Boundary lubrication: adsorption of oil additives on steel and ceramic surfaces and its influence on friction and wear

Studt, P.

doi:10.1016/0301-679x(89)90171-0

Cited by 97 publications

(43 citation statements)

References 7 publications

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“…There is, however, still some disagreement about whether or not friction levels out above a critical chain length [8][9][10]. Branched chain acids were generally found less ineffective than straight chain ones [11]. It was shown that to reduce friction, enough carboxylic acid must be present to form a complete vertically oriented monolayer [8].…”

Section: In the Extreme Case We May Picture Each Of The Metallic Surfmentioning

confidence: 99%

In Situ Study of Model Organic Friction Modifiers Using Liquid Cell AFM; Saturated and Mono-unsaturated Carboxylic Acids

et al. 2015

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Fatty acids and their derivatives have been used as model organic friction modifiers for almost a century, but there is still debate as to the nature of the boundary films that they form on rubbed surfaces. In this study, in situ liquid cell atomic force microscopy (AFM) is used to monitor the self-assembly of boundary films from solutions of fatty acids in alkanes on to mica surfaces. Because the mica surfaces are wholly immersed in solution it is possible to study directly changes in the morphology and friction of these films over time and during heating and cooling.It has been found that stearic and elaidic acid, that are able to adopt a linear molecular configurations, form irregular islands on mica that are tens to hundreds of microns in diameter and typically 1.6 nm thick, corresponding to domains of tilted single monolayers. At a relatively high concentration of 0.01M, stearic acid in hexadecane forms an almost complete monolayer, but at lower concentrations, in dodecane solution and for elaidic acid solutions these films remain incomplete after prolonged immersion of more than a day. The films formed by fatty acids on mica are displaced by repeated scanning in contact mode AFM but can be imaged without damage using tapping mode AFM.Rubbed quartz surfaces from a sliding ball-on-disc test were also scanned ex-situ using AFM and these showed that stearic acid forms similar monolayer island films on quartz in macroscale friction experiments as are found on mica.Oleic acid solutions behave quite differently from stearic acid and elaidic acid, forming irregular globular films on both mica and rubbed quartz surfaces. This is believed to be because its cis-double bond geometry means that, unlike its trans-isomer elaidic acid or saturated stearic acid, it is unable to adopt a linear molecular configuration and so is less able to form close-packed monolayers.

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Section: In the Extreme Case We May Picture Each Of The Metallic Surfmentioning

confidence: 99%

In Situ Study of Model Organic Friction Modifiers Using Liquid Cell AFM; Saturated and Mono-unsaturated Carboxylic Acids

et al. 2015

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“…Thermal and thermo-mechanical models have been presented for the additive bonding process. [27][28][29] Although there have been significant advances in probabilistic macro-scale models of the mixed regime of lubrication, [30][31][32] these have remained dependent on key input parameters for the prediction of boundary friction. Therefore, predictions using such models can be enhanced with the inclusion of data obtained from experimental measurements.…”

Section: Introductionmentioning

confidence: 99%

Combined lubricant–surface system perspective: Multi-scale numerical–experimental investigation

Leighton

Nicholls

Cruz

et al. 2016

Proceedings of the Institution of Mechanical Engineers, Part J:

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Frictional losses are one of the main causes of reduced energy efficiency in all machines and mechanisms. In particular, there is mounting pressure upon manufacturers of all forms of vehicle to comply with increasingly stringent legislation and directives with regard to harmful emissions. Therefore, reduction of friction has become an imperative issue. The traditional approach of dealing with surface material and lubricant formulation in isolation has been replaced by a lubricant-surface system approach. This paper presents multi-scale experimentation from nano/meso-scale lateral force microscopy of ultra-thin surface adsorbed films through to micro-scale precision sliding tribometry to investigate lubricant-surface friction optimisation within the mixed regime of lubrication, using lubricants with different organic and inorganic friction modifying species. These affect the parameters of the system, commonly used as input to models for mixed and boundary regimes of lubrication. Therefore, the precise measurement of these parameters at different physical scales is important. The study also makes use of detailed numerical predictions at micro-scale through combined solution of the average Reynolds equation as well as interaction of wetted asperities in mixed and boundary regimes of lubrication. Good agreement is found between the predictions and measurements at micro-scale tribometric interactions. Furthermore, the same trends are observed in testing across the physical scales.

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“…Many studies using different base oil lubricants [13], paraffin oils [14] and additives [11,15] have been done and published recently. However, none of them have used POME as base lubricant or additive.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the anti-wear characteristics of palm oil methyl ester using a four-ball tribometer test

Masjuki

Maleque

1997

Wear

103

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Boundary lubrication: adsorption of oil additives on steel and ceramic surfaces and its influence on friction and wear

Cited by 97 publications

References 7 publications

In Situ Study of Model Organic Friction Modifiers Using Liquid Cell AFM; Saturated and Mono-unsaturated Carboxylic Acids

In Situ Study of Model Organic Friction Modifiers Using Liquid Cell AFM; Saturated and Mono-unsaturated Carboxylic Acids

Combined lubricant–surface system perspective: Multi-scale numerical–experimental investigation

Investigation of the anti-wear characteristics of palm oil methyl ester using a four-ball tribometer test

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