Influence of PMA on the anti-scuffing properties of AW/EP additives

Ueda, Mao; Kadiric, Amir; Spikes, H. A.

doi:10.1016/j.triboint.2022.107756

Cited by 4 publications

(2 citation statements)

References 27 publications

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“…The chemical structural formula of common nondispersant PMA-based polymer additives is shown in Figure a. PMA-based additives are one of the most common oil-compatible polymer additives, and there have been several reports on their improvement of tribological properties. − [Note that the olefin copolymer (OCP)-based additives shown in Figure b were used for comparison in the mechanical response study described in the latter part of this paper. ]…”

Section: Experiments and Resultsmentioning

confidence: 99%

Adsorption Characteristics and Mechanical Responses of Lubricants Containing Polymer Additives under Fluid Lubrication with a Narrow Gap

Hirayama,

Yamashita,

Yamamoto

et al. 2024

Langmuir

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The adsorption behavior of poly(methyl acrylate) (PMA)-based polymer additives and their mechanical response under fluid lubrication in narrow gaps were investigated by using neutron reflectometry, microchannel devices, and the narrow gap viscometer. The surface adsorption layer formed by the polymer additive in a stationary field that was investigated by neutron reflectometry was only about 3 nm thick. On the other hand, when the sample oil containing the polymer additive was flowed into the microchannel device with channels about 500 nm deep, the adsorption layer grew over a long period of time and eventually formed a layer that appeared to be more than 100 nm thick. The mechanical response was measured during one-directional rotation with a constant gap length by using the narrow gap viscometer. The results showed that the effective viscosity increased in the low shear rate range. The same behavior was also observed in the reciprocating rotational tests, where the mechanical response showed a distinctive distortion only when the shear rate was low near 0 rpm. The results of the neutron reflectometer, incorporating the narrow gap viscometer, showed no effect of the rotational speed with regard to the structure of the homogeneous layer over a large area. However, the discrepancy between the reflectivity profile and the fitting curve became progressively more pronounced with time, confirming the formation of inhomogeneous structures with time. It is finally suggested that the inhomogeneous structure is due to the formation of local aggregates by PMA molecules, and it acts as flow resistance only in the low shear rate, resulting in an increase in effective viscosity.

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Section: Experiments and Resultsmentioning

confidence: 99%

Adsorption Characteristics and Mechanical Responses of Lubricants Containing Polymer Additives under Fluid Lubrication with a Narrow Gap

Hirayama,

Yamashita,

Yamamoto

et al. 2024

Langmuir

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“…The substrate materials will be exposed and massive surface wear as well as severe lubrication failure, like scuffing, may occur [12,27]. Therefore, scuffing failure under boundary lubrication is controlled by the nature and effectiveness of the tribofilms formed on the surface [28,29]. The time for the final breakdown of the protective tribofilm is inversely dependent on the applied load and it was shown that higher contact loads resulted in premature breakdown of the tribofilm [27].…”

Section: Introductionmentioning

confidence: 99%

Scuffing failure analysis based on a multidisciplinary coupling model and experimental verification

Lyu

Meng

Yin

et al. 2023

Preprint

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General reductions in lubricant viscosities and increased loads in many machine components mean that the role of tribofilms has become increasingly important to provide adequate surface protection against scuffing. However, the relationship between the scuffing process and the growth and removal of tribofilm has not been systematically demonstrated. In this study, a multidisciplinary coupling model, which includes hydrodynamic lubrication, asperity contact, thermal effect, tribochemistry reaction, friction, and surface wear, was developed to capture the initiation of surface scuffing. Simulations and experiments for a piston ring and cylinder liner contact were conducted following a step-load sequence under different temperature conditions. The results show that high temperature and extreme load could induce the lubricant film collapse, and then the tribofilm breakdown initiates due to the substantially increased removal process. The failures of both lubricant film and tribofilm progress instantaneously in a coupling way, which finally leads to severe scuffing.

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Scuffing failure analysis based on a multiphysics coupling model and experimental verification

Lyu,

Meng,

Yin

et al. 2023

Friction

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General reductions in lubricant viscosities and increasing loads in machine components highlight the role of tribofilms in providing surface protection against scuffing. However, the relationship between the scuffing process and the growth and removal of tribofilm is not well understood. In this study, a multiphysics coupling model, which includes hydrodynamic lubrication, asperity contact, thermal effect, tribochemistry reaction, friction, and surface wear, was developed to capture the initiation of surface scuffing. Simulations and experiments for a piston ring and cylinder liner contact were conducted following a step-load sequence under different temperature conditions. The results show that high temperature and extreme load could induce the lubricant film collapse, which in turn triggers the breakdown of the tribofilm due to the significantly increased removal process. The failures of both lubricant film and tribofilm progress instantaneously in a coupling way, which finally leads to severe scuffing.

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Influence of PMA on the anti-scuffing properties of AW/EP additives

Cited by 4 publications

References 27 publications

Adsorption Characteristics and Mechanical Responses of Lubricants Containing Polymer Additives under Fluid Lubrication with a Narrow Gap

Adsorption Characteristics and Mechanical Responses of Lubricants Containing Polymer Additives under Fluid Lubrication with a Narrow Gap

Scuffing failure analysis based on a multidisciplinary coupling model and experimental verification

Scuffing failure analysis based on a multiphysics coupling model and experimental verification

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