Asperity level tribological investigation of automotive bore material and coatings

Umer, Jamal; Morris, Nicholas J.; Leighton, Michael; Rahmani, Ramin; Howell-Smith, S.J.; Wild, R. K.; Rahnejat, Homer

doi:10.1016/j.triboint.2017.08.023

Cited by 27 publications

(33 citation statements)

References 53 publications

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“…One is the pressure coefficient of boundary shear strength, and the other is the reduced (effective) elastic modulus of the contacting surfaces, * ; taking into account the effect of any tribo-film present. This makes a significant difference to the accuracy of predicted boundary friction [30] as it affects the calculated asperity load carrying capacity through equation (9).…”

Section: Nano-scale Experimental Approachmentioning

confidence: 99%

“…The AFM was then operated as a nano-indenter by loading the tip-surface contact and measuring the distance when the probe is lowered towards the surface, as well as the deflection of its cantilever support. More information on this procedure is reported by Umer et al [30]. The indentation measurements were conducted using RTESP-525 3 4 tips with a cantilever stiffness of 200 / and a nominal tip radius of 8 nm (measured to be 11.1 nm).…”

Section: Nano-scale Experimental Approachmentioning

confidence: 99%

“…This outcome is in line with the findings of Enachescu et al [25] who used a similar analysis for DLC coated surfaces. The DMT model has been used to predict the tip-sample contact area as [30]:…”

Section: Nano-scale Analytical Contact Mechanics Modelmentioning

confidence: 99%

“…Lantz et al [26] used the MD theory [29] because of the sharp profile of the tip and the existence of intermediate levels of elastic deformation. Umer et al [30] used lateral force microscopy and nano-scale elasticity measured by AFM for six-cylinder liner bore materials and coatings including Cast Iron, Nickel-Silicon carbide, Diamond Like Carbon (DLC), Plasma Electrolytic Oxide, Iron Molybdenum and Titanium Dioxide. An AFM probe with radius of 20 and spring constant of 0.06 / was used for LFM, and for nano-scale modulus of elasticity an AFM probe of spring constant 200 / with tip radius of 8 was used.…”

Section: Introductionmentioning

confidence: 99%

“…An AFM probe with radius of 20 and spring constant of 0.06 / was used for LFM, and for nano-scale modulus of elasticity an AFM probe of spring constant 200 / with tip radius of 8 was used. Umer et al [30] showed that friction is dependent on elastic modulus, surface energy and interfacial shear strength. Carpick et al [24], Enaschescu et al [25], Lantz et al [26] and Umer et al [30] all describe friction measured through LFM as dependent on the real contact area.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Nano and microscale contact characteristics of tribofilms derived from fully formulated engine oil

Umer

Morris

Leighton

et al. 2019

Tribology International

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A systematic approach is required in order to determine the frictional characteristics of a contacting pair in the presence of a tribofilm. Despite the clear benefits in functionality and in reducing wear, the generation of ZDDP-based tribofilms often lead to increased frictional losses. Such an increase is also observed in the tribometric tests reported here, as well as in open literature. This paper investigates the underlying mechanics for the rise in friction using an integrated methodology, based upon Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS). The use of an analytical contact mechanics model demonstrates that the pressure coefficient of boundary shear strength, measured using lateral force microscopy, provides an explanation for the observed increase in measured friction at micro-scale.

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Section: Nano-scale Experimental Approachmentioning

confidence: 99%

Section: Nano-scale Experimental Approachmentioning

confidence: 99%

Section: Nano-scale Analytical Contact Mechanics Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Nano and microscale contact characteristics of tribofilms derived from fully formulated engine oil

Umer

Morris

Leighton

et al. 2019

Tribology International

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Multiscale Friction in Lubricant-Surface Systems for High-Performance Transmissions Under Mild Wear

et al. 2018

Self Cite

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The lubricant-surface system is complex in nature and can significantly affect the frictional performance of high-performance transmission systems. The complexity stems from the coupled mechanical and chemical phenomena that occur at the interfacial tooth conjunctions. A combined analytical and precision experimental approach is presented to analyse the salient parameters of the lubricant-surface system. A multiscale procedure comprising topographical measurement, pin-on-disc tribometry, atomic force microscopy in lateral force mode, X-ray photo-electron spectroscopy and continuum contact mechanics analysis under mixed non-Newtonian thermo-elastohydrodynamics is used to describe the formation of a tribo-film, as well as wear and frictional characteristics of the lubricant-surface system. The contribution of chemisorbed and physisorbed bonded tribo-film on the boundary coefficient of friction is ascertained at different physical scales. Therefore, the paper presents a novel multiscale analysis, promoting improved understanding of the complex interactions between mechanisms of friction, wear and surface chemistry.

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Dry Sliding Wear Behaviour of Nano Coating: Influence of Coating Parameters and Surface Roughness

Raghavendra¹,

Basavarajappa

Sogalad

2021

Trans Indian Inst Met

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Asperity level tribological investigation of automotive bore material and coatings

Cited by 27 publications

References 53 publications

Nano and microscale contact characteristics of tribofilms derived from fully formulated engine oil

Nano and microscale contact characteristics of tribofilms derived from fully formulated engine oil

Multiscale Friction in Lubricant-Surface Systems for High-Performance Transmissions Under Mild Wear

Dry Sliding Wear Behaviour of Nano Coating: Influence of Coating Parameters and Surface Roughness

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