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Benoît Thiebaut - One of the best experts on this subject based on the ideXlab platform.

  • Effect of ZDDP on Lubrication mechanisms of linear fatty amines under Boundary Lubrication conditions
    Tribology International, 2020
    Co-Authors: Toni Massoud, Benoît Thiebaut, Thierry Le Mogne, Michel Belin, Rafael Pereira De Matos, Manuel Cobian, Sophie Loehlé, Franck Dahlem, Clotilde Minfray
    Abstract:

    Abstract The tribological behavior of different linear amines blended to PAO4 alone or in combination with ZDDP was investigated under Boundary Lubrication Regime via the coupling of tribometry and XPS measurements. Using a reciprocating ball-on-flat tribometer, it was evidenced that all tested amines were able to reduce both friction and wear. The combination of primary monoamine (1 wt %) and ZDDP (1 wt %) produced synergistic effect on reduction of both friction and wear in most cases. Experimental investigations suggest that this synergistic effect is due to the fast formation of a zinc-oxide-enriched tribofilm depleted in phosphates. Moreover, our results show that the Lubrication mechanism and the composition of the tribofilm are strongly dependent on the amine/ZDDP molar ratio.

  • WS2 nanoparticles anti-wear and friction reducing properties on rough surfaces in the presence of ZDDP additive
    Tribology International, 2016
    Co-Authors: Paula Ussa Aldana, Thierry Le Mogne, Fabrice Dassenoy, Béatrice Vacher, Benoît Thiebaut
    Abstract:

    Abstract The effect of WS 2 nanoparticles used as lubricant additives in PAO alone and in presence of ZDDP additive on the Lubrication of rough surfaces has been studied at 100 °C in the Boundary Lubrication Regime. The results showed that the use of nanoparticles in PAO base oil reduces both wear and friction by around 70% compared to PAO. The surface analyzes revealed that a tribofilm is formed on the steel surface and that nanoparticles can be trapped in the steel grooves. These trapped nanoparticles could provide proper Lubrication of the contact zone in case of nanoparticle starvation. The presence of ZDDP additive in the lubricant enhances the friction reducing and anti-wear effect of the nanoparticles.

  • Action mechanism of WS2 nanoparticles with ZDDP additive in Boundary Lubrication Regime
    Tribology Letters, 2014
    Co-Authors: Paula Ussa Aldana, Benoît Thiebaut, Blandine Vacher, Thierry Le Mogne, Michel Belin, Fabrice Dassenoy
    Abstract:

    The effect in the tribological performance of WS2 fullerene-like nanoparticles in PAO base oil when adding a ZDDP additive was studied at 100C in the Boundary Lubrication Regime. The tribological properties of the dispersion surpass those obtained without one of the two additives. The friction modifier properties of the par- ticles are improved in the presence of ZDDP, while the anti-wear properties of the ZDDP are increased when the particles are added to the dispersion. The composition of the formed tribofilm was investigated. Results show that a 50–60 nm tribofilm is formed on the steel surface com- posed by WS2 mixed on the ZDDP chemical tribofilm. AWS2-rich layer is observed at the top of the tribofilm. A correlation between the chemical composition of the tribofilm and the tribological properties of the ‘‘PAO + WS2 + ZDDP’’ dispersion was made. Synergy between the two additives was proven.

Mitjan Kalin - One of the best experts on this subject based on the ideXlab platform.

  • influence of concentration and anion alkyl chain length on tribological properties of imidazolium sulfate ionic liquids as additives to glycerol in steel steel contact Lubrication
    Tribology International, 2016
    Co-Authors: Vladimir Pejakovic, C Tomastik, Nora Dorr, Mitjan Kalin
    Abstract:

    Commercially available ionic liquids were used as additives in the model lubricant fluid glycerol. The stability of the mixtures was controlled by measuring of turbidity. Tribological experiments have been performed on a reciprocating sliding tribometer in the Boundary Lubrication Regime with three ionic liquid concentrations, as well as with neat glycerol and the neat ionic liquids at 100 °C. Wear and friction were measured, and the worn surfaces were examined with optical microscopy, atomic force microscopy and X-ray photoelectron spectroscopy. The results show the influence of the ionic liquid concentration and the anion alkyl chain length on the tribological behavior. Significant improvement in friction and wear reduction at low ionic liquid concentrations was detected and attributed to sulfur species in tribofilm.

  • Methodology of a statistical and DOE approach to the prediction of performance in tribology – A DLC Boundary-Lubrication case study
    Tribology International, 2016
    Co-Authors: Kosta Simonovic, Mitjan Kalin
    Abstract:

    Abstract This paper presents a well-defined methodology for empirical modeling in tribology that was verified using the results from several tribometers. We propose a sequence of required statistical methods used to develop an empirical model and we discuss in detail why they are appropriate for use in tribology, in comparison with other possible solutions. A step-by-step guide for the generation of an empirical friction model, as a case study, is illustrated for steel–steel and steel–DLC contacts in the Boundary Lubrication Regime lubricated with a commercial, fully formulated oil (5W30, EACEA A5/B5).

  • Mechanisms and improvements in the friction and wear behavior using MoS2 nanotubes as potential oil additives
    Wear, 2012
    Co-Authors: Mitjan Kalin, J. Kogovšek, Maja Remškar
    Abstract:

    Abstract Several types of nanoparticles have been experimentally investigated as possible Lubrication agents and the results suggest that this is a promising idea. However, so far, MoS 2 nanotubes have not been experimentally evaluated in this respect. Accordingly, this study is focused on the tribological behavior of MoS 2 multi-wall nanotubes (MWNTs) as a potential additive in lubricating oils. The experiments were performed in the Boundary-Lubrication Regime under a contact pressure of 1 GPa (Hertz, max) and a sliding velocity of 0.005 m/s using a ball-on-disc tribotester. The results were compared to a reference base oil, and it was found that MoS 2 nanotubes significantly decreased the friction and wear compared to the base lubricant. The friction was more than 2-times lower and the wear as much as 5–9-times lower. Several tribological mechanisms and effects due to the MoS 2 nanotubes are presented. It was established that a wear-protective and low-shear film was forming on the surface. This tribofilm was formed either by (i) the adhesion of thin MoS 2 nano-sheets on the surface, where these sheets were deposited on the surface by one of the four possible sub-mechanisms proposed in this work; or by (ii) the compaction and deformation of nanotube aggregates, which resulted in a thicker Boundary film. Thus, in contrast to the rolling of the nanotubes, which we do not consider to be plausible, the exfoliation and deformation of the nanotubes were found to be the prevalent effects for the nanotubes in the Boundary-Lubrication Regime.

Thierry Le Mogne - One of the best experts on this subject based on the ideXlab platform.

  • Effect of ZDDP on Lubrication mechanisms of linear fatty amines under Boundary Lubrication conditions
    Tribology International, 2020
    Co-Authors: Toni Massoud, Benoît Thiebaut, Thierry Le Mogne, Michel Belin, Rafael Pereira De Matos, Manuel Cobian, Sophie Loehlé, Franck Dahlem, Clotilde Minfray
    Abstract:

    Abstract The tribological behavior of different linear amines blended to PAO4 alone or in combination with ZDDP was investigated under Boundary Lubrication Regime via the coupling of tribometry and XPS measurements. Using a reciprocating ball-on-flat tribometer, it was evidenced that all tested amines were able to reduce both friction and wear. The combination of primary monoamine (1 wt %) and ZDDP (1 wt %) produced synergistic effect on reduction of both friction and wear in most cases. Experimental investigations suggest that this synergistic effect is due to the fast formation of a zinc-oxide-enriched tribofilm depleted in phosphates. Moreover, our results show that the Lubrication mechanism and the composition of the tribofilm are strongly dependent on the amine/ZDDP molar ratio.

  • WS2 nanoparticles anti-wear and friction reducing properties on rough surfaces in the presence of ZDDP additive
    Tribology International, 2016
    Co-Authors: Paula Ussa Aldana, Thierry Le Mogne, Fabrice Dassenoy, Béatrice Vacher, Benoît Thiebaut
    Abstract:

    Abstract The effect of WS 2 nanoparticles used as lubricant additives in PAO alone and in presence of ZDDP additive on the Lubrication of rough surfaces has been studied at 100 °C in the Boundary Lubrication Regime. The results showed that the use of nanoparticles in PAO base oil reduces both wear and friction by around 70% compared to PAO. The surface analyzes revealed that a tribofilm is formed on the steel surface and that nanoparticles can be trapped in the steel grooves. These trapped nanoparticles could provide proper Lubrication of the contact zone in case of nanoparticle starvation. The presence of ZDDP additive in the lubricant enhances the friction reducing and anti-wear effect of the nanoparticles.

  • Action mechanism of WS2 nanoparticles with ZDDP additive in Boundary Lubrication Regime
    Tribology Letters, 2014
    Co-Authors: Paula Ussa Aldana, Benoît Thiebaut, Blandine Vacher, Thierry Le Mogne, Michel Belin, Fabrice Dassenoy
    Abstract:

    The effect in the tribological performance of WS2 fullerene-like nanoparticles in PAO base oil when adding a ZDDP additive was studied at 100C in the Boundary Lubrication Regime. The tribological properties of the dispersion surpass those obtained without one of the two additives. The friction modifier properties of the par- ticles are improved in the presence of ZDDP, while the anti-wear properties of the ZDDP are increased when the particles are added to the dispersion. The composition of the formed tribofilm was investigated. Results show that a 50–60 nm tribofilm is formed on the steel surface com- posed by WS2 mixed on the ZDDP chemical tribofilm. AWS2-rich layer is observed at the top of the tribofilm. A correlation between the chemical composition of the tribofilm and the tribological properties of the ‘‘PAO + WS2 + ZDDP’’ dispersion was made. Synergy between the two additives was proven.

Paula Ussa Aldana - One of the best experts on this subject based on the ideXlab platform.

  • WS2 nanoparticles anti-wear and friction reducing properties on rough surfaces in the presence of ZDDP additive
    Tribology International, 2016
    Co-Authors: Paula Ussa Aldana, Thierry Le Mogne, Fabrice Dassenoy, Béatrice Vacher, Benoît Thiebaut
    Abstract:

    Abstract The effect of WS 2 nanoparticles used as lubricant additives in PAO alone and in presence of ZDDP additive on the Lubrication of rough surfaces has been studied at 100 °C in the Boundary Lubrication Regime. The results showed that the use of nanoparticles in PAO base oil reduces both wear and friction by around 70% compared to PAO. The surface analyzes revealed that a tribofilm is formed on the steel surface and that nanoparticles can be trapped in the steel grooves. These trapped nanoparticles could provide proper Lubrication of the contact zone in case of nanoparticle starvation. The presence of ZDDP additive in the lubricant enhances the friction reducing and anti-wear effect of the nanoparticles.

  • Action mechanism of WS2 nanoparticles with ZDDP additive in Boundary Lubrication Regime
    Tribology Letters, 2014
    Co-Authors: Paula Ussa Aldana, Benoît Thiebaut, Blandine Vacher, Thierry Le Mogne, Michel Belin, Fabrice Dassenoy
    Abstract:

    The effect in the tribological performance of WS2 fullerene-like nanoparticles in PAO base oil when adding a ZDDP additive was studied at 100C in the Boundary Lubrication Regime. The tribological properties of the dispersion surpass those obtained without one of the two additives. The friction modifier properties of the par- ticles are improved in the presence of ZDDP, while the anti-wear properties of the ZDDP are increased when the particles are added to the dispersion. The composition of the formed tribofilm was investigated. Results show that a 50–60 nm tribofilm is formed on the steel surface com- posed by WS2 mixed on the ZDDP chemical tribofilm. AWS2-rich layer is observed at the top of the tribofilm. A correlation between the chemical composition of the tribofilm and the tribological properties of the ‘‘PAO + WS2 + ZDDP’’ dispersion was made. Synergy between the two additives was proven.

Nicholas D. Spencer - One of the best experts on this subject based on the ideXlab platform.

  • In Situ Attenuated Total Reflection (ATR/FT-IR) Tribometry: A Powerful Tool for Investigating Tribochemistry at the Lubricant–Substrate Interface
    Tribology Letters, 2011
    Co-Authors: Filippo Mangolini, Antonella Rossi, Nicholas D. Spencer
    Abstract:

    To investigate the chemical changes occurring at metal/lubricant interfaces under tribological conditions in the Boundary-Lubrication Regime, an in situ system for conducting quantitative tribological measurements has been constructed by combining an attenuated total reflection Fourier-transform infrared (ATR/FT-IR) spectrometer with a reciprocating tribometer. By periodically acquiring ATR/FT-IR spectra during sliding, spectroscopic changes due to thermal and/or tribochemical reactions occurring at the metal/oil interface can be monitored and correlated with friction measurements. The usefulness of this tribological test system has been demonstrated by performing ATR tribological experiments in the presence of a poly-α-olefin base oil at high temperature (423 K) on iron-coated germanium ATR crystals.

  • Adsorption and surface chemistry in tribology
    Tribology International, 1997
    Co-Authors: Christopher Mcfadden, Cristian Soto, Nicholas D. Spencer
    Abstract:

    Adsorption on sliding surfaces and the chemical changes occurring within a few nanometers of the surface are key to the performance of lubricants and lubricant additives in the Boundary Lubrication Regime. By means of the methods of modern surface science, these phenomena are beginning to be elucidated on a molecular level. This knowledge will be essential, both for the development of higher-performance lubricants, capable of high-temperature operation, as well as for the design of environmentally benign alternatives to the lubricant systems in current use.