Molecular dynamics simulation and experimental study on the lubrication of graphene additive films

Zhang, Lixiu; Wu, Yuhou; Wang, Junhai; Zhang, Xinyue; Wang, Liyan; Xi, Dongyang

doi:10.1177/1350650119899213

Cited by 14 publications

(7 citation statements)

References 35 publications

(48 reference statements)

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“…To demonstrate how the silver nanoparticles improve the adsorption of the fluid layer to the Fe layer, we calculated the energy by intercepting the final frame of shear conformation at 400 ps. 24,25 The equations below are used to calculate the binding energy and interaction energies ( E b i n d and E , respectively) of the fluid layer with the Fe layer 26,27 : where E F l u i d and E Fe represent the energies of the fluid layer and Fe layer, respectively. These values were obtained through single-point energy calculations.…”

Section: Resultsmentioning

confidence: 99%

Mechanisms of friction and wear reduction by nanosilver additives to base oil: Molecular dynamics simulation and experimental study

Chen,

Hu,

Wang

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part J:

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Although nanosilver particles are commonly used as oil lubrication additives, their mechanism for improving lubrication at the atomic scale remains unclear. This article explains how the performance of a pentaerythritol oleate lubrication system can be improved using silver nanoparticles through molecular dynamics simulation. Additionally, tribological tests were conducted using a reciprocating friction and wear testing machine. The relative concentrations and simulated shear conformation revealed that silver nanoparticles underwent deformation under shear stress and fractured at the interlayer slip. This resulted in the formation of a deposited film that spread over both the top and bottom Fe layers. We characterized the interaction between pentaerythritol oleate molecular chains and Fe layers by analyzing interfacial interaction energies, mean square displacements, and self-diffusion coefficients. Our findings indicate that the presence of silver nanoparticles improves both the adsorption of pentaerythritol oleate molecular chains onto the Fe layer and their diffusion behavior. The results of tribological tests indicate that adding silver nanoparticles significantly reduces friction coefficient and frictional wear across various lubrication conditions. The addition of silver nanoparticles at different loads and temperatures resulted in varying reductions in the coefficient of friction and wear. At a load of 20 N and a temperature of 298 K, the coefficient of friction decreased by 9%, and wear decreased by 31%. When the load was reduced to 2 N while maintaining a temperature of 298 K, the coefficient of friction decreased by 8% and wear decreased significantly by 84%. Finally, at a load of 20 N but with an increased temperature to 373 K, there was a larger reduction in the coefficient of friction (23%) compared to wear (50%). The film-formation mechanism of improved lubrication by silver nanoparticles was verified through tribological tests and simulations.

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Section: Resultsmentioning

confidence: 99%

Mechanisms of friction and wear reduction by nanosilver additives to base oil: Molecular dynamics simulation and experimental study

Chen,

Hu,

Wang

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part J:

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“…Tribological Characteristics [197] A clear investigation was concluded about the effect of sliding velocity and load capacity on the formation of the nano tribo-films at the contacted surfaces [198] Frictional heating and anti-wear properties of the friction pair is controlled through the existence of nanoparticles [199] Simulations of MD clarified that Gr nano additives could form a thick layer of tribo-film that can help in reducing the coefficient of friction and friction force [200] Nanofluids have a higher transition pressure than the base fluid, with an excellent load-carrying capacity [201] Theoretical guidance was implemented for the lubrication mechanism of MOS2 nanoparticles [193] Confirmation of the ball-bearing lubrication mechanism of nanoparticles under mild velocities and loads [189] The load-carrying capacity of nanofluid is improved regarding the base oil before the rupture of the lubricant film [120] Atomistic simulations confirmed the mending mechanism of nanolubricants through which nanoparticles fill in valleys of the sliding asperities Over and above that, artificial intelligence models can also predict the different behaviours of lubricant performance, regarding their tribological and other behaviours [202][203][204]. One of these tools is the artificial neural network (ANN), which is considered a widely accepted novel modelling approach [203].…”

Section: Referencementioning

confidence: 99%

Recent Advances in Preparation and Testing Methods of Engine-Based Nanolubricants: A State-of-the-Art Review

et al. 2021

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Reducing power losses in engines is considered a key parameter of their efficiency improvement. Nanotechnology, as an interface technology, is considered one of the most promising strategies for this purpose. As a consumable liquid, researchers have studied nanolubricants through the last decade as potential engine oil. Nanolubricants were shown to cause a considerable reduction in the engine frictional and thermal losses, and fuel consumption as well. Despite that, numerous drawbacks regarding the quality of the processed nanolubricants were discerned. This includes the dispersion stability of these fluids and the lack of actual engine experiments. It has been shown that the selection criteria of nanoparticles to be used as lubricant additives for internal combustion engines is considered a complex process. Many factors have to be considered to investigate and follow up with their characteristics. The selection methodology includes tribological and rheological behaviours, thermal stability, dispersion stability, as well as engine performance. Through the last decade, studies on nanolubricants related to internal combustion engines focused only on one to three of these factors, with little concern towards the other factors that would have a considerable effect on their final behaviour. In this review study, recent works concerning nanolubricants are discussed and summarized. A complete image of the designing parameters for this approach is presented, to afford an effective product as engine lubricant.

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“…To study a graphene additive film in n-hexadecane lubricating oil, Zhang et al performed pin-on-disk tests and molecular dynamic studies. It was found that the adsorption of the lubricant could be increased by adding graphene, and shear stresses on the surface were reduced [4]. Wu et al studied graphene oxide nanoplatelets as a lubricant additive for the contact of Si 3 N 4 ceramic/GCr15 steel in a four-ball tester.…”

Section: Introduction 1introduction To Dry Lubricationmentioning

confidence: 99%

Investigation of Graphene Platelet-Based Dry Lubricating Film Formation in Tribological Contacts

Pape

2024

Coatings

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Dry lubricants used in highly loaded rolling bearings are in the focus of current research. In previous studies, graphene platelets applied as dry lubricants on the surfaces of angular contact ball bearings demonstrated superior properties. These specific bearings, experiencing both rolling and spinning motion, create more severe conditions for dry lubricants. To gain deeper insights into the lubrication effects, micro-tribological studies were carried out on the respective film formation and running behavior effects. In the tests, a fixed steel ball slid against an oscillating counterpart under a defined load. During the measurements, the applied load and tangential forces on the ball were recorded to calculate the friction. Comparative investigations included nano-graphite particles and fullerene as dry lubricants, in addition to graphene platelets of various staple thicknesses. To increase the adhesion of the films to the surfaces, a pre-rolling process was implemented. Afterwards, the friction on the compressed films was measured. The results indicate that the pre-rolling process effectively reduces the friction of the system. After testing, the surfaces underwent analysis using laser scanning microscopy to assess the formed films, wear, and material transfer. It has been demonstrated that the pre-rolling process leads to the formation of a very thin compacted film with surface protective properties. With the ball as a counterpart, the graphene platelets generate a transfer film on the contacting surface.

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Molecular dynamics simulation and experimental study on the lubrication of graphene additive films

Cited by 14 publications

References 35 publications

Mechanisms of friction and wear reduction by nanosilver additives to base oil: Molecular dynamics simulation and experimental study

Mechanisms of friction and wear reduction by nanosilver additives to base oil: Molecular dynamics simulation and experimental study

Recent Advances in Preparation and Testing Methods of Engine-Based Nanolubricants: A State-of-the-Art Review

Investigation of Graphene Platelet-Based Dry Lubricating Film Formation in Tribological Contacts

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