The Effect of a Friction Modifier Additive on Micropitting

Lainé, Emmanuel; Olver, A.D.; Lekstrom, M.; Shollock, Barbara A.; Beveridge, T. A.; Hua, D. Y.

doi:10.1080/10402000902745507

Cited by 65 publications

(53 citation statements)

References 14 publications

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“…On the other hand, another investigation by Laine et al [48] showed that the presence of friction modifier additive (MoDTC) in a formulation consisting of a mineral base stock and ZDDP significantly decreased micropit formation compared to the lubricant consisting of ZDDP alone. The positive effect of friction modifier additive (MoDTC) on reducing hydrogen permeation into the steel is also seen in our experiments as shown in Fig.…”

Section: The Effect Of Lubricant Additives On Hydrogen Permeationmentioning

confidence: 99%

Development of a novel in-situ technique for hydrogen uptake evaluation from a lubricated tribocontact

Esfahani

Morina

Han³

et al. 2017

Tribology International

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Development of a novel in-situ technique for hydrogen uptake evaluation from a lubricated tribocontact, Tribiology International, http://dx.doi.org/10. 1016/j.triboint.2017.01.019 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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Section: The Effect Of Lubricant Additives On Hydrogen Permeationmentioning

confidence: 99%

Development of a novel in-situ technique for hydrogen uptake evaluation from a lubricated tribocontact

Esfahani

Morina

Han³

et al. 2017

Tribology International

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“…Before the model is applied to gear micropitting, its suitability for prediction of micropitting in gear applications is first confirmed by comparing its predictions to experimental measurements of micropitting obtained under conditions typical of gear teeth contacts. For this purpose, micropitting damage was generated under controlled conditions on a triple disc machine (PCS Instruments MPR rig), extensively used for micropitting studies in the past [6][7][8][9]23]. The rig is shown in Fig.…”

Section: Experimental Set-up and Proceduresmentioning

confidence: 99%

“…Largely owing to the work of Olver and co-workers [5][6][7][8], micropitting is today recognized to be a surface contact fatigue phenomenon that involves a competition between asperity level fatigue and mild wear. Asperity interaction in poorly lubricated rolling-sliding, heavilyloaded contacts produces surface fatigue, while mild wear reduces the asperity heights and removes the top fatigued layers of material, which in turn acts to prevent or, at least reduce, the progression of surface fatigue.…”

Section: Introductionmentioning

confidence: 99%

“…Metalographical and morphological aspects of micropitting are described in [20][21][22]. Olver and co-workers [5][6][7][8] focus on the influence of lubricant additives and lambda ratio on the progression of micropitting using a triple-disc contact fatigue rig, while Rycerz and Kadiric [23] utilise the same rig to study the influence of slide-roll-ratio on micropitting.…”

Section: Introductionmentioning

confidence: 99%

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Prediction of micropitting damage in gear teeth contacts considering the concurrent effects of surface fatigue and mild wear

Morales-Espejel

Rycerz

Kadiric

2018

Wear

135

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A B S T R A C TThe present paper studies the occurrence of micropitting damage in gear teeth contacts. An existing general micropitting model, which accounts for mixed lubrication conditions, stress history, and fatigue damage accumulation, is adapted here to deal with transient contact conditions that exist during meshing of gear teeth. The model considers the concurrent effects of surface fatigue and mild wear on the evolution of tooth surface roughness and therefore captures the complexities of damage accumulation on tooth flanks in a more realistic manner than hitherto possible. Applicability of the model to gear contact conditions is first confirmed by comparing its predictions to relevant experiments carried out on a triple-disc contact fatigue rig. Application of the model to a pair of meshing spur gears shows that under low specific oil film thickness conditions, the continuous competition between surface fatigue and mild wear determines the overall level as well as the distribution of micropitting damage along the tooth flanks. The outcome of this competition in terms of the final damage level is dependent on contact sliding speed, pressure and specific film thickness. In general, with no surface wear, micropitting damage increases with decreasing film thickness as may be expected, but when some wear is present micropitting damage may reduce as film thickness is lowered to the point where wear takes over and removes the asperity peaks and hence reduces asperity interactions. Similarly, when wear is negligible, increased sliding can increase the level of micropitting by increasing the number of asperity stress cycles, but when wear is present, an increase in sliding may lead to a reduction in micropitting due to faster removal of asperity peaks. The results suggest that an ideal situation in terms of surface damage prevention is that in which some mild wear at the start of gear pair operation adequately wears-in the tooth surfaces, thus reducing subsequent micropitting, followed by zero or negligible wear for the rest of the gear pair life. The complexities of the interaction between the contact conditions, wear and surface fatigue, as evident in the present results, mean that a full treatment of gear micropitting requires a numerical model along the lines of that applied here, and that use of overly simplified criteria may lead to misleading predictions.

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“…The MPR is adjustable and can be run under various conditions suitable for screening fluids for micro-and macro-pitting performance [8,9]. The conditions implemented in this study are outlined in Table 2.…”

Section: Mpr Pitting Test Protocolmentioning

confidence: 99%

The Effect of Poly(alkyl methacrylate) Film-Formers on Pitting Performance of Driveline Fluids

Krapfl

Shakhvorostov

Langston³

et al. 2012

Tribology Online

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Driven by diminishing fossil fuel resources, global warming and subsequently rigid legislation on CO 2 emission, fuel economy is a major challenge for the automotive industry. Each element of the powertrain has been optimized or newly designed to increase efficiency. In this optimization process the engine oils and transmission fluids are important design elements and their contribution to improved efficiency is significant. Polyalkylmethacrylates (PAMAs) are widely used as viscosity index improvers in engine, transmission and hydraulic oils. They have been shown to adsorb from oil solution onto metal surfaces to produce thick and viscous boundary films. These films are maintained even in low speed and high temperature conditions and thus produce a reduction of friction and wear. It was found that specifically designed film-forming PAMAs can improve pitting performance of lubricant formulations. The paper describes the impact of tailor-made functionalized PAMAs on boundary film formation and explores their ability to increase the fatigue life of lubricants.

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The Effect of a Friction Modifier Additive on Micropitting

Cited by 65 publications

References 14 publications

Development of a novel in-situ technique for hydrogen uptake evaluation from a lubricated tribocontact

Development of a novel in-situ technique for hydrogen uptake evaluation from a lubricated tribocontact

Prediction of micropitting damage in gear teeth contacts considering the concurrent effects of surface fatigue and mild wear

The Effect of Poly(alkyl methacrylate) Film-Formers on Pitting Performance of Driveline Fluids

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