Boundary Film Formation by ZnDTPs and Detergents Using ECR

Yamaguchi, E. S.; Ryason, P. R.; Yeh, Sung-Wei; Hansen, T. P.

doi:10.1080/10402009808983747

Cited by 57 publications

(25 citation statements)

References 15 publications

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“…Their corresponding basic forms give rise to peak 3 (98.21 ppm) and 5 (101.14 ppm). The basic form, [(RO) 2 PS 2 ] 6 Zn 4 O can convert to the neutral form, [(RO) 2 PS 2 ] 2 Zn and ZnO at elevated temperature [48]. The peak at a shift at 76.37 ppm with a relative height of 0.0176, is caused by an impurity, and the most probable species is (RO) 2 P(S)SR or (RO) 2 P(S)OR [28].…”

Section: P Nmr Resultsmentioning

confidence: 99%

Studies on ZDDP Thermal Film Formation by XANES Spectroscopy, Atomic Force Microscopy, FIB/SEM and 31P NMR

Pereira

Lachenwitzer

et al. 2007

Tribol Lett

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X-ray absorption near edge structure (XANES) spectroscopy has been used to characterize the chemistry of thermal films on steel samples, which were generated from a mineral base oil containing a zinc dialkyl dithiophosphate (ZDDP) additive. These films were formed at 150°C by immersing steel coupons in ZDDP oil solutions. The phosphorus L-edge XANES spectra show that these films are composed of polyphosphates, unreacted ZDDP and other thiophosphate intermediates. Phosphorus K-edge FY XANES was used to monitor the thickness of these films, and the data are consistent with thickness derived by focussed ion beam (FIB) milling and SEM imaging. The sulphur K-edge TEY and FY XANES spectra show that these films are composed of different sulphur components, which depend upon the formation times. The surface morphology of these films was investigated using atomic force microscopy (AFM). These images show that the surface morphology of the thermal films changes with the formation time. 31P NMR spectra show that both primary and secondary ZDDP decomposes gradually at 150°C.

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Section: P Nmr Resultsmentioning

confidence: 99%

Studies on ZDDP Thermal Film Formation by XANES Spectroscopy, Atomic Force Microscopy, FIB/SEM and 31P NMR

Pereira

Lachenwitzer

et al. 2007

Tribol Lett

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“…Many advanced spectroscopic techniques have been applied to elucidate the chemical nature of tribofilms generated from antiwear agents. X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) [1][2][3][4][5], reflectance infrared spectroscopy [5][6][7][8][9] and X-ray absorption near edge structure (XANES) spectroscopy [10][11][12][13][14][15][16][17][18] have played a major role to understand the mechanisms of formation of antiwear film on the rubbed surfaces. A good summary of the role of many of these techniques is given in a very recent paper [10].…”

Section: Introductionmentioning

confidence: 99%

Tribofilms generated from ZDDP and DDP on steel surfaces: Part 2, chemistry

et al. 2005

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The chemical constitution of tribofilms, generated from zinc dialkyldithiophosphate (ZDDP) and ashless dialkyldithiophosphate (DDP), has been examined by X-ray Absorption Near Edge Structure (XANES) spectroscopy. The identification of spectral features and interpretation of the results for P, O, Fe, and S species are given, allowing an overall mechanism to be deduced. The role of Fe in these films was investigated in some detail using P L-edge, O K-edge and Fe L-edge XANES spectra. From the P L-edge XANES spectra, the DDP films are uniformly very short chain iron polyphosphates. In contrast, the ZDDP films are formed initially as short chain polyphosphates; but after more rubbing, a bilayer phosphate film is formed with long chain Zn polyphosphates on the surface and shorter chain in the bulk of the film. The O K-edge XANES spectra show that there is, as expected, more Fe in the DDP phosphate films than in the ZDDP phosphate films. The S K-edge spectra of ZDDP films show the presence not only of ZnS as previously observed, but also the presence of FeS for the first time in the early stages of film formation. The predominant S species in the DDP films is FeS.

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“…We have also reported on the ECR measurements on two different ferrous tribocouples sliding in oils containing commercial ZDDPs of different types (primary, secondary, and aryl) [10]. In addition, we have studied the wear performance and ECR behavior of ZDDPs in the presence of detergents [11]. All these types of additives are present in modern passenger car oils, such as the ones tested for this work.…”

Section: Resultsmentioning

confidence: 99%

Comparison of a 2-Dimensional Wear Scar Measurement and a 3-Dimensional Profilometer Measurement of the Same Wear Scar in a Point Contact

Yamaguchi¹,

Li²,

Ng³

2012

Tribology Online

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In a tribological experiment, one relies on the ability to measure accurately the wear scar in the contact. Usually, in a point contact, the wear scar diameter (WSD) is measured, and measurements of this kind may be compared for several different oils, for example. This type of experiment might be carried out on a ball-on-disk tribometer with a point contact, where the disk measurement might be considered of secondary importance. In a recent study, it was advantageous to measure the wear scar width (WSW) of the disk wear scar, which led to the question of whether the relative rankings provided by the WSWs would correspond to the more tedious profilometry that is often carried out in various tribological investigations. In this study of modern passenger car oils, we make that comparison and show that there is a 1-to-1 correspondence between the WSW determinations by optical microscope (OM) and the profilometry studies. These studies were carried out using the versatile and modified MTM™ tribometer.

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Boundary Film Formation by ZnDTPs and Detergents Using ECR

Cited by 57 publications

References 15 publications

Studies on ZDDP Thermal Film Formation by XANES Spectroscopy, Atomic Force Microscopy, FIB/SEM and 31P NMR

Studies on ZDDP Thermal Film Formation by XANES Spectroscopy, Atomic Force Microscopy, FIB/SEM and 31P NMR

Tribofilms generated from ZDDP and DDP on steel surfaces: Part 2, chemistry

Comparison of a 2-Dimensional Wear Scar Measurement and a 3-Dimensional Profilometer Measurement of the Same Wear Scar in a Point Contact

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