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Brandon A Krick - One of the best experts on this subject based on the ideXlab platform.
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Modeling Wear of Multimaterial Composite Surfaces
Journal of Tribology, 2016Co-Authors: Mark A. Sidebottom, Florian Feppon, Natasha Vermaak, Brandon A KrickAbstract:Iterative numerical wear models provide valuable insight into evolving material surfaces under abrasive wear. In this paper, a holistic numerical scheme for predicting the wear of rubbing elements in tribological systems is presented. In order to capture the wear behavior of a multimaterial surface, a finite difference model is developed. The model determines pressure and height loss along a composite surface as it slides against an abrasive compliant Countersurface. Using Archard's wear law, the corresponding nodal height loss is found using the appropriate material wear rate, applied pressure, and the incremental sliding distance. This process is iterated until the surface profile reaches a steady-state profile. The steady-state is characterized by the incremental height loss at each node being nearly equivalent to the previous loss in height. Several composite topologies are investigated in order to identify key trends in geometry and material properties on wear performance.
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Erratum to: Wear Debris Mobility, Aligned Surface Roughness, and the Low Wear Behavior of Filled Polytetrafluoroethylene
Tribology Letters, 2015Co-Authors: Kathryn L Harris, Kyle G. Rowe, W. Gregory Sawyer, Angela A Pitenis, Mark A. Sidebottom, John F. Curry, Brandon A KrickAbstract:PTFE/α-alumina composites are well known to exhibit very low wear rates compared to unfilled PTFE and various other PTFE-matrix composites. The improved wear life of these composites is attributed in part to the formation of a uniform protective transfer film on the metal Countersurface. It is postulated that the retention of transferred material and the recirculation of third bodies between the transfer film and running surface of the polymer composite are necessary for the maintenance of low wear within this tribological system. The accumulation of these third bodies was observed in reciprocating sliding tests on countersamples prescribed with aligned roughness. Wear performance of the polymer composite was tested as a function of the between the sliding direction and the aligned roughness of the countersample, ranging from parallel to perpendicular to the sliding direction. The wear rate of roughness oriented with the sliding direction was 300 times higher than roughness perpendicular to the sliding direction, revealing the importance of surface morphology and third body retention.
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Wear Debris Mobility, Aligned Surface Roughness, and the Low Wear Behavior of Filled Polytetrafluoroethylene
Tribology Letters, 2015Co-Authors: Kathryn L Harris, Kyle G. Rowe, W. Gregory Sawyer, Angela A Pitenis, Mark A. Sidebottom, John F. Curry, Brandon A KrickAbstract:PTFE/α-alumina composites are well known to exhibit very low wear rates compared to unfilled PTFE and various other PTFE-matrix composites. The improved wear life of these composites is attributed in part to the formation of a uniform protective transfer film on the metal Countersurface. It is postulated that the retention of transferred material and the recirculation of third bodies between the transfer film and running surface of the polymer composite are necessary for the maintenance of low wear within this tribological system. The accumulation of these third bodies was observed in reciprocating sliding tests on countersamples prescribed with aligned roughness. Wear performance of the polymer composite was tested as a function of the between the sliding direction and the aligned roughness of the countersample, ranging from parallel to perpendicular to the sliding direction. The wear rate of roughness oriented with the sliding direction was 300 times higher than roughness perpendicular to the sliding direction, revealing the importance of surface morphology and third body retention.
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ptfe tribology and the role of mechanochemistry in the development of protective surface films
Macromolecules, 2015Co-Authors: Kathryn L Harris, Angela A Pitenis, Gregory W Sawyer, Brandon A Krick, Gregory S Blackman, Daniel J Kasprzak, Christopher P JunkAbstract:The wear and friction behavior of ultralow wear polytetrafluoroethylene (PTFE)/α-alumina composites first described by Burris and Sawyer in 2006 has been heavily studied, but the mechanisms responsible for the 4 orders of magnitude improvement in wear over unfilled PTFE are still not fully understood. It has been shown that the formation of a polymeric transfer film is crucial to achieving ultralow wear on a metal Countersurface. However, the detailed chemical mechanism of transfer film formation and its role in the exceptional wear performance has yet to be described. There has been much debate about the role of chemical interactions between the PTFE, the filler, and the metal Countersurface, and some researchers have even concluded that chemical changes are not an important part of the ultralow wear mechanism in these materials. Here, a “stripe” test allowed detailed spectroscopic studies of PTFE/α-alumina transfer films in various stages of development, which led to a proposed mechanism which accounts ...
Dirk J. Schipper - One of the best experts on this subject based on the ideXlab platform.
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The Role of Phosphate-Conversion Coatings in the Makeup and Sealing Ability of Casing Connections
SPE Drilling & Completion, 2018Co-Authors: Dennis Ernens, Egbert J. Van Riet, Matthias B. De Rooij, H.r. Pasaribu, Willem Maarten Van Haaften, Dirk J. SchipperAbstract:Phosphate-conversion coatings are widely used on (premium) casing connections for protection against corrosion. These coatings provide galling protection in conjunction with lubricant. The friction and wear that occur during makeup and subsequent load cycling strongly influence the sealing performance of the metal/metal seal. Therefore, phosphate-conversion coatings play an important role in the sealing performance of metal/metal seals. An extensive test program was set up to investigate the role of phosphate coatings during makeup and in the subsequent sealing of the metal/metal seal. With pin-on-disk, anvil-on-strip, and ring-on-ring tests, the interactions between the substrate, lubricant, and phosphate coating were investigated. A comparison was made between uncoated and coated specimens using base greases and formulated greases: API-modified lubricant and two commercially available yellow dopes. The results indicate a strong influence of the phosphate coating leading to damage-free makeup, low wear, and less dependence on the lubricant for optimal sealing ability. This is attributed to the formation of a hard and smooth dissimilar surface, the ability to adsorb the lubricant, and the generation of a transfer layer on the uncoated Countersurface. It is concluded that taking the interaction with phosphates into account could enable lubricants to be tailored for sealing performance, and thus can ease the transition to environmentally friendly rated lubricants.
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Modelling material transfer on a single asperity scale
Wear, 2013Co-Authors: M.b. De Rooij, G. Van Der Linde, Dirk J. SchipperAbstract:In many adhesive wear processes, transfer of material from the donor surface results in the formation of lumps or a continuous layer on the Countersurface. The morphology of the transferred layer is important for the tribological behaviour of the resulting interface. If the lumps formed on the Countersurface are harder than the donor surface, abrasion of the donor surface will be the consequence of adhesive lump formation. In particular, the formation of sharp and hard lumps will be detrimental for the donor surface. A model will be presented for the geometrical development of a single lump such that the transferred material forms a lump that can resist the forces that will act on it. The initial geometry of the individual ploughing asperity is based on measured height data of the harder, ploughing surface and is represented by an equivalent pyramidal shape with a hexagonal base. After determination of the initial shape, geometrical changes due to material transfer are modelled. An important aspect in this is that the shape should be mechanically stable, so not fail due the ploughing forces. Based on this model, the geometrical development of an asperity over time is simulated. From the results it can be seen that the orientation of the asperity with respect to the velocity vector is an important factor. The best orientation of the asperity to reduce lump growth is an angle of around 10° between the velocity vector and the major length of the asperity. Contrary to the orientation, the geometrical dimensions of the asperity are of minor importance for lump growth. Typical geometrical characteristics of the growing lump are compared with experiments. The results of the model will be discussed in the context of galling behaviour taking place in deep drawing processes.
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influence of Countersurface materials on dry sliding performance of cuo y tzp composite at 600oc
Journal of The European Ceramic Society, 2012Co-Authors: Mahdiar Valefi, B. Pathiraj, Matthijn De Rooij, Erik G. De Vries, Dirk J. SchipperAbstract:Dry sliding wear tests on 5 wt.% copper oxide doped yttria stabilized zirconia polycrystals (CuO?TZP) composite have been performed against alumina, zirconia and silicon nitride Countersurfaces at 600 °C. The influences of load and Countersurface materials on the tribological performance of this composite have been studied. The friction and wear test results indicate a low coefficient of friction and specific wear rate for alumina and zirconia Countersurfaces at F = 1 N load (maximum Hertzian pressure ~0.5 GPa). Examination of the worn surfaces using scanning electron microscope/energy dispersive spectroscopy confirmed the presence of copper rich layer at the edge of wear scar on the alumina and zirconia Countersurfaces. However, Si3N4 Countersurface sliding against CuO?TZP shows a relatively higher coefficient of friction and higher wear at 1 N load condition. These results suggest that the Countersurface material significantly affect the behavior of the third body and self-lubricating ability of the composite.
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Influence of Countersurface materials on dry sliding performance of CuO/Y-TZP composite at 600oC
Journal of the European Ceramic Society, 2012Co-Authors: Mahdiar Valefi, B. Pathiraj, Matthijn De Rooij, Erik G. De Vries, Dirk J. SchipperAbstract:Dry sliding wear tests on 5 wt.% copper oxide doped yttria stabilized zirconia polycrystals (CuO?TZP) composite have been performed against alumina, zirconia and silicon nitride Countersurfaces at 600 °C. The influences of load and Countersurface materials on the tribological performance of this composite have been studied. The friction and wear test results indicate a low coefficient of friction and specific wear rate for alumina and zirconia Countersurfaces at F = 1 N load (maximum Hertzian pressure ~0.5 GPa). Examination of the worn surfaces using scanning electron microscope/energy dispersive spectroscopy confirmed the presence of copper rich layer at the edge of wear scar on the alumina and zirconia Countersurfaces. However, Si3N4 Countersurface sliding against CuO?TZP shows a relatively higher coefficient of friction and higher wear at 1 N load condition. These results suggest that the Countersurface material significantly affect the behavior of the third body and self-lubricating ability of the composite.
Mahdiar Valefi - One of the best experts on this subject based on the ideXlab platform.
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influence of Countersurface materials on dry sliding performance of cuo y tzp composite at 600oc
Journal of The European Ceramic Society, 2012Co-Authors: Mahdiar Valefi, B. Pathiraj, Matthijn De Rooij, Erik G. De Vries, Dirk J. SchipperAbstract:Dry sliding wear tests on 5 wt.% copper oxide doped yttria stabilized zirconia polycrystals (CuO?TZP) composite have been performed against alumina, zirconia and silicon nitride Countersurfaces at 600 °C. The influences of load and Countersurface materials on the tribological performance of this composite have been studied. The friction and wear test results indicate a low coefficient of friction and specific wear rate for alumina and zirconia Countersurfaces at F = 1 N load (maximum Hertzian pressure ~0.5 GPa). Examination of the worn surfaces using scanning electron microscope/energy dispersive spectroscopy confirmed the presence of copper rich layer at the edge of wear scar on the alumina and zirconia Countersurfaces. However, Si3N4 Countersurface sliding against CuO?TZP shows a relatively higher coefficient of friction and higher wear at 1 N load condition. These results suggest that the Countersurface material significantly affect the behavior of the third body and self-lubricating ability of the composite.
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Wear and friction of self-lubricating CuO-TZP composites
2012Co-Authors: Mahdiar ValefiAbstract:In certain applications, including high temperature or vacuum environments, liquid lubricants or greases are not stable. Solid lubricants are potentially suitable candidates for the reduction of friction and wear. Ceramic materials are a suitable candidate for harsh environments such as high temperatures and vacuum. Ceramic components are generally lubricated by thin solid films to achieve low friction and wear. The lifetime of such films is inevitably limited. By incorporating solid lubricant reservoirs into a hard ceramic matrix, friction and wear can be decreased during sliding by realizing a gradual replenishment of the soft solid lubricant to the surface. Therefore, it is of great importance to study the self-lubricating ability of the ceramic contact. In this thesis, a CuO doped zirconia composite has been chosen as a self-lubricating ceramic composite system. The tribological performance of the ceramic composite has been systematically investigated. To understand the self-lubricating ability of the composite, the friction behaviour has been studied at different temperature levels. First, dry sliding tests were conducted at room temperature using different loads and sliding velocities as well as Countersurfaces. The wear mechanisms have been investigated using different characterization methods. At room temperature, 5CuO-TZP only shows low friction and wear against an alumina Countersurface. Similar dry sliding tests have been carried out at elevated temperatures. A coefficient of friction of 0.35 and a specific wear rate less than 10-6 mm3/Nm were obtained at 600 °C for CuO-TZP sliding against an alumina Countersurface. It has been found that a soft copper rich (third body) layer is formed at the interface between the sliding components. The formation of the soft layer as well as the wear mechanism has been explained. A physically-based model has been developed which includes the processes responsible for maintaining the soft third body layer at the interface. The model can predict the thickness of the third body layer under different tribological conditions in the mild wear regime. It can be concluded that the tribological performance of CuO-TZP under dry contact conditions strongly depends on the operational conditions.
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Influence of Countersurface materials on dry sliding performance of CuO/Y-TZP composite at 600oC
Journal of the European Ceramic Society, 2012Co-Authors: Mahdiar Valefi, B. Pathiraj, Matthijn De Rooij, Erik G. De Vries, Dirk J. SchipperAbstract:Dry sliding wear tests on 5 wt.% copper oxide doped yttria stabilized zirconia polycrystals (CuO?TZP) composite have been performed against alumina, zirconia and silicon nitride Countersurfaces at 600 °C. The influences of load and Countersurface materials on the tribological performance of this composite have been studied. The friction and wear test results indicate a low coefficient of friction and specific wear rate for alumina and zirconia Countersurfaces at F = 1 N load (maximum Hertzian pressure ~0.5 GPa). Examination of the worn surfaces using scanning electron microscope/energy dispersive spectroscopy confirmed the presence of copper rich layer at the edge of wear scar on the alumina and zirconia Countersurfaces. However, Si3N4 Countersurface sliding against CuO?TZP shows a relatively higher coefficient of friction and higher wear at 1 N load condition. These results suggest that the Countersurface material significantly affect the behavior of the third body and self-lubricating ability of the composite.
Thierry A. Blanchet - One of the best experts on this subject based on the ideXlab platform.
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Modeling temperature rise in multi-track reciprocating frictional sliding:
Proceedings of the Institution of Mechanical Engineers Part J: Journal of Engineering Tribology, 2021Co-Authors: Thierry A. BlanchetAbstract:As in various manufacturing processes, in sliding tests with scanning motions to extend the sliding distance over fresh Countersurface, temperature rise during any pass is bolstered by heating duri...
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Wear reduction mechanisms within highly wear-resistant graphene- and other carbon-filled PTFE nanocomposites
Wear, 2020Co-Authors: Suvrat Bhargava, Mary E. Makowiec, Thierry A. BlanchetAbstract:Abstract In recent years, a few select carbonaceous fillers with nanometer-size dimensions, such as graphene platelets, activated carbon nanoparticles and carbon nanotubes, have been shown to reduce the wear rates of PTFE to levels approaching 10−7 mm3/Nm and below. X-ray diffraction (XRD) and attenuated total reflectance (ATR) mode IR spectroscopy are used to show that these highly effective fillers provide wear resistance to PTFE through shared mechanisms. These mechanisms are also shown to operate in highly wear-resistant composites of PTFE with nanometer-sized particles of α-phase alumina. Addition of these highly effective fillers to PTFE results in a greater resemblance of the crystalline structure of PTFE at room temperature with a tougher and higher temperature phase. When slid against steel Countersurfaces under ambient conditions, these fillers embedded within the PTFE matrix also enable the formation of robust transfer films through the formation of metal chelates.
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coupled effect of filler content and Countersurface roughness on ptfe nanocomposite wear resistance
Tribology Letters, 2010Co-Authors: Thierry A. Blanchet, Sashi S Kandanur, Linda S. SchadlerAbstract:In tests of PTFE with 2.9% volume content alpha-phase alumina nanoparticles (40 or 80 nm) in sliding reciprocation against polished steel, wear rates of ~10−7 mm3/Nm were measured which is four orders-of-magnitude lower than unfilled PTFE and two orders-of-magnitude lower than with microparticles (0.5 or 20 μm) of more conventional filler size. This was similar to that previously reported in unidirectional sliding, and did not vary greatly with stroke of reciprocation. For a microfilled PTFE, the wear rate gradually increased towards that of unfilled PTFE as filler content was reduced, whereas nanofilled PTFE maintained relatively constant ~10−7 mm3/Nm to filler contents as low as 0.18% before reverting towards the rapid wear rate of unfilled PTFE. Lightly filled nanocomposites depend upon low Countersurface roughness to maintain such low wear rate, and with increasing roughness the wear rate was found to transition at a critical value to a wear rate of ~10−5 mm3/Nm. Nanocomposites with higher filler contents were able to retain the low wear rates against rougher Countersurfaces, as the critical roughness at which this wear resistance was lost tended to increase with the square of the filler content. Upon encountering extremely high Countersurface roughness in the range Ra = 6–8 μm, nanocomposites at each filler content eventually increased in wear rate to ~10−4 mm3/Nm. The steel Countersurface did not appear to play an important role in the extreme wear resistance of these alumina nanofilled PTFE composites, as comparable performance was also displayed against alumina Countersurfaces.
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Transfer Solid Lubrication of Aluminum Sliding Contacts
Tribology Transactions, 2008Co-Authors: Edin E. Balic, Thierry A. BlanchetAbstract:The effects of transfer from solid lubricant sticks of unfilled, glass-filled, and bronze-filled PTFE on the room-temperature wear and friction of trailing primary contacts of aluminum (6061 T6) rods in repetitive intermittent contacts were investigated in a ring-on-rod configuration. The materials of the ring Countersurfaces upon which the solid lubricants transferred and against which the trailing aluminum rods wore included steel, aluminum, copper, and an oxide dispersion-strengthened copper alloy. This sliding of the unlubricated copper ring Countersurfaces against the aluminum led to the roughening of the copper as large (> 1 mm) aluminum particles embedded themselves upon the Countersurface, with consequent transitions in the aluminum wear rate and the coefficient of friction to values exceeding 6 × 10− 3 mm3/Nm and 0.6, respectively, after an incubation period of several initial contacts of lower wear rate and friction. The other ring Countersurface materials resulted in similarly high aluminum rod...
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The effect of Countersurface thermal properties on the melt wear of aluminum
Wear, 2007Co-Authors: Edin E. Balic, Thierry A. BlanchetAbstract:The effect thermal properties of Countersurface materials may have on the melt wear of aluminum is investigated. Aluminum (6061 T6) rod specimens were tested in a ring-on-rod configuration against five different ring Countersurface materials: stainless steel (304); steel (4130); aluminum (6061 T6); copper (C101); and Glidcop (Al-25). In each test, sliding contact was produced for a brief 2s duration at pressure p = 1.76 MPa and speed v = 5.6 m/s during which friction was measured while rod wear was characterized by post-test mass measurement. At this common combination of contact pressure and sliding speed, heated tests against each Countersurface material were conducted at far-field surrounding temperatures of 260, 300 and 330 °C. Aluminum rod wear rates ranged from 102 x 10 -3 mm 3 /Nm against stainless steel to 1.23 x 10 -3 mm 3 /Nm against copper at 330 °C, from 59.0 x 10 -3 mm 3 /Nm against stainless steel to 0.66 x 10 -3 mm 3 /Nm against copper at 300 °C, and from 30.9 x 10 -3 mm 3 /Nm against stainless steel to 0.68 x 10 -3 mm 3 /Nm against copper at 260 °C. Baseline tests were also conducted at room temperature, where rod wear rates all remained below 0.5 x 10 -3 mm 3 /Nm as rod melt could not be achieved by sliding contact with any of the ring Countersurfaces at such low far-field temperatures for the given contact pressure and sliding speed conditions. In heated tests, rod wear increases with increasing bulk temperature, since a smaller portion of the frictional heat is required to bring the sliding interface to the aluminum rod's melt temperature, thus leaving a greater balance of the frictional heat to go into the aluminum rod's phase change and melt wear. Rod melt wear increases with variation of ring Countersurface material as follows: copper; Glidcop; aluminum; steel; stainless steel. This variation was found to be in agreement with the analytical prediction of the ring material's conduction effectiveness in partitioning heat away from the contact interface, thus reducing the heat going into the aluminum rod and its melting.
Kathryn L Harris - One of the best experts on this subject based on the ideXlab platform.
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Erratum to: Wear Debris Mobility, Aligned Surface Roughness, and the Low Wear Behavior of Filled Polytetrafluoroethylene
Tribology Letters, 2015Co-Authors: Kathryn L Harris, Kyle G. Rowe, W. Gregory Sawyer, Angela A Pitenis, Mark A. Sidebottom, John F. Curry, Brandon A KrickAbstract:PTFE/α-alumina composites are well known to exhibit very low wear rates compared to unfilled PTFE and various other PTFE-matrix composites. The improved wear life of these composites is attributed in part to the formation of a uniform protective transfer film on the metal Countersurface. It is postulated that the retention of transferred material and the recirculation of third bodies between the transfer film and running surface of the polymer composite are necessary for the maintenance of low wear within this tribological system. The accumulation of these third bodies was observed in reciprocating sliding tests on countersamples prescribed with aligned roughness. Wear performance of the polymer composite was tested as a function of the between the sliding direction and the aligned roughness of the countersample, ranging from parallel to perpendicular to the sliding direction. The wear rate of roughness oriented with the sliding direction was 300 times higher than roughness perpendicular to the sliding direction, revealing the importance of surface morphology and third body retention.
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Wear Debris Mobility, Aligned Surface Roughness, and the Low Wear Behavior of Filled Polytetrafluoroethylene
Tribology Letters, 2015Co-Authors: Kathryn L Harris, Kyle G. Rowe, W. Gregory Sawyer, Angela A Pitenis, Mark A. Sidebottom, John F. Curry, Brandon A KrickAbstract:PTFE/α-alumina composites are well known to exhibit very low wear rates compared to unfilled PTFE and various other PTFE-matrix composites. The improved wear life of these composites is attributed in part to the formation of a uniform protective transfer film on the metal Countersurface. It is postulated that the retention of transferred material and the recirculation of third bodies between the transfer film and running surface of the polymer composite are necessary for the maintenance of low wear within this tribological system. The accumulation of these third bodies was observed in reciprocating sliding tests on countersamples prescribed with aligned roughness. Wear performance of the polymer composite was tested as a function of the between the sliding direction and the aligned roughness of the countersample, ranging from parallel to perpendicular to the sliding direction. The wear rate of roughness oriented with the sliding direction was 300 times higher than roughness perpendicular to the sliding direction, revealing the importance of surface morphology and third body retention.
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ptfe tribology and the role of mechanochemistry in the development of protective surface films
Macromolecules, 2015Co-Authors: Kathryn L Harris, Angela A Pitenis, Gregory W Sawyer, Brandon A Krick, Gregory S Blackman, Daniel J Kasprzak, Christopher P JunkAbstract:The wear and friction behavior of ultralow wear polytetrafluoroethylene (PTFE)/α-alumina composites first described by Burris and Sawyer in 2006 has been heavily studied, but the mechanisms responsible for the 4 orders of magnitude improvement in wear over unfilled PTFE are still not fully understood. It has been shown that the formation of a polymeric transfer film is crucial to achieving ultralow wear on a metal Countersurface. However, the detailed chemical mechanism of transfer film formation and its role in the exceptional wear performance has yet to be described. There has been much debate about the role of chemical interactions between the PTFE, the filler, and the metal Countersurface, and some researchers have even concluded that chemical changes are not an important part of the ultralow wear mechanism in these materials. Here, a “stripe” test allowed detailed spectroscopic studies of PTFE/α-alumina transfer films in various stages of development, which led to a proposed mechanism which accounts ...
