Investigating binary oil additive systems containing P and S using X-ray absorption near-edge structure spectroscopy

Najman, M.N.; Kasrai, M.; Bancroft, G.M.

doi:10.1016/s0043-1648(03)00537-4

Cited by 40 publications

(40 citation statements)

References 16 publications

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“…For energy scale calibration at O K-edge FePO 4 was used at 530.8 eV. The calibration at other edges has been reported before [16,17].…”

Section: Xanes Data Analysesmentioning

confidence: 99%

“…We have shown in previous papers that the intensity of the P K-edge XANES spectra can be used to measure the average thickness of the major phosphate component of ZDDP-derived antiwear films and thermal films [15][16][17]. The measured P K-edge peak heights and edge jumps from the XANES spectra measured in the FY mode were initially plotted against the particle induced X-ray emission (PIXE) results, yielding calibration curves (figure 2 in Ref.…”

Section: Film Thicknessmentioning

confidence: 99%

“…Techniques such as Electron-Probe Micro-Analysis (EPMA) [5,9], Secondary Electron Microscopy with Energy Dispersive X-ray Analysis (SEM/EDX) [1,12,13], Particle Induced X-ray Emission (PIXE) [14] and X-ray Absorption Near Edge Structure (XANES) Spectroscopy [15][16][17] are more desirable in that they are nondestructive. These techniques yield a mass film thickness, and provided that the film density is known, a physical thickness can be calculated.…”

Section: Introductionmentioning

confidence: 99%

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Tribofilms generated from ZDDP and DDP on steel surfaces: Part 1, growth, wear and morphology

et al. 2005

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The growth and morphology of tribofilms, generated from zinc dialkyldithiophosphate (ZDDP) and an ashless dialkyldithiophosphate (DDP) over a wide range of rubbing times (10 s to 10 h) and concentrations (0.1-5 wt% ZDDP), have been examined using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge structure (XANES) spectroscopy at the O, P and S K-edges and the P, S, and Fe L-edges. The physical aspects of the growth and morphology of the tribofilms will be presented in Part I and the chemistry of the films will be discussed in Part II. The major components of all films on 52100 steel are Zn and Fe phosphates and polyphosphates. The average thickness of these phosphate films has been measured using P K-edge XANES and XPS profiling. For ZDDP, a very significant phosphate film (about 100 Å thick) forms after 10 s, while film development for DDP is substantially slower. However, for both additives, the average film thickness increases to 600-800 Å after 30 min of rubbing, before leveling off or decreasing. The antiwear properties of pure ZDDP and in combination with DDP at different rubbing times and concentrations have also been examined. It was found that under all conditions, the performance of ZDDP as an antiwear agent is superior to that of DDP. However, DDP has no adverse effect on the performance of ZDDP when the two are mixed. The AFM results show that ZDDP forms larger and better developed ''pads'' than DDP at short rubbing times. At longer rubbing times, both films become more uniform. For the 1 h ZDDP films, the film thickness is surprisingly independent of the ZDDP concentration from 0.1 to 5 wt% ZDDP. The film thickness is also independent of the ratio of ZDDP/DDP concentrations.

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“…For energy scale calibration at O K-edge FePO 4 was used at 530.8 eV. The calibration at other edges has been reported before [16,17].…”

Section: Xanes Data Analysesmentioning

confidence: 99%

Section: Film Thicknessmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Tribofilms generated from ZDDP and DDP on steel surfaces: Part 1, growth, wear and morphology

et al. 2005

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“…metal-free) additives, such as organosulfur compounds [6], phosphates [6][7][8][9][10][11][12][13][14][15][16], amine phosphates [12], phosphites [11,[17][18][19], phosphorothionates [12][13][14][20][21][22][23][24][25][26], and dithiophosphates [12,21,22,24].…”

Section: Introductionmentioning

confidence: 99%

“…Several analytical techniques have been employed to characterize the reaction layers, such as X-ray photoelectron spectroscopy (XPS) [7,12,14,25,26], X-ray absorption spectroscopy (XAS) [13,[21][22][23][24], X-ray photoelectron emission microscopy (X-PEEM) [24], scanning electron microscopy (SEM) [20,21], Fourier transform infrared spectroscopy (FT-IR) [7,14,16], Auger electron spectroscopy (AES) [8-10, 14, 17, 18], and atomic force microscopy (AFM) [22]. Najman et al investigated the thermal films and tribofilms formed by phenyl phosphates on steel [13].…”

Section: Introductionmentioning

confidence: 99%

Reactivity of Triphenyl Phosphorothionate in Lubricant Oil Solution

2009

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Investigating the thermo-oxidative reactivity of anti-wear additives in lubricant oil solution at high temperature can significantly contribute to an understanding of the mechanism of thermal film and tribofilm formation on metal surfaces. In this study, the reactivity of triphenyl phosphorothionate (TPPT) in lubricant oil solution at high temperature (423 and 473 K) has been studied by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy. The results show that the TPPT molecule was highly thermally stable and did not completely decompose in oil solution even upon heating at 423 K for 168 h and at 473 K for 72 h. The degradation of the TPPT molecule, which turned out to be a first-order reaction, started taking place after 6 h at both temperatures, leading to the breakage of the P=S bond with the formation of triphenyl phosphate. During these heating experiments, no oil-insoluble compounds were detected. The oxidation of the base oil as a result of the prolonged heating demonstrated that the TPPT molecule did not effectively act as oxidation inhibitor.

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Chemical and physical properties of tribofilms formed by the interaction of ashless dithiophosphate anti‐wear additives

Vyavhare

Bagi

Pichumani

et al. 2021

Lubrication Science

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Physiochemical properties of tribofilms generated from octadecylthioperoxydiphosphate (SSC18) and octadecylphosphorofluoridothioate (PFC18) were compared with zinc dialkyl dithiophosphates (ZDDP) in this study. PFC18 and SSC18 were chemically synthesised and mixed in mineral base oil to prepare test oil formulations. Additionally, PFC18 and SSC18 were mixed at different concentrations and evaluated for their compatibility and tribological performance using high frequency reciprocating rig (HFRR) tribometer. All lubricant formulations with ashless additives exhibited superior anti-wear characteristics compared to ZDDP. Comprehensive surface analysis of tribofilms was conducted using scanning electron microscopy, nano-indentation and X-ray absorption near edge spectroscopy. Formulations containing only SSC18 and PFC18 exhibited a uniform and continuous tribofilm formation, while formulations with a combination of SSC18 and PFC18 had a stable pad-like structure. X-ray absorption near edge structure (XANES) results indicate ashless PFC18 and SSC18 by themselves and in combination form iron phosphate enriched tribofilms with a mixture of iron sulfides and/or sulfates.

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Investigating binary oil additive systems containing P and S using X-ray absorption near-edge structure spectroscopy

Cited by 40 publications

References 16 publications

Tribofilms generated from ZDDP and DDP on steel surfaces: Part 1, growth, wear and morphology

Tribofilms generated from ZDDP and DDP on steel surfaces: Part 1, growth, wear and morphology

Reactivity of Triphenyl Phosphorothionate in Lubricant Oil Solution

Chemical and physical properties of tribofilms formed by the interaction of ashless dithiophosphate anti‐wear additives

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