Tribochemistry of Overbased Calcium Detergents Studied by ToF-SIMS and Other Surface Analyses

Cizaire, L.; Martin, Jean‐Michel; Gresser, E.; Dinh, N. Truong; Héau, Christophe

doi:10.1007/s11249-004-8078-9

Cited by 36 publications

(24 citation statements)

References 10 publications

(11 reference statements)

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“…These include X-ray scattering [17], reflection infrared spectroscopy [18], XPS [10], TOF-SIMS [19,20] and XANES [16]. Most studies have identified a solid-like films of CaCO 3 in the form of calcite.…”

Section: Introductionmentioning

confidence: 99%

Film Forming and Friction Properties of Overbased Calcium Sulphonate Detergents

Topolovec-Miklozic

Forbus²,

Spikes

2007

Tribol Lett

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The film-forming and friction properties of overbased calcium sulphonate (OBCaSu) detergents in rolling-sliding, thin film, lubricated contact have been investigated. All of the commercial detergents studied form thick, solid-like, calcium carbonate films on the rubbed surfaces, of thickness 100-150 nm. The films have a padlike structure, interspersed by deep valleys in which practically no film is present. These films have the effect of increasing friction in intermediate speed conditions, an effect which is believed to occur because the pad structure of the film inhibits fluid entrainment and thus postpones the formation of an EHD film to higher entrainment speeds. Large differences were noted between the boundary friction coefficients of the various detergents tested. Two of them gave very low boundary friction coefficients, in the range 0.06-0.08, while the other two gave considerably higher friction. These differences are believed to originate from differences in the structures of the alkyl chains in the sulphonate detergent molecules. The films formed by OBCaSu detergents can be removed very effectively by treatment with EDTA solution and this shows that the films are effective in preventing wear.

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Section: Introductionmentioning

confidence: 99%

Film Forming and Friction Properties of Overbased Calcium Sulphonate Detergents

Topolovec-Miklozic

Forbus²,

Spikes

2007

Tribol Lett

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“…In our previous work on working mechanism on overbased sulfonates [13], we have found that calcium oxide deposited on rubbing surface plays an important role on reduction of friction and wear. Kinetics of the film formation, especially decomposition of micelle structure of the over-based sulfonate to disclose the inorganic moiety has been investigated by Time-of-flight secondary mass spectroscopy (TOF-SIMS) analysis [14].…”

Section: Introductionmentioning

confidence: 99%

TOF-SIMS analysis of boundary films derived from calcium sulfonates

et al. 2006

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Tribological properties of over-based and neutral calcium sulfonate were examined under boundary lubrication conditions by using a ball-on-flat type tribo-tester. It was found that over-based calcium sulfonate reduced friction and wear of steel-steel contacts, whereas the neutral calcium sulfonate did not. It was found that boundary film composed of calcium oxide plays significant role on improving the tribological properties. Surface analyses by XPS and Time-of-flight secondary mass spectroscopy (TOF-SIMS) revealed that the major component of the film on upper surfaces is calcium carbonate and that at subsurfaces are composed of calcium oxide. A depth profile of the film obtained by TOF-SIMS using an etching technique revealed that thickness of the film is up to 240 nm. A static pyrolysis of the over-based calcium sulfonate on steel surface affords a thin film composed of calcium oxide, indicating that rubbing process is essential for the formation of the boundary film.

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“…The effect of this deposited film is analogous to the films deposited by traditional phosphorous and sulfur containing antiwear additives like ZDDP. These films have been analyzed by a variety of techniques (ToF-SIMS [9], XRD [10], EELS [11], XPS [12], and XANES [13]) to determine their chemical and structural composition on a rubbed metal surface.…”

Section: Introductionmentioning

confidence: 99%

“…The tribofilms formed in the Cameron-Plint tribometer were studied using XPS which indicated that the calcium sulfonate chains were expelled during rubbing, while the CaCO 3 core crystallized on the metal surface. Additionally, it was conjectured that part of the CaCO 3 decomposed to CaO and CO 2 after deposition on the surface (although the mechanism is still unclear) [9].…”

Section: Introductionmentioning

confidence: 99%

Study of surface films of overbased sulfonates and sulfurized olefins by X-Ray Absorption Near Edge Structure (XANES) spectroscopy

Costello¹,

Kasrai

2006

Tribol Lett

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The X-Ray Absorption Near Edge Structure (XANES) spectroscopy technique has been successfully applied to complex matrices such as tribological films, coal, DLC films and, where other instrumental analytical techniques are less sensitive for molecular analysis. Four-ball tests were performed for lubricating oils containing the synergistic combination of overbased sulfonate (calcium and magnesium) and sulfurized olefin. The surface films were analyzed by XANES using C K-edge, Ca L-edge and S L-and K-edge. Using this technique we were able to differentiate the carbonate from organic carbon in C K-edge spectra, as well as, determining the difference between FeS, FeS 2, RSO 3 ) and SO 4 2) in the sulfur spectra. It was found while the sulfurized olefin reacts very strongly with the substrate to form FeS, the overbased calcium sulfonate and overbased magnesium sulfonate do not react strongly with the substrate without sulfurized olefin present. There is evidence to suggest that the overbased sulfonate promotes decomposition of the sulfurized olefin on the surface to form both CaSO 4 and FeS, which improves the EP performance of the lubricant.

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Tribochemistry of Overbased Calcium Detergents Studied by ToF-SIMS and Other Surface Analyses

Cited by 36 publications

References 10 publications

Film Forming and Friction Properties of Overbased Calcium Sulphonate Detergents

Film Forming and Friction Properties of Overbased Calcium Sulphonate Detergents

TOF-SIMS analysis of boundary films derived from calcium sulfonates

Study of surface films of overbased sulfonates and sulfurized olefins by X-Ray Absorption Near Edge Structure (XANES) spectroscopy

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