The role of MoDTC tribochemistry in engine tribology performance. A Raman microscopy investigation

Espejo, Cayetano; Wang, Chun; Thiébaut, Benoît; Charrin, C.; Neville, Anne; Morina, Ardian

doi:10.1016/j.triboint.2020.106366

Cited by 25 publications

(15 citation statements)

References 42 publications

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“…It is well recognized that tribolayers formed by the chemical reaction at sliding interfaces, that is, tribochemical reactions, can reduce the friction coefficient of tribological systems. Thus, knowledge of these tribochemical reactions is important for reducing the energy loss and carbon dioxide emissions of mechanical systems. − …”

Section: Introductionmentioning

confidence: 99%

Three Tribolayers Self-Generated from SiC Individually Work for Reducing Friction in Different Contact Pressures

Ootani

Nakamura

et al. 2022

J. Phys. Chem. C

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The low friction of silicon carbide (SiC)/water systems is understood to be the result of a self-forming silica-based tribolayer that is produced by tribochemical reactions. Although several experimental studies have revealed that this silica-based tribolayer contains a considerable amount of carbon, the detailed structure of the tribolayer and its role in providing low friction remain unclear. Here, we conducted a reactive molecular dynamics sliding simulation of an amorphous SiC (a-SiC)/water system to elucidate the atomic-scale structure of the self-forming tribolayer and the mechanism underlying its formation. We found that the water selectively oxidized Si atoms at the surface of the a-SiC, resulting in their removal as SiO 2 wear particles. Some of these wear particles dissolved in the water, resulting in the formation of colloidal silica, whereas others were deposited on the a-SiC surface, where they formed a layer of silica hydrate. Meanwhile, carbon atoms remained at the a-SiC surface and formed a C-rich layer, which corresponds to the initial process of an amorphous carbon layer formation. Based on our findings, we propose that colloidal silica, silica hydrate, and amorphous carbon act as individual tribolayers to reduce friction in the low-, intermediate-, and high-contactpressure areas, respectively. In the low-contact-pressure area, water mainly separates the surfaces, and the silica hydrate holds the water at the sliding interface because of its high hydrophilicity, increasing the load-carrying capacity of the water. In the intermediate-contact-pressure area, the water cannot separate the surfaces, but the colloidal silica layer can because of its high viscosity. In the high-contact-pressure area, where the water and silica-based layers are broken, the amorphous carbon layer works as a solid lubricant. Thus, the three self-forming tribolayers together produce the low friction that characterizes SiC/water systems.

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Section: Introductionmentioning

confidence: 99%

Three Tribolayers Self-Generated from SiC Individually Work for Reducing Friction in Different Contact Pressures

Ootani

Nakamura

et al. 2022

J. Phys. Chem. C

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“…The friction reduction mechanism is based on MoDTC molecule chemical bonds rupture and 2D MoS2 nanosheets formation during boundary lubrication conditions. The reduction of friction is obtained in tribometer testing conditions [9]- [11] and engine tests [12],…”

Section: Introductionmentioning

confidence: 99%

“…MoS2 distinct peaks appear in Raman spectra at 383 cm -1 and 408 cm -1 Raman shift, corresponding to A1g and E 1 2g vibrational modes [9]- [11]. Raman Microscopy based characterisation of engine components, conducted by Espejo et al [12], showed that even a small amount of MoDTC in the fully formulated lubricant could lead to MoS2 formation in the engine and significantly impact the friction performance. In their work, MoS2 formation was detected at the Bottom Dead Centre (BDC) area and near the Top Dead Centre (TDC) area on the liner.…”

Section: Introductionmentioning

confidence: 99%

Low friction tribofilm formation and distribution on an engine cylinder tested with MoDTC-containing low viscosity engine lubricants

Vaitkūnaitė

Espejo

Thiébaut

et al. 2022

Tribology International

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“…Recent studies have shown that ultrafine particles made of metal elements, polymers, organic, and inorganic materials can effectively reduce wear (Shahnazar et al , 2021; Singh et al , 2021). However, commonly lubricating oil additives, such as dithiocarbamate molybdenum (Espejo et al , 2020) and zinc dialkyl dithiophosphate (ZDDP) (Naveira et al , 2011), contain a large amount of sulphur, phosphorus and chlorine, which have an adverse effect on the environment. Thus, the green additive that reduces energy consumption and improves energy efficiency has become a hot topic in this field (Awang et al , 2019).…”

Section: Introductionmentioning

confidence: 99%

Tribological effect of ZBUP additive on the running-in quality of sliding bearing by fractal analysis

Wang

Zhou

Zuo

2022

ILT

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Purpose The purpose of this paper is to study the tribological effect of zinc borate ultrafine powder (ZBUP) oil additive on the running-in quality. Design/methodology/approach The running-in quality was assessed by friction coefficient and surface topography. Fractal parameters including fractal dimension, the width of multifractal, the multifractal difference, multifractal parameters, phase trajectory and correlation dimension were used to extract the nonlinear characteristics of surface topography and friction coefficient. Findings When the ZBUP additive was added, the convergence degree of the phase trajectory and the stability of the running in were higher than that of base oil. It indicates that the ZBUP additive can improve the running-in quality of sliding bearing. Besides, the ZBUP additive can shorten the running-in time. A boundary protective film, which has good friction-reducing and anti-wear effects, was generated on the surface when the ZBUP additive was added. Originality/value The results have a great significance to improve the running-in quality and prolong the service life of the sliding bearing.

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The role of MoDTC tribochemistry in engine tribology performance. A Raman microscopy investigation

Abstract: This is a repository copy of The role of MoDTC tribochemistry in engine tribology performance. A Raman microscopy investigation.

Cited by 25 publications

References 42 publications

Three Tribolayers Self-Generated from SiC Individually Work for Reducing Friction in Different Contact Pressures

Three Tribolayers Self-Generated from SiC Individually Work for Reducing Friction in Different Contact Pressures

Low friction tribofilm formation and distribution on an engine cylinder tested with MoDTC-containing low viscosity engine lubricants

Tribological effect of ZBUP additive on the running-in quality of sliding bearing by fractal analysis

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