Synergistic Effect Between Phosphonium-Based Ionic Liquid and Three Oxide Nanoparticles as Hybrid Lubricant Additives

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
M. Upendra ◽  
V. Vasu

Abstract The tribological properties of ionic liquid (IL) trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate along with Al2O3, CuO, and SiO2 nanoparticles (NPs) have been investigated as a lubricant additive in a group 1 mineral base oil. About 0.5 wt% concentration of additives were added in base oil, and tribological tests were conducted at mild (stipulated) and severe (ASTM D 4172D) working conditions to assess the synergy between IL and NPs. This study shows the excellent synergy between IL, Al2O3, and CuO NPs in improving tribological and extreme pressure (EP) properties. Al2O3 and CuO hybrid nanolubricants decreased friction by 19% and 24%, whereas wear by 32% and 36%, respectively, at ASTM test conditions. IL displayed very good EP properties with a total improvement of 19%, and the highest load-bearing capacity was observed for Al2O3 and CuO hybrid nanolubricants with an improvement of 30% and 34%, respectively. No conclusive evidence of synergy has been observed between IL and SiO2 NPs. Surface characterization techniques, such as scanning electron microscope, energy dispersive X-ray spectrometer, and Raman spectra, demonstrated the formation of a tribofilm rich in phosphate and tribosintered NPs on the worn surface responsible for improved triboperformances.

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
A. Z. Syahir ◽  
M. H. Harith ◽  
N. W. M. Zulkifli ◽  
H. H. Masjuki ◽  
M. A. Kalam ◽  
...  

Abstract This study reports the tribological characteristics of trimethylolpropane trioleate (TMPTO) additivated with antifriction and antiwear additives, which are ionic liquid (IL), glycerol monooleate (GMO), and molybdenum dithiocarbamate (MoDTC). In addition, to obtain the ideal composition that results in the minimal coefficient of friction (COF), optimization tool was employed using response surface methodology (RSM) technique with the Box–Behnken design. The IL used in this study was a phosphorus-type IL, namely trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl) phosphinate, [P14,6,6,6][TMPP]. The resulting COF and worn surface morphology were investigated using high-frequency reciprocating rig (HFRR) tribotester and scanning electron microscope with energy-dispersive X-ray spectroscopy (SEM-EDX), respectively. From the experimental results, a second-order polynomial mathematical model was constructed and able to statistically predict the resulting COF. The optimized values that resulted in the lowest average COF of 0.0458 were as follows: 0.93 wt% IL, 1.49 wt% GMO, and 0.52 wt% MoDTC. The addition of IL into neat base oil managed to reduce the COF, while the combination of IL, GMO, and MoDTC at optimum concentration further reduced the average COF and wear as observed through SEM micrographs when compared with those of additive-free TMPTO, suggesting that GMO and MoDTC were compatible to be used with IL.


Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 922 ◽  
Author(s):  
Binbin Wang ◽  
Zhaodong Zhong ◽  
Han Qiu ◽  
Dexin Chen ◽  
Wei Li ◽  
...  

Natural serpentine powders are applicable as additives for various lubricating oils. However, no uniform theories explain their tribological performance, lubrication, and wear mechanism, especially their self-repairing mechanism. Herein, the influence of different nano serpentine powders (NSPs) contents in liquid paraffin on the friction and wear characteristics of steel balls and the self-repairing process of NSPs on the worn surface were studied. Results show that the optimal amount of NSPs was 0.5 wt %. Relative to those of the base oil, the friction coefficients and wear spot diameters were reduced by 22.8% and 34.2%, respectively. Moreover, the long-term tribological test shows that the wear scar diameter decreased slightly after 3 h, reaching the state of dynamic balance between wear and repair. The outstanding tribological performance should be attributed to the formed bilayer tribofilm, the first layer of which contains nanoparticles surrounded by lubricants and the second layer of which contains nanoparticles compacted onto the surface of the steel ball.


Lubricants ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 46
Author(s):  
Muhammad Harith Hasnul ◽  
Nurin Wahidah Mohd Zulkifli ◽  
Masjuki Hassan ◽  
Syahir Amzar Zulkifli ◽  
Mohd Nur Ashraf Mohd Yusoff ◽  
...  

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.


Author(s):  
Aswani K Singh ◽  
Varun Sharma

During machining, the cutting fluids play an essential role in cooling and lubrication. In order to reduce the friction forces, the excessive amount of the cutting fluids are generally used. This, in turn, leads to wastage of the cutting fluids which results in a serious impact on the environment, health and cost of production. Therefore, the judicious use of lubricants is the foremost concern in the manufacturing industry. In order to mitigate these drawbacks, various alternatives have been developed in the last decade. In the present paper, ionic liquids have been proved as favourable sustainable alternative additives in the base oil. The effect of alkyl chain length of ionic liquids with base oil on the thermo-physical and tribological characteristics of cutting fluids including viscosity, wettability, anticorrosion behaviour, thermal stability, and coefficient of friction have been analysed. In the present study, pyrrolidinium and hexafluoro-phosphate (PF6) have been used as cation and anion, respectively, with rice bran oil as base oil. The five different ionic liquids have been dispersed in base oil by 1.0 wt%. It has been found that longer alkyl chain length showed the favourable results as compared to the shorter one. Results indicated that ionic liquid based cutting fluid attained ample enhanced thermophysical and tribological properties as compared to the neat rice bran oil. There has been 5.08% and 4.29% improvement in viscosity and thermal conductivity for IL4 + RBO in comparison to neat RBO. In addition, the wettability, coefficient of friction, and wear volume have been reduced by 20.34%, 53.79% and 57.87% correspondingly.


2021 ◽  
pp. 1-17
Author(s):  
Neha Singh ◽  
Sujeet K Sinha

Abstract Liquid absorption and tribological studies of epoxy-based composite with ultra-high molecular weight polyethylene (UHMWPE) and MoS2, sliding against steel were conducted. Composites, as coating and as a bulk, were soaked in water, base oil, ionic liquid and lithium-based grease for different intervals of days or months. Liquid weight% gain was more in polar liquids when compared to non-polar. Coated composite soaked in grease for 10 days showed coefficient of friction of 0.08 with wear-life of more than 1 million cycles and wear rate of 1.7×10−8 mm3/Nm. Bulk polymer composite soaked in grease for 180 days provided the least coefficient of friction of 0.06 and specific wear rate of 2.60×10−7 mm3/Nm.


Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 713 ◽  
Author(s):  
Hong Guo ◽  
Angela Rina Adukure ◽  
Patricia Iglesias

Friction and wear of sliding surfaces are responsible for important energy losses and negative environmental effects. The use of environmentally friendly and cost-effective protic ionic liquids as neat lubricants and lubricant additives has the potential to increase the efficiency and durability of mechanical components without increasing the environmental damage. In this work, three halogen-free protic ionic liquids with increasing extent of ionicity, 2-hydroxyethylammonium 2-ethylhexanoate, 2-hydroxymethylammonium 2-ethylhexancate, and 2-hydroxydimethylammonium 2-ethylhexanoate, were synthesized and studied as neat lubricants and additives to a biodegradable oil in a steel–steel contact. The results show that the use of any protic ionic liquid as a neat lubricant or lubricant additive reduced friction and wear with respect to the biodegradable oil. The ionic liquid with the lowest ionicity reached the highest wear reduction. The one possessing the highest ionicity presented the poorest friction and wear behaviors as a neat lubricant, probably due to the more ionic nature of this liquid, which promoted tribocorrosion reactions on the steel surface. This ionic liquid performed better as an additive, showing that a small addition of this liquid in a biodegradable oil is enough to form protective layers on steel surfaces. However, it is not enough to accelerate the wear process with detrimental tribocorrosion reactions.


2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Marlene Bartolomé Sáez ◽  
Antolin E. Hernández Battez ◽  
Jorge Espina Casado ◽  
José L. Viesca Rodríguez ◽  
Alfonso Fernández-González ◽  
...  

Purpose The purpose of this paper is to study the antifriction, antiwear and tribolayer formation properties of the trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate ionic liquid (IL) as additive at 1 wt.% in two base oils and their mixtures, comparing the results with those of a commercial oil. Design/methodology/approach The mixture of the base oils used in the formulation of the commercial oil SAE 0W20 plus the IL was tested under rolling/sliding and reciprocating conditions to determine the so-called Stribeck curve, the tribolayer formation and the antifriction and antiwear behaviors. Findings The use of this IL as additive in these oils does not change their viscosity; improves the antifriction and antiwear properties of the base oils, making equal or outperforming these properties of the SAE 0W20; and the thickness and formation rate of the tribolayer resulting from the IL-surface interaction is highly dependent on the type of base oil and influence on the friction and wear results. Originality/value The use of this IL allows to replace partial or totally commercial antifriction and antiwear additives. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2020-0179/


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