Low temperature investigations on frictional behaviour and wear resistance of solid lubricant coatings

Yukhno, T.P.; Vvedensky, Yu.V.; Sentyurikhina, L. N.

doi:10.1016/s0301-679x(01)00013-5

Cited by 46 publications

(23 citation statements)

References 5 publications

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“…Michael et al [1], Theiler et al [2], and Hubner et al [3] compared results of ambient lab air testing with those of test submerged in cryogenic liquids and have shown either no trend or trends of reduced friction at cryogenic temperatures. Recent constant environment macroscale studies of various solid lubricants [4][5][6][7], and atomic-scale studies with terraces of graphite [8] show consistent trends of increased friction with decreased temperature, and the notion of thermally activated friction has been proposed [4,8,9]. Variable temperature experiments conducted on beds of aligned carbon nanotubes [10] and various high temperature polymer studies [11][12][13][14][15][16] have also demonstrated behavior that is well fit by an activated process at the macroscale.…”

Section: Introductionmentioning

confidence: 80%

A Possible Link Between Macroscopic Wear and Temperature Dependent Friction Behaviors of MoS2 Coatings

et al. 2008

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Studies to explore the nature of friction, and in particular thermally activated friction in macroscopic tribology, have lead to a series of experiments on thin coatings of molybdenum disulfide. Coatings of predominately molybdenum disulfide were selected for these experiments; five different coatings were used: MoS 2 /Ni, . The temperatures were varied over a range from -80°C to 180°C. The friction coefficients tended to increase with decreasing temperature. Activation energies were estimated to be between 2 and 10 kJ/mol from data fitting with an Arrhenius function. Subsequent room temperature wear rate measurements of these films under dry nitrogen conditions at ambient temperature demonstrated that the steady-state wear behavior of these coatings varied dramatically over a range of K = 7 9 10 -6 to 2 9 10 -8 mm 3 /(Nm). It was further shown that an inverse relationship between wear rate and the sensitivity of friction coefficient with temperature exists. The highest wearrate coatings showed nearly athermal friction behavior, while the most wear resistant coatings showed thermally activated behavior. Finally, it is hypothesized that thermally activated behavior in macroscopic tribology is reserved for systems with stable interfaces and ultra-low wear, and athermal behavior is characteristic to systems experiencing gross wear.

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Section: Introductionmentioning

confidence: 80%

A Possible Link Between Macroscopic Wear and Temperature Dependent Friction Behaviors of MoS2 Coatings

et al. 2008

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“…Fits of the activation energy and viscoelasticity dominated friction coefficient models appear to be acceptable quantitative descriptions of the friction coefficient behavior from 173K<T<450 K. Finally, the experimental techniques reported here are believed to address many of the concerns associated with cryotribology testing of solid lubricants, although modifications must be made for operation below T=77 K (there is a study that has successfully utilized a cold finger in vacuum to perform tribological measurements on thin films [12]). …”

Section: Closurementioning

confidence: 88%

Cryogenic Friction Behavior of PTFE based Solid Lubricant Composites

et al. 2005

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Solid lubricants used in aerospace applications must provide low friction and a predictable operation life over an extreme range of temperatures, environments and contact conditions. PTFE and PTFE composites have shown favorable tribological performance as solid lubricants. This study evaluates the effect of temperature on the friction coefficient of neat PTFE, a PTFE/ PEEK composite and an expanded PTFE (ePTFE)/epoxy coating. These experiments evaluate friction coefficient over a temperature span which, to the investigators' knowledge, has not been previously examined. Results show a monotonic increase in friction coefficient as sample surface temperature was decreased from 317 to 173 K for all three samples. The frictional performance of these and other published solid lubricant polymers was modeled using an adjusted Arrhenius equation, which correlates the coefficient of friction of the polymer materials to their viscoelastic behavior. A model fit of all the polymer data from 173 to 450 K gives an activation energy of 3.7 kJ/mol. This value suggests that breaking of van der Waals bonds is the likely mechanism responsible for the frictional behavior over this temperature range.

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“…One extreme case is shown in Figure 1. It is a sprayed MoS2 coating with polycarbamide binder, which was specially designed for space applications [7]. Figure 1a shows a scanning electron microscopy (SEM) image of the virgin coating, which consists of only loosely adhered particles.…”

Section: Introduction-lubricating Properties Of Mosmentioning

confidence: 99%

“…AF coating with polycarbamide binder [7]: (a) virgin coating; and (b) after sliding in liquid helium (LHe).…”

Section: Introduction-lubricating Properties Of Mosmentioning

confidence: 99%

Tribological Performance of MoS2 Coatings in Various Environments

Gradt

Schneider²

2016

Lubricants

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Molybdenum disulfide (MoS 2 ) is a well-known solid lubricant for tribosystems running in vacuum or dry gases. Problems arise due to its sensitivity to humidity, which is a drawback for its application under ambient conditions. However, by using a physical vapor deposition (PVD) process, deposition parameters can be optimized not only to gain a coatings structure with favorable frictional properties but also to minimize the sensitivity to attack by water molecules. Therefore, an improved tribological behavior even under moist conditions can be achieved. MoS 2 coatings are also candidates for being applied at cryogenic temperatures. They already have proven their suitability, e.g., for sliding support elements between superconducting magnets of the nuclear fusion-experiment Wendelstein 7-X. However, these coatings were exclusively produced for this particular application and the utilization for more common tribosystems may be precluded due to cost considerations. In view of a wider range of applications, pure and Cr containing PVD-MoS 2 coatings with an optimized structure were tested under varying environments including hydrogen gas and cryogenic temperatures. Results of the most promising variant are presented in this paper.

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Low temperature investigations on frictional behaviour and wear resistance of solid lubricant coatings

Cited by 46 publications

References 5 publications

A Possible Link Between Macroscopic Wear and Temperature Dependent Friction Behaviors of MoS2 Coatings

A Possible Link Between Macroscopic Wear and Temperature Dependent Friction Behaviors of MoS2 Coatings

Cryogenic Friction Behavior of PTFE based Solid Lubricant Composites

Tribological Performance of MoS2 Coatings in Various Environments

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