The Decomposition Mechanism of Perfluoropolyether Lubricants during Wear

Vurens, G.H.; Zehringer, R.; Saperstein, David D.

doi:10.1021/bk-1992-0485.ch010

Cited by 35 publications

(19 citation statements)

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“…However, there is still enough water absorbed on the walls of the vacuum chamber to have chance to form a significant amount of OH by reaction with the fluorinated products. Many investigators have confirmed existence of enough water in vacuum system [34]. The band at 1663 cm -1 can be caused by telescopic motion of the carboxylic acid with carbonyl groups (C=O) [35].…”

Section: Friction and Wear Behaviourmentioning

confidence: 99%

The Effect of Plasma Nitriding on the Tribology of Perfluoropolyether Grease-Lubricated 2Cr13 Steel Couples in Vacuum

Yang

Liu

et al. 2010

Tribol Lett

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A 2Cr13 steel was modified by plasma nitriding. The microstructure, phase composition and microhardness of the nitrided samples were examined. The friction and wear behaviour of the nitrided and unnitrided samples sliding against self-mating under PFPE grease-lubricated conditions in vacuum was investigated on a pin-on-disk type tribometer, with the interactions among the nitrided layer and grease to be focused on. The morphologies of the worn surfaces were observed using a scanning electron microscope. The chemical states of several typical elements on the worn surfaces were examined by means of X-ray photoelectron spectroscopy. The chemical compositions of grease samples taken from the worn surfaces were analyzed by Fourier transform infrared spectroscopy (FTIR). Results show that the nitrided steel has better friction-reducing and anti-wear abilities than the unnitrided one under PFPE grease-lubricated conditions. In the former case, the wear of nitrided steel shows a transition from mild abrasive wear to fatigue one with increasing normal load. In the latter case, wear mechanism of unnitrided steel under all load applied is a combination of the severe abrasion and fatigue.

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Section: Friction and Wear Behaviourmentioning

confidence: 99%

The Effect of Plasma Nitriding on the Tribology of Perfluoropolyether Grease-Lubricated 2Cr13 Steel Couples in Vacuum

Yang

Liu

et al. 2010

Tribol Lett

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“…Many experiments demonstrate that PFPEs, subjected to electron irradiation, are easily decomposed into smaller fragments [19]. Vureus et al [20] used low energy electrons to bombard PFPEs and observed that the electron decomposition of PFPEs occurs at an energy below their ionization potential (about 14 eV). It is well known that, in the presence of metal and metal oxide, the rapid degradation of PFPEs takes place at temperatures below their decomposition temperatures [21,22].…”

Section: Introductionmentioning

confidence: 99%

Study of the Thermal Decomposition of PFPEs Lubricants on a Thin DLC Film Using Finitely Extensible Nonlinear Elastic Potential Based Molecular Dynamics Simulation

Nath

Wong

2014

Journal of Nanotechnology

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Perfluoropolyethers (PFPEs) are widely used as hard disk lubricants for protecting carbon overcoat reducing friction between the hard disk interface and the head during the movement of head during reading and writing data in the hard disk. Due to temperature rise of PFPE Zdol lubricant molecules on a DLC surface, how polar end groups are detached from lubricant molecules during coating is described considering the effect of temperatures on the bond/break density of PFPE Zdol using the coarse-grained bead spring model based on finitely extensible nonlinear elastic potential. As PFPE Z contains no polar end groups, effects of temperature on the bond/break density (number of broken bonds/total number of bonds) are not so significant like PFPE Zdol. Effects of temperature on the bond/break density of PFPE Z on DLC surface are also discussed with the help of graphical results. How bond/break phenomenonaffects the end bead density of PFPE Z and PFPE Zdol on DLC surface is discussed elaborately. How the overall bond length of PFPE Zdol increases with the increase of temperature which is responsible for its decomposition is discussed with the help of graphical results. At HAMR condition, as PFPE Z and PFPE Zdol are not suitable lubricant on a hard disk surface, it needs more investigations to obtain suitable lubricant. We study the effect of breaking of bonds of nonfunctional lubricant PFPE Z, functional lubricants such as PFPE Zdol and PFPE Ztetrao, and multidented functional lubricants such as ARJ-DS, ARJ-DD, and OHJ-DS on a DLC substrate with the increase of temperature when heating of all of the lubricants on a DLC substrate is carried out isothermally using the coarse-grained bead spring model by molecular dynamics simulations and suitable lubricant is selected which is suitable on a DLC substrate at high temperature.

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“…In other systems, triboelectrons can be more important to oil degradation processes. For instance, systems with insulator-on-insulator contacts (producing more and higher energy triboelectrons), and lubricated by oils that are more susceptible to electroninduced reactions (such as fluorocarbons) can have significant triboelectronic contributions to oil degradation [2,3].…”

Section: Production Of Triboelectronsmentioning

confidence: 99%

“…In addition, triboelectrons, which are sometimes called exoelectrons, can be produced during scratching of some materials [1]. There have been some studies indicating triboelectronic degradation in fluorocarbon oils [2,3], but a new class of spacecraft lubricants, the synthetic hydrocarbons called multiply alkylated cyclopentanes (MAC), have not been examined for their susceptibility to this form of degradation.…”

Section: Introductionmentioning

confidence: 99%

Low-Energy-Electron-Stimulated Degradation of a Multiply Alkylated Cyclopentane Oil and Implications for Space Bearings

Bertrand

2010

Tribol Lett

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The volatile and liquid-phase products of low-energy electron irradiation of a multiply alkylated cyclopentane oil in vacuum were analyzed using mass spectroscopy, infrared spectroscopy, supercritical fluid chromatography, and gel-permeation chromatography. Both alkanes and alkenes are formed in each phase; in the fluid both primary and trans-alkenes are detected. Smaller and larger molecules than are present in the original oil (product molecular weights up to at least 10,000 g/mol) are found, and alkenes are present over the entire molecular weight range. The dependence of the amount of products found on electron beam energy and current suggest that the first step of the process is fragmentation of the oil molecules and their initial transformation into both volatile and non-volatile alkenes and alkanes, followed by further reaction to form larger molecules. Combining these results with an estimate of the properties of the triboelectrons that would probably be produced during wear in either all-steel or hybrid (steel raceways with ceramic balls) ball bearings in spacecraft, we find that degradation in vacuum due to triboelectronic reactions alone, with this type of lubricant in this application, is insignificant. Oil degradation in these systems in vacuum is likely due to chemical reactions with fresh metal surfaces produced during wear.

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The Decomposition Mechanism of Perfluoropolyether Lubricants during Wear

Cited by 35 publications

References 0 publications

The Effect of Plasma Nitriding on the Tribology of Perfluoropolyether Grease-Lubricated 2Cr13 Steel Couples in Vacuum

The Effect of Plasma Nitriding on the Tribology of Perfluoropolyether Grease-Lubricated 2Cr13 Steel Couples in Vacuum

Study of the Thermal Decomposition of PFPEs Lubricants on a Thin DLC Film Using Finitely Extensible Nonlinear Elastic Potential Based Molecular Dynamics Simulation

Low-Energy-Electron-Stimulated Degradation of a Multiply Alkylated Cyclopentane Oil and Implications for Space Bearings

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