Tribological capabilities of chiral nematic liquid crystal additives in mineral motor oil

Mokšin, Vadim

doi:10.1177/1687814020945474

Cited by 6 publications

(6 citation statements)

References 17 publications

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“…Regression modelling is an accepted method of characterizing tribological behaviour. [24][25][26] One of the advantages is that experimental data can be used to make predictions without reference to underlying metallurgical mechanisms. This approach is useful for the mechanical designer who may be interested to use a given material pair in applications.…”

Section: Linear Regression Model Fittingmentioning

confidence: 99%

Modelling the tribological response in dry sliding of boron modified as-cast Ti6Al4V on hardened steel

Choudhury

Prasad

Schueller

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part J:

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Tribological characteristics of boron modified as-cast Ti6Al4V alloys are not very well known, but these alloys enjoy improved as-cast mechanical properties and favourable manufacturing economy. Experimental results are reported here for the effects of sliding speed and normal load on the wear rate and the coefficient of friction in dry sliding of these alloys on hardened EN 31 steel. Alloys having 0%, 0.30%, and 0.55% boron by weight were tested. A full factorial experiment assessed the effects of boron content, speed, and load on wear and friction. Interactions between speed and load were found to be statistically significant in influencing the wear rate and the coefficient of friction. Regression models are developed to predict the wear rate and coefficient of friction responses. The developed contour plots can assist designers in choosing operating conditions when selecting these alloys even if the wear mechanisms are unknown. Evidence shows that the wear resistance of Ti6Al4V can be improved by boron addition, and wear regimes are sensitive to boron content.

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Section: Linear Regression Model Fittingmentioning

confidence: 99%

Modelling the tribological response in dry sliding of boron modified as-cast Ti6Al4V on hardened steel

Choudhury

Prasad

Schueller

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part J:

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“…26,27 Unique schistose molecular structures provide greater shear resistance and are beneficial to form a large oil film when dissolved in oils. 28 The influence of temperature on tribological performance has been reported in several studies. Ermakov et al 29 found that cholesteric liquid crystal displayed the minimum coefficient of friction during the friction tests in the temperature range of mesophase.…”

Section: Introductionmentioning

confidence: 98%

“…Cholesteric liquid crystals can display excellent antifriction and antiwear properties in limited cases, ,, exhibiting different properties with the changes in temperature . Ester group in molecules can help to improve the solubility in oils. , Unique schistose molecular structures provide greater shear resistance and are beneficial to form a large oil film when dissolved in oils . The influence of temperature on tribological performance has been reported in several studies.…”

Section: Introductionmentioning

confidence: 99%

Tribological Properties of Cholesteric Fluorinated Liquid Crystal as Lubricant Additives in PAO4 under Elevated Temperatures

Zhang

Jiang

Gao

et al. 2021

Ind. Eng. Chem. Res.

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A series of fluorinated liquid crystal compounds with perfluoroalkyl chains are reported and their properties as lubrication additives are discussed. The structures were characterized by Fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR), and mass spectrum (MS). The liquid crystalline properties were examined by differential scanning calorimetry (DSC) and polarized optical microscopy (POM), the tribological properties were tested by a universal mechanical tester (UMT), a friction tester, and a 3D optical microscope, and the worn surfaces were analyzed by scanning electron microscopy–energy-dispersive spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS). The results showed that PAO4 with fluorinated liquid crystals (LCs) led to a significant reduction in friction coefficient (30%) and wear (twice over). And the tribological performance was closely related to mesogenic temperature ranges of liquid crystals. The analysis of EDS and XPS indicated that a protective film can be formed of ferric oxide and ferric fluoride. It can be hypothesized that the tribofilm could avoid the direct contact of the rough material on the metal surface on the metal surface, thus reducing friction and wear.

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“…Yang's team [15] reported that 1,3-diketone EPND (1-(4-ethyl phenyl) nonane-1,3-dione), a nematic LC lubricant additive with excellent tribological properties, is particularly suitable for the severe operating conditions of low load and friction. Additionally, Mokshin [16] reported that cholesteryl stearate and fatty acid cholesterol esters LCs were used as lubricant additives. The tribological properties of LCs were evaluated, and the addition of LCs was found to significantly reduce the coefficient of friction (COF).…”

Section: Introductionmentioning

confidence: 99%

Effect of Mesogenic Phase and Structure of Liquid Crystals on Tribological Properties as Lubricant Additives

Jiang²,

Hu³

et al. 2023

Coatings

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To develop a high-performance additive that can meet different operating conditions, three liquid-crystal compounds (LCs) were developed as additives for a base oil. The structures and thermal stabilities of the obtained LCs were characterized by nuclear magnetic resonance (NMR), Fourier transform infrared (FT-IR) spectroscopy, mass spectroscopy (MS), and thermogravimetric analysis (TGA). The effects of mesogenic-phase temperature ranges on tribological properties were analyzed using differential scanning calorimetry (DSC) and polarized optical microscopy (POM). UMT-TriboLab friction and wear tester was used to study the friction-reducing properties of LCs. The width of wear marks was observed by a Con-tour GT-K 3D profiler to illustrate the anti-wear performance of LCs. The friction surface was characterized by scanning electron microscopy (SEM) and Raman spectroscopy. It was demonstrated that, in comparison with the base oil, the addition of LCs caused a remarkable reduction in the coefficient of friction (21.57%) and wear width (31.82%). In addition, LCs show better tribological abilities in the mesogenic-phase temperature ranges. According to the results, we demonstrated that LCs can be used as lubricant additives, especially for several operating conditions under specific temperatures.

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Tribological capabilities of chiral nematic liquid crystal additives in mineral motor oil

Cited by 6 publications

References 17 publications

Modelling the tribological response in dry sliding of boron modified as-cast Ti6Al4V on hardened steel

Modelling the tribological response in dry sliding of boron modified as-cast Ti6Al4V on hardened steel

Tribological Properties of Cholesteric Fluorinated Liquid Crystal as Lubricant Additives in PAO4 under Elevated Temperatures

Effect of Mesogenic Phase and Structure of Liquid Crystals on Tribological Properties as Lubricant Additives

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