Study of interaction of EP and AW additives with dispersants using XANES

Zhang, Z.; Najman, M.N.; Kasrai, M.; Bancroft, G.M.; Yamaguchi, E. S.

doi:10.1007/s11249-004-1748-9

Cited by 53 publications

(41 citation statements)

References 21 publications

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“…A similar effect is found with tributyl phosphite [24]. While the chemical nature of the phosphorus cannot be measured using Auger spectroscopy, NEXAFS analyses of the tribological films formed from phosphorus-containing additives reveal the formation of phosphates [33][34][35][36][37]. At higher phosphorus concentrations and temperatures, the phosphates polymerize to form relatively hard polyphosphate glasses.…”

Section: Discussionmentioning

confidence: 69%

Reaction of tributyl phosphate with oxidized iron: surface chemistry and tribological significance

et al. 2005

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The chemistry of tributyl phosphate on Fe 3 O 4 was studied in ultrahigh vacuum using temperature-programmed desorption (TPD) and Auger spectroscopy. A portion of the tributyl phosphate desorbs intact with an activation energy of $120 kJ/mol. The remainder decomposes either by PAO bond scission to deposit surface butoxy species or appears to dehydrogenate desorbing C 2 or C 3 compounds and depositing hydrogen and carbon on the surface. The resulting hydrogen reacts either with the oxide to desorb water or with butoxy species yielding 1-butanol. The remaining butoxy species are stable up to $600 K where they decompose to desorb butanal via hydride elimination where again the hydrogen reacts with butoxy species to form 1-butanol or with the oxide to form water. The carbon deposited onto the surface further reduces the oxide to desorb as CO above $750 K, although a small amount of carbon is detected on the surface using Auger spectroscopy. Substantially larger amounts of carbon are deposited onto the surface when Fe 3 O 4 is exposed to tributyl phosphate at 300 K, where an Auger depth profile reveals that the carbon is located at the surface while the PO x species formed by tributyl phosphate decomposition diffuse rapidly into the oxide layer, leading to a film structure in which graphitic carbon is deposited onto a phosphorus-containing oxide layer.

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Section: Discussionmentioning

confidence: 69%

Reaction of tributyl phosphate with oxidized iron: surface chemistry and tribological significance

et al. 2005

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“…6(a), and the spectral data are listed in Table 1 spectrum correspond to iron sulfide, alkylsulfur, [28] sulfite and sulfate, respectively. It can be seen that temperature has some influence on the components of tribofilms.…”

Section: Xanes Spectroscopy Of Tribofilms At Different Temperaturesmentioning

confidence: 99%

“…[25,28], and the alkyldisulfide comes from the decomposition of the additive molecule. Peak c situated at 2477.0 eV corresponds to sulfite, and peak d situated at 2482.1 eV corresponds to sulfate.…”

Section: S and P K-edge Xanes Spectra Of Thermal Filmsmentioning

confidence: 99%

XANES characteristics of tribofilms generated by dithiophosphate additive in water at different test temperatures and durations

Qiao

et al. 2009

Surface & Interface Analysis

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Water-based lubricants and metal-working fluids are becoming more and more popular in modern manufacturing due to environmental concerns. Owing to the poor lubricating properties offered by pure water, additives are generally needed to improve the antiwear and extreme pressure properties. In the present work, the tribological behaviors of synthesized additives in water-based lubricants are studied for different durations and temperatures by a four-ball machine, and the worn surfaces were analyzed by scanning electron microscopy (SEM) and X-ray absorption near-edge structure (XANES) spectroscopy. It was found that the tribological properties changed with the duration and temperature, and the tribofilms mainly consisted of an adsorbed layer and a tribochemical layer. The compositions of tribofilms also changed with duration and temperature, and the different compositions of tribofilms would result in different tribological properties accordingly.

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“…Since its first application in 1989, many papers based on the application of XANES to study ZDDP films have been published [8][9][10][11][12][13][14][15][16]. The interaction of ZDDP with detergents or dispersant has also been investigated widely by many studiers [9,[17][18][19]. Yin et al [9] found that the polyphosphate films formed in the presence of the detergents and dispersants have shorter-chain length compared with ZDDP alone and contain less unchanged ZDDP.…”

Section: Introductionmentioning

confidence: 99%

“…Yin et al [9] found that the polyphosphate films formed in the presence of the detergents and dispersants have shorter-chain length compared with ZDDP alone and contain less unchanged ZDDP. Zhang et al [17][18][19] found that the borated dispersant facilitates the decomposition of ZDDP and the formation of phosphate in tribofilms and thermal films.…”

Section: Introductionmentioning

confidence: 99%

The Tribological Chemistry of the Oil Blends of Zinc Dialkyldithiophosphate with 2-Mercaptobenzothiazole Derivatives

Ren

Zuo

2009

Tribol Lett

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X-ray absorption near-edge spectroscopy at the phosphorous and sulfur edges was used to identify the chemical species in thermal films and antiwear films on the macroscale. For the thermal films, it was found that the introduction of the additive MBTT/MBTA to the base oil, zinc dialkyldithiophosphate (ZDDP), tended to retard the formation of the polyphosphate, and has no effect on the thickness of the films. The topmost surface thermal films may be mainly comprised of some new compounds generated from the interaction of ZDDP with the antiwear additives MBTT/MBTA, along with a small amount of unchanged ZDDP, the sub-surface, and the bulk were mainly comprised of Zn phosphate, along with an amount of ZnS. For the antiwear films, the introduction of the additive MBTT/MBTA to the base oil, ZDDP, reduces the chain length of polyphosphate, which the N-containing decomposed products of 2-mercaptobenzothiazole derivatives are responsible for. It is very clear that MBTT or MBTA has indeed interacted with ZDDP to form new phosphate in the overall antiwear films. The topmost surface antiwear films were mainly comprised of short-chain polyphosphate, the sub-surface and the bulk may be mainly comprised of Zn phosphate and ZnS.

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Study of interaction of EP and AW additives with dispersants using XANES

Cited by 53 publications

References 21 publications

Reaction of tributyl phosphate with oxidized iron: surface chemistry and tribological significance

Reaction of tributyl phosphate with oxidized iron: surface chemistry and tribological significance

XANES characteristics of tribofilms generated by dithiophosphate additive in water at different test temperatures and durations

The Tribological Chemistry of the Oil Blends of Zinc Dialkyldithiophosphate with 2-Mercaptobenzothiazole Derivatives

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