The action of fillers in the modification of the tribological behavior of polymers

Bahadur, S.; Gong, Dirong

doi:10.1016/0043-1648(92)90029-8

Cited by 139 publications

(78 citation statements)

References 22 publications

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“…Although Bahadur and Tabor found no evidence that transfer films persist during sliding contact, Bahadur and Gong found that wear rate correlated strongly with evidence of chemical reactions in the transfer films [3]. They suggested that reactive fillers help increase transfer film adhesion and thereby reduce wear relative to inert fillers.…”

Section: Transfer Films and Their Link To Low Wearmentioning

confidence: 97%

“…An important advantage of the PTFE composite-metal counterface sliding system is its ability to provide low friction and low wear in dry sliding conditions. The self-lubricating properties of this system are thought to be largely attributable to its ability to deposit a thin and protective layer of polymer onto the counterface, the so-called transfer film [3]. Contrary to the conventional wisdom that PTFE resists adhesion, Tabor et al showed that PTFE readily transfers to surfaces it contacts [4,5].…”

Section: Introductionmentioning

confidence: 97%

“…Briscoe first suggested transfer film adhesion is the dominant wear-reducing factor in polymer composites and is caused by filler-induced polymer degradation [8]. Bahadur and Gong concluded that filler chemistry was critical because decomposition enabled the filler to form a link between the transfer film and the counterface [3]. Schwartz and Bahadur attempted to make the first direct measurements of transfer film bond strength by gluing a copper tab to the transfer film formed by a PPS nanocomposite against steel.…”

Section: Transfer Films and Their Link To Low Wearmentioning

confidence: 99%

“…The adhesion strength between transfer films and counterfaces is among the most frequently discussed mechanisms of wear reduction for polymeric solid lubricants [3,[8][9][10][58][59][60][61][62]. Adhesion is often thought of in terms of bonding and may have physical or chemical origins [44,[63][64][65][66][67].…”

Section: Adhesion Of the Transfer Filmmentioning

confidence: 99%

“…Incorporation of micro-scaled fillers has been shown to reduce wear rates of PTFE typically bỹ 100ˆwith >20 wt % filler loading [3,[6][7][8][9][10][11]. Early on, the wear-mitigating effect of these particles was attributed to preferential support of the normal load by the filler and disruption of subsurface crack propagation [6,12].…”

Section: Introductionmentioning

confidence: 99%

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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: Transfer Films and Their Link To Low Wearmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 97%

Section: Transfer Films and Their Link To Low Wearmentioning

confidence: 99%

Section: Adhesion Of the Transfer Filmmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Burris

Xie

2016

Lubricants

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Effect of rare earth compounds as fillers on friction and wear behaviors of PTFE-based composites

Zhang¹,

Xue²,

Liu³

et al. 1999

J. Appl. Polym. Sci.

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ABSTRACT:The friction and wear behaviors of polytetrafluoroethylene (PTFE)-based composites filled with rare earth compounds CeO 2 , CeF 3 , and La 2 O 3 in volume content from 5 to 30% sliding against GCr15 bearing steel under dry friction conditions were evaluated by using an MHK-500 ring-block wear tester. The wear debris and the worn surfaces of the PTFE composites were investigated by using a scanning electron microscope (SEM), whereas the transfer films of the PTFE composites formed on the surface of GCr15 bearing steel were examined by using an optical microscope. Experimental results show that the antiwear properties of the PTFE composites can be improved greatly by filling PTFE with different contents of CeO 2 , CeF 3 , and La 2 O 3 , and that the wear of the PTFE composites can be decreased by one to two orders of magnitude compared with that of pure PTFE. The wear of the CeF 3 -filled PTFE composite decreases with the increase of the content of CeF 3 from 5 to 30 vol %, but its friction coefficient increases with the increase of the content of CeF 3 in PTFE. When the content of CeO 2 in PTFE is 15 vol %, the friction and wear properties of CeO 2 -filled PTFE composite are the best. But when the content of La 2 O 3 in PTFE is between 15 and 20 vol %, the PTFE composite filled with La 2 O 3 exhibits excellent friction and wearreducing properties. Microscope investigations show that rare earth compounds CeO 2 , CeF 3 , and La 2 O 3 in PTFE not only inhibit the large-scale destruction of the banded structure of PTFE but also enhance the adhesion of the transfer films of the PTFE composites to the surface of GCr15 bearing steel, so they greatly reduce the wear of the PTFE composites. With the increase of the content of CeO 2 , CeF 3 , and La 2 O 3 in PTFE, the actions with which the rare earth compounds inhibit the large-scale destruction of the banded structure of PTFE are enhanced; so the wear of the PTFE composites decreases. Meanwhile, because CeO 2 -and La 2 O 3 -filled PTFE composites can easily form uniform transfer films on the surface of GCr15 bearing steel, the friction and wear-reducing properties of CeO 2 -and La 2 O 3 -filled PTFE composites are better than those of CeF 3 -filled PTFE composites under dry friction conditions.

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Friction and wear characteristics of metal sulfides and graphite-filled PTFE composites under dry and oil-lubricated conditions

Zhang

Xue

Liu

et al. 1999

J. Appl. Polym. Sci.

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Five kinds of polytetrafluoroethylene (PTFE)-based composites, pure PTFE, PTFE ϩ 30(v)% MoS 2 , PTFE ϩ 30(v)% PbS, PTFE ϩ 30(v)% CuS, and PTFE ϩ 30(v)% graphite (GR) composites, were first prepared. Then the friction and wear properties of these PTFE composites, sliding against GCr15-bearing steel under both dry and liquid paraffin-lubricated conditions, were studied by using an MHK-500 ring-on-block wear tester. Finally, the worn surfaces and the transfer films of the PTFE composites formed on the surface of GCr15 bearing steel were investigated by using a scanning electron microscope (SEM) and an optical microscope, respectively. Experimental results show that filling with MoS 2 , PbS, CuS, or graphite to PTFE can reduce the wear of the PTFE composites by two orders of magnitude compared to that of pure PTFE under dry friction conditions. However, the friction and wear-reducing properties of these PTFE composites can be greatly improved by lubrication with liquid paraffin. Investigations of transfer films show that MoS 2 , PbS, CuS, and graphite promote the transfer of the PTFE composites onto the surface of GCr15-bearing steel under dry friction conditions, but the transfer of the PTFE composites onto the surface of GCr15-bearing steel can be greatly reduced by lubrication with liquid paraffin. SEM examinations of worn surfaces show that with lubrication of liquid paraffin, the creation and development of the cracks occurred on the worn surfaces of the PTFE composites under load, which reduces the load-supporting capacity of the PTFE composites. This would lead to the deterioration of the friction and wear properties of the PTFE composites under higher loads (Ͼ600N).

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The action of fillers in the modification of the tribological behavior of polymers

Cited by 139 publications

References 22 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

Effect of rare earth compounds as fillers on friction and wear behaviors of PTFE-based composites

Friction and wear characteristics of metal sulfides and graphite-filled PTFE composites under dry and oil-lubricated conditions

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