: Chemistry Of the Transfer Filmmentioning

confidence: 99%

Section: Adhesion Of the Transfer Filmmentioning

confidence: 99%

See 3 more Smart Citations

A Review of Transfer Films and Their Role in Ultra-Low-Wear Sliding of Polymers

Burris

Xie

2016

Lubricants

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Polymer Composites: Reinforcing Fillers

Pegoretti

Dorigato

2019

Encyclopedia of Polymer Science and Technology

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Addition of reinforcing fillers is a well‐established method to enhance mechanical, electrical, and thermal properties of plastics. Formulation and compounding of polymer matrices with inorganic and organic fillers having peculiar morphology enables the development of new multifunctional materials. Among the physical properties affected by the introduction of fillers in plastics, particular attention has been devoted to the mechanical behavior of the resulting composites. Moreover, introduction of inorganic fillers can reduce the cost of plastics, as they are sometime less expensive than polymers. It is well known that with a correct formulation and compounding, the tensile and impact strength and elastic modulus of polymers can be considerably enhanced, allowing to extend the application of plastics in technical fields previously undreamt of. Many other physical properties, such as friction coefficient, molding shrinkage, and weatherability, can be considerably affected by filler addition. This article aims at providing an overview of the various types of fillers available in the market to reinforce plastic products. After a general introduction, the article discusses both particulate microfillers as well as nanostructured fillers. For all the fillers considered, information on their morphological behavior, important physical properties, and production processes are provided. In addition, select examples of fillers’ effectiveness in improving the properties of polymer matrices (thermoplastic, thermosetting, and elastomers) are also presented.

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Ultralow Friction and Wear of Polymer Composites under Extreme Unlubricated Sliding Conditions

Zhang

Chang

et al. 2017

Adv Materials Inter

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Dependence of the tribological behaviors of polyimide‐ and polyetheretherketone‐based composites on pv (pressure × speed) factors is investigated in air ambience. It is demonstrated that the hybrid composites filled with nanosilica/carbon fibers/graphite exhibit ultralow friction and wear under extreme conditions. In particular, the friction coefficients of the hybrid nanocomposites at 40 MPa m s−1 are in the range of 0.03–0.04, which are even lower than those obtained with poly alpha olefin lubrication. Moreover, the friction coefficients are lower than those of carbon fibers reinforced polymer composites ever reported in literatures. In order to reveal the underlying mechanisms of ultralow friction and wear, tribochemistry and tribofilms' nanostructures are comprehensively analyzed. It is identified that chelation of polymeric molecular radicals with steel counterface occurs enhancing tribofilm's bonding strength. Striking orientation of the molecules of remnant polymer in tribofilm is indicative that the film exhibits an easy‐to‐shear characteristic under extreme pv conditions. Nanosilica released onto sliding interface and iron oxide particles abraded from the counterface are thereafter tribosintered into a compact layer, which accounts for the high load‐carrying capability of the tribofilm.

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Ultralow Wear PTFE and Alumina Composites: It is All About Tribochemistry

Cited by 134 publications

References 34 publications

A Review of Transfer Films and Their Role in Ultra-Low-Wear Sliding of Polymers

A Review of Transfer Films and Their Role in Ultra-Low-Wear Sliding of Polymers

Polymer Composites: Reinforcing Fillers

Ultralow Friction and Wear of Polymer Composites under Extreme Unlubricated Sliding Conditions

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