High dispersivity and excellent tribological performance of titanate coupling agent modified graphene oxide in hydraulic oil

Li, Xiaopeng; Gan, Chaoliang; Han, Zeyong; Yan, Han; Chen, Duoli; Li, Wen; Li, Hao; Fan, Xiaoqiang; Li, Dongshan; Zhu, Minhao

doi:10.1016/j.carbon.2020.04.038

Cited by 54 publications

(18 citation statements)

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“…Aggregation reduces the effective particle concentration and prevents nanoparticles from entering the friction interfaces. Many research efforts have been directed toward producing stable well-dispersed additives, and many previous studies using GO have concluded that high-dispersible GO-dispersed oil is better for low friction. ,,− …”

Section: Introductionmentioning

confidence: 99%

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Low Friction of Graphene Oxide Aggregates in Lubricant Oil between a Steel Ball and Glass Disk under Boundary Lubrication

et al. 2022

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Previously, isolated nanocarbons in lubricating oils were considered essential for good lubrication. However, we observed that graphene oxide (GO) aggregates in lubricating oil have lower frictional properties than isolated dispersed GO. The GO was dispersed in polyα-olefin (PAO) using alkylamine at different ratios of GO and alkylamine, or it was heated at different temperatures to synthesize high- and low-dispersible GO-dispersed PAO. X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy measurements showed that low-dispersible modified GOs retained many of the original GO chemical and structural features. Macrotribological tests between a steel ball and glass disk in GO-dispersed oil were conducted with a load of 5 N under boundary lubrication. The friction interface was observed in situ using an optical microscope. In the low-dispersible GO-dispersed PAO, many GO aggregates were observed through optical microscopy. Surprisingly, the friction coefficients decreased when the GO aggregates entered the friction interface and covered the contact area. The low-dispersible GO-dispersed PAO using alkylamine had the lowest friction coefficient of 0.05, as the GO aggregates covered the contact area. From microtribological tests with a load of 0.8 mN as well, it is assumed that the low friction of the GO aggregates originates due to the sliding between the weakest shear layers in the aligned multiple GO layers.

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Section: Introductionmentioning

confidence: 99%

“…Many researchers have investigated the tribological properties of graphene oxide (GOs) as additives in water and lubrication oil. − Although the size of the GO can exceed 10 μm, its thickness is less than 1 nm. Thus, it is considered to enter narrow friction interfaces under boundary lubrication.…”

Section: Introductionmentioning

confidence: 99%

Low Friction of Graphene Oxide Aggregates in Lubricant Oil between a Steel Ball and Glass Disk under Boundary Lubrication

et al. 2022

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“…Nanomaterials that display superior mechanical properties, thermal stability, and high specific area have been widely employed as high-performance additives. − For instance, Qu et al revealed that the SiO 2 spherical nanoparticle can behave as rolling elements at local asperities and form a boundary film that can support load and decrease interfacial friction. , Besides, graphene, as a newly emerged two-dimensional nanomaterial, can also be employed as an effective additive. ,− It is reported that the graphene layers can slide again each other easily under high shear stress because of the low van der Waals force between interlayers. − Furthermore, graphene can support a high load due to its strong strength in the vertical direction. , Thus, it exhibits excellent friction-reducing and antiwear performance when used as an additive. However, there are two essential issues to be addressed when these nanomaterials are used as lubricant additives.…”

Section: Introductionmentioning

confidence: 99%

Tribological Performance of an Imidazolium Ionic Liquid-Functionalized SiO₂@Graphene Oxide as an Additive

Song

Yan

2021

ACS Appl. Mater. Interfaces

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A graphene oxide (GO)-wrapped SiO2 nanosphere was modified with a 1-methylimidazolium bis(salicylato)borate (MEIMBScB) ionic liquid to form a SiO2@GO@MEIMBScB nanocomposite. The SiO2@GO@MEIMBScB nanocomposite exhibited a core–shell structure, which was characterized by Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, photoluminescence spectroscopy, dynamic light scattering, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The SiO2@GO@MEIMBScB nanocomposite was dispersed into poly(ethylene glycol) 400 (PEG400) as a lubricant additive, and its tribological performance was evaluated with a four-ball tribometer under 392 N at 1450 rpm for 30 min. The results showed that the SiO2@GO@MEIMBScB nanocomposite can reduce the friction coefficient by 57.27% and reduce the wear scar diameter by 16.98% at an optimized concentration. Its tribological performance was much better than the individual SiO2@GO and MEIMBScB ionic liquid and the SiO2@GO/MEIMBScB mixture. The SiO2@GO@MEIMBScB nanocomposite exhibited a synergistic effect, which was confirmed by surface analysis on a wear track. It showed that SiO2@GO@MEIMBScB can be adsorbed on the rubbing surface and form a tribo-boundary film to reduce friction and wear. A possible lubrication mechanism was proposed, which might guide the development of a novel nanolubricant additive.

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“…The graphene structure can be combined with other chemical structures via chemical structure. A previous study modified graphene using octadecylamine and dicyclohexylcarbodiimide [19], alkyl structure [20], and a titanate coupling agent [21]. Another method is by adding surfactants, which are an easier solution.…”

Section: Introductionmentioning

confidence: 99%

Synergistic Behavior of Graphene and Ionic Liquid as Bio-Based Lubricant Additive

et al. 2021

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The constant utilization of petroleum-based products has prompted concerns about the environment, hence a replacement for these products must be explored. Biolubricants are a suitable replacement for petroleum-based lubricants as they provide better lubricity. Biolubricant performance can be improved by the addition of graphene. However, there are reports that graphene is unable to form a stable suspension for a long period. This study used a graphene-ionic liquid additive combination to stabilize the dispersion in a biolubricant. Graphene and ionic liquid were dispersed into the biolubricant via a magnetic stirrer. The samples were tested using a high frequency reciprocating rig. The cast iron sample was then further observed using various techniques to determine the lubricating mechanism of the lubricant. Different dispersion stability of graphene was observed for different biolubricants, which can be improved with ionic liquids. All ionic liquid samples maintained an absorbance value of three for one month. The utilization of ionic liquid was also able to decrease the frictional performance by 33%. Further study showed that by using the ionic liquid alone, the frictional could only reduce the friction coefficient by 13% and graphene could only reduce the friction by 7%. A smooth worn surface scar can be seen on the graphene-IL sample compared to the prominent corrosive spot on the IL samples and abrasive scars on graphene samples. This indicates synergistic behavior between the two additives. It was found that the ionic liquid does not only improve the dispersion stability, but also plays a role in forming the tribolayer.

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High dispersivity and excellent tribological performance of titanate coupling agent modified graphene oxide in hydraulic oil

Cited by 54 publications

References 40 publications

Low Friction of Graphene Oxide Aggregates in Lubricant Oil between a Steel Ball and Glass Disk under Boundary Lubrication

Low Friction of Graphene Oxide Aggregates in Lubricant Oil between a Steel Ball and Glass Disk under Boundary Lubrication

Tribological Performance of an Imidazolium Ionic Liquid-Functionalized SiO₂@Graphene Oxide as an Additive

Synergistic Behavior of Graphene and Ionic Liquid as Bio-Based Lubricant Additive

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High dispersivity and excellent tribological performance of titanate coupling agent modified graphene oxide in hydraulic oil

Cited by 54 publications

References 40 publications

Low Friction of Graphene Oxide Aggregates in Lubricant Oil between a Steel Ball and Glass Disk under Boundary Lubrication

Low Friction of Graphene Oxide Aggregates in Lubricant Oil between a Steel Ball and Glass Disk under Boundary Lubrication

Tribological Performance of an Imidazolium Ionic Liquid-Functionalized SiO2@Graphene Oxide as an Additive

Synergistic Behavior of Graphene and Ionic Liquid as Bio-Based Lubricant Additive

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Tribological Performance of an Imidazolium Ionic Liquid-Functionalized SiO₂@Graphene Oxide as an Additive