Comparative Study of the Tribological and Oxidative Properties of AlPdMn Quasicrystals and Their Cubic Approximants

Mancinelli, Chris; Ko, Jeff S.; Jenks, Cynthia J.; Thiel, Patricia A.; Ross, A. R.; Lograsso, Thomas A.; Gellman, Andrew J.

doi:10.1557/proc-643-k8.2

Cited by 8 publications

(13 citation statements)

References 22 publications

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“…Until now, most experimental studies of tribology on quasicrystals [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] have been carried out under conditions in which irreversible ͑plastic͒ deformation takes place during sliding. Frictional energy dissipation measured under such conditions includes contributions from such diverse factors as the breaking of chemical bonds, generation of point defects, interactions with wear debris, phase transformations near the sliding track, and in crystalline materials by creation of dislocations and propagation of slip planes in specific crystallographic directions.…”

Section: Introductionmentioning

confidence: 99%

“…A set of studies in ultrahigh vacuum has been reported by Gellman et al, 8,10,11 who found that the friction coefficient of clean, single-grain quasicrystalline Al-Pd-Mn is half that of a crystalline Al-Pd-Mn alloy with similar stoichiometry. However, they found no variation in friction coefficient across a series of quasicrystalline-related phases in the Al-Cu-Fe family, leading them to suggest that friction is not related to atomic structure.…”

Section: Introductionmentioning

confidence: 99%

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Tribological properties of quasicrystals: Effect of aperiodic versus periodic surface order

et al. 2006

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We investigated the nanoscale tribological properties of a decagonal quasicrystal using a combination of atomic force microscopy and scanning tunneling microscopy in ultrahigh vacuum. This combination permitted a variety of in situ measurements, including atomic-scale structure, friction and adhesion force, tipsample current, and topography. We found that thiol-passivated tips can be used for reproducible studies of the tip-quasicrystal contact while nonpassivated probes adhere irreversibly to the clean quasicrystalline surface causing permanent modifications. The most remarkable results were obtained on the twofold surface of the Al-Ni-Co decagonal quasicrystal where atoms are arranged periodically along the tenfold axis and aperiodically in the perpendicular direction. Strong friction anisotropy was observed on this surface, with high friction along the periodic direction and low friction in the aperiodic direction. We investigated the nanoscale tribological properties of a decagonal quasicrystal using a combination of atomic force microscopy and scanning tunneling microscopy in ultrahigh vacuum. This combination permitted a variety of in situ measurements, including atomic-scale structure, friction and adhesion force, tip-sample current, and topography. We found that thiol-passivated tips can be used for reproducible studies of the tip-quasicrystal contact while nonpassivated probes adhere irreversibly to the clean quasicrystalline surface causing permanent modifications. The most remarkable results were obtained on the twofold surface of the Al-Ni-Co decagonal quasicrystal where atoms are arranged periodically along the tenfold axis and aperiodically in the perpendicular direction. Strong friction anisotropy was observed on this surface, with high friction along the periodic direction and low friction in the aperiodic direction.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Tribological properties of quasicrystals: Effect of aperiodic versus periodic surface order

et al. 2006

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“…The very first steps of the oxidation of quasicrystals based on aluminum [4][5][6][7][8][9][10][11][12][13] and the effect of oxygen on thin films formation [14,15] have been the subject of many studies. In particular, for i-AlCuFe, two temperature regimes were pointed out for the oxidation mechanism of the surface by pure oxygen, each preceded by a chemisorption step.…”

Section: Introductionmentioning

confidence: 99%

Oxidation kinetics of the quasicrystalline i-AlCuFe phase compared with that of crystalline ω-AlCuFe and pure aluminum

Rouxel¹,

Gil-Gavatz²,

Pigeat³

et al. 2005

Journal of Non-Crystalline Solids

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“…AES shows that exposure to O 2 results in the formation of a thin film of aluminum oxide that passivates the surface against further oxidation. This is similar to the oxidation of the surface of aluminum itself [ 101,102]. These films have an influence on the frictional properties of the surface.…”

Section: Tribology Of Quasicrystalsmentioning

confidence: 74%

Surface chemistry in tribology

Gellman

Spencer²

2002

Proceedings of the Institution of Mechanical Engineers, Part J:

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IntroductionIn general, the twentieth century marked the first major incursion of chemists into the world of tribology. Driven partly by the need for improved lubricants for new machines developed in the first few decades of the century, and partly by new analytical capabilities, lubricant chemists and tribochemists were to become full partners in the science of tribology. In this review we cover a number of topics in surface chemistry in tribology, which serve both to illustrate some of the successes in tribochemical research over the past decades, and also to show that much work remains to be done before true, first-principles tribochemistry-based lubricant and tribopair design can begin. Boundary Lubrication and Oiliness AdditivesIn an ideal world, lubricated sliding surfaces are separated by a stable fluid film of lubricant, which effectively lowers friction and prevents wear, holding the surfaces apart by virtue of its fluid-mechanical properties. The friction coefficient in such a hydrodynamically lubricated bearing is proportional to ηU/W, where U is the relative sliding speed of the surfaces, W the normal load supported by the bearing and η the Newtonian viscosity [1]. At low sliding speeds (e.g upon startup) and/or higher forces, however, the friction coefficient varies in a more complex way (Figure 1) and at the lowest speeds and friction forces can be 2 orders of magnitude higher than under hydrodynamic lubrication conditions. This is the regime of "boundary lubrication", where fluid films have given way to thin layers that serve as the active lubricants, and the realm of pure engineering (hydrodynamic lubrication) has given 2 way to the complex world of surface chemistry under confinement. Boundary lubrication is clearly of vital importance, since it is the mechanism in operation under the most extreme of tribological conditions. Understanding boundary lubrication, however, has been a challenge to tribochemists over the last century, with light appearing at the end of the tunnel only quite recently. Monolayers, Multilayers and soapsIt was noticed in the 1920s that certain lubricants possessed a quality designated "oiliness", which, independent of their viscosity, led to better lubrication at low sliding speeds [2][3][4]. Generally, these oily lubricants tended to be those of natural origin, such as castor oil, containing long-chain oxygenated organic compounds (esters and acids), which have surfactant properties, and are not usually present in their mineral oil counterparts. It was shown that these oxygenated molecules could, by themselves, reduce friction considerably between sliding surfaces, their effectiveness depending on their molecular weight [5] (Figure 2). Hardy developed a monolayer theory of boundary lubrication (Figure 3), whereby he postulated that, under boundary conditions, the sliding surfaces were held apart by adsorbed, oriented monolayers of polar molecules, which form a plane of low shear strength, thus lowering friction and affording protection of the surfaces.3 Figure 2. Depe...

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Comparative Study of the Tribological and Oxidative Properties of AlPdMn Quasicrystals and Their Cubic Approximants

Cited by 8 publications

References 22 publications

Tribological properties of quasicrystals: Effect of aperiodic versus periodic surface order

Tribological properties of quasicrystals: Effect of aperiodic versus periodic surface order

Oxidation kinetics of the quasicrystalline i-AlCuFe phase compared with that of crystalline ω-AlCuFe and pure aluminum

Surface chemistry in tribology

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