Zinc content of ZDDP films formed thermally and mechanically

Hershberger, J.; Ajayi, O. O.; Fenske, G.R.

doi:10.1016/j.triboint.2004.08.013

Cited by 7 publications

(6 citation statements)

References 12 publications

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“…Our results provide evidence that un-reacted ZDDP (which aligns with peak 2 (figure 1)) decreases significantly when the concentration of ZDDP is decreased from 1.2 to 0.3%. Current U.S. environmental laws regulate maximum P content in passenger vehicles to 0.1%, resulting in a ZDDP concentration of $1% [18], which has also been found to be close to the optimum ZDDP concentration range for the AW regime [55]. Chao et al [55] has suggested that increasing ZDDP concentrations promote thicker films, which are also formed more rapidly.…”

Section: Total Electron Yieldmentioning

confidence: 90%

“…Recently, Hershberger et al [18] using very high-ZDDP concentrations has provided insight about the role of the Zn cation in the formation of polyphosphate glasses. It was shown that with X-ray fluorescence that the Zn atom concentrations in the thermal films are distinctly higher than for tribologically prepared samples, and furthermore an atomic concentration threshold was found for the Zn atoms in the films based upon the ZDDP concentration.…”

Section: Introductionmentioning

confidence: 99%

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A multi-technique characterization of ZDDP antiwear films formed on Al (Si) alloy (A383) under various conditions

et al. 2007

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The simulation of the lubrication of aluminum-silicon (Al-Si) alloy cylinder-bore conditions is an important goal in automotive tribology. This study describes the use of X-ray absorption near edge structure (XANES) to determine the macro-chemistry of zinc-dialkyl-dithiophosphates (ZDDPs) antiwear (AW) films formed on A383, an Al-Si alloy. The temperature dependence of the chemistry and mechanical properties were examined using X-ray photoelectron emission microscopy (X-PEEM), and imaging indentation techniques. Our findings suggest that ZDDPs break down to form polyphosphate glasses, which have different chemical natures and depend on the underlying substrate. Furthermore, the chemical nature of the films appears temperature dependent on both the macro-and micro-scale. Not only are the chemical species different, but the mechanical properties also differ, depending on the region upon which an AW pad is formed. Through the use of focused ion beam (FIB) milling, we can determine the film thickness, which was previously estimated from the P K-edge XANES areal density of samples with known thicknesses.

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Section: Total Electron Yieldmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

A multi-technique characterization of ZDDP antiwear films formed on Al (Si) alloy (A383) under various conditions

et al. 2007

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“…The requirements of the automobile industry have pressured lubricant manufacturers to try to find replacements for ZDDPs, so far with little success, as it has been found economically impossible to find any reasonable additive having comparable antiwear performance to ZDDPs in fully formulated engine oils. To add to the replacement challenge, under the current United States Environmental Protection Agency (EPA) regulations, the phosphorus content in passenger vehicle motor oils currently has to be limited to ∼0.1 wt.%, resulting in lubricants containing ∼1.2% ZDDP in a fully formulated engine oil [1]. The EPA's mandate is to reduce phosphorus and sulphur containing pollutants being released into the environment, both these elements being major components of ZDDP.…”

Section: Introductionmentioning

confidence: 99%

A variable temperature mechanical analysis of ZDDP-derived antiwear films formed on 52100 steel

Pereira

Munoz-Paniagua

Lachenwitzer

et al. 2007

Wear

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“…Zn L-edge XANES studies have been done on ZDDP films formed thermally and mechanically. Different Zn contents and structures were found on the films at various conditions [25,26]. Morphology of ZDDP thermal films formed on gold substrates were also investigated [6].…”

Section: Introductionmentioning

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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Zinc content of ZDDP films formed thermally and mechanically

Cited by 7 publications

References 12 publications

A multi-technique characterization of ZDDP antiwear films formed on Al (Si) alloy (A383) under various conditions

A multi-technique characterization of ZDDP antiwear films formed on Al (Si) alloy (A383) under various conditions

A variable temperature mechanical analysis of ZDDP-derived antiwear films formed on 52100 steel

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

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