The Reaction of Perfluoropolyalkylether Oil with FeF3, AlF3, and AlCl3at Elevated Temperatures

Carre, D. J.; Markowitz, Jonathan A.

doi:10.1080/05698198508981592

Cited by 67 publications

(11 citation statements)

References 19 publications

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“…Broad bands in the 3600-3000, 1669, and 1436 cm 21 areas of Fig. 7 correlate well with other literature studies of polymeric fluorinated carboxylic acids (Carré and Markowitz 1985;Eapen et al 1994;Xuan et al 1993). The presence of a strong broad band at 3600-3000 cm 21 suggests that some of the adsorbed carboxylate is hydrogen-bonded.…”

Section: Postmortem Analysis Of Space Lubricants-fundamental Investigsupporting

confidence: 77%

“…The spectroscopic evidence led to the proposed degradation pathway for all PFPE involving defluorination, chain scission, and formation of carbonyl end groups as suggested in prior literature (Carré 1985;Eapen et al 1994;Xuan et al 1993). Carboxylic acid groups form quickly when carbonyl groups react with humidity in the air, and in turn react with surface metal ion species to form carboxylates.…”

Section: Postmortem Analysis Of Space Lubricants-fundamental Investigmentioning

confidence: 88%

“…These corrosive products attack the metal bearing parts to produce metal fluorides, which themselves are soft and lubricious but ironically serve as catalysts to accelerate further decomposition (Carré 1985;Eapen et al 1994). In the preceding section additives were employed in attempts to react with the surface and prevent the degradation reaction.…”

mentioning

confidence: 99%

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Liquid Space Lubricants Examined by Vibrational Microspectroscopy

Street

2008

Analytical Letters

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Considerable effort has been expended to develop liquid lubricants for satellites and space exploration vehicles. These lubricants must often perform under a range of harsh conditions such as vacuum, radiation, and temperature extremes while in orbit or in transit and in extremely dusty environments at destinations such as the moon and Mars. Historically, oil development was guided by terrestrial application, which did not provide sufficient space lubricants. Novel fluids such as perfluorinated polyethers provided some relief but are far from ideal. With each new fluid proposed to solve one problem, other problems have arisen. Much of the work performed at National Aeronautics and Space Adminstration's (NASA) Glenn Research Center, in elucidating mechanisms by which chemical degradation of space oils occur, has been done by infrared and Raman microspectroscopy, which this review details. Fundamental lubrication studies are presented as well as actual case studies, in which vibrational spectroscopy led to millions of dollars in savings and potentially prevented loss of mission.

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Section: Postmortem Analysis Of Space Lubricants-fundamental Investigsupporting

confidence: 77%

Section: Postmortem Analysis Of Space Lubricants-fundamental Investigmentioning

confidence: 88%

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Liquid Space Lubricants Examined by Vibrational Microspectroscopy

Street

2008

Analytical Letters

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“…The hydrolysis of iron fluorides yields iron hydroxides and iron oxides and hence results in the rusting of iron. Iron fluorides are one of the Lewis acids that catalyze the degradation of lubricants [29,32]. Therefore, a decrease in the tribochemical reaction of the TFSA anion appears to be instrumental in improving the tribological properties of RT-ILs.…”

Section: Lubrication Mechanismmentioning

confidence: 99%

Tribo-Chemistry of Phosphonium-Derived Ionic Liquids

et al. 2010

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The tribological properties of room temperature ionic liquids containing tetraalkylphosphonium cations were evaluated on the basis of the chemical structure of their salts. The tribochemistry of these ionic liquids was discussed on the basis of the results of tribo-tests and surface analyses. The tribological properties of the tetraalkylphosphonium salts examined in this work were observed to be better than those of 1,3-alkylimidazolium salts. The structure of the alkyl group in the phosphonium cation also has a slight effect on the tribological properties of the salts. During a friction test carried out under lowload conditions, the phosphonium cation was oxidized to phosphate to form a boundary film. This film inhibited the reaction of the bis(trifluoromethanesulfonyl)amide anion that yielded metal fluoride on the rubbed surfaces. The combination of the phosphonium cation with a phosphate anion or thiophosphate anion resulted in a better lubricant than 1,3-alkylimidazolium bis(trifluoromethanesulfonyl)amide. The reactions of the phosphate anion and thiophosphate anion yielded a phosphate boundary film that exhibited better tribological properties than those of the fluoride boundary film.

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“…Research has repeatedly shown that PFPE's degrade while in boundary-lubricated,sliding/rolling contacts (5)(6)(7)(8)(9)(10) and at elevated temperatures (11)(12)(13)(14) losing their desirable properties, including lubricity.Although few models have been proposed to explain the observed degradation, it has been shown that the rate of degradation, under static, elevated temperature conditions, is dependent upon the surface chemistry of the substrate and relative strength of the Lewis acid substrates. Kasai (11) has shown that the thermal catalytic degradation of a PFPE depends upon the strength of the Lewis acid substrate present, and has proposed a chemical degradation mechanism for each of the four commercial PFPE's.…”

Section: Introductionmentioning

confidence: 99%