Current and Future Trends in Grease Lubrication

Rawat, Sooraj Singh; Harsha, A. P.

doi:10.1007/978-981-15-0434-1_9

Cited by 25 publications

(8 citation statements)

References 63 publications

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“…Considering the physicochemical properties of the SN-150 lube base oil, the roughness of steel balls, and applied load, the film thickness between the steel balls is estimated to be 21.5 nm based on the Hamrock–Dowson theory, and it signified the boundary lubrication regime. , The contact pressure between the steel balls is very crucial, and it governs the role of nanomaterials in the enhancement of tribological properties. The maximum contact pressure between steel balls is estimated based on Hertzian contact theory Herein, P max is the maximum contact stress or Hertzian stress between the steel balls, F N is the effective load, a is the radius of the contact area of steel ball, R ′ is the effective radius, and E ′ is the reduced Young’s modulus. F N , R ′, and E ′ are defined as In the four-ball contact geometry, the applied load ( W ) is distributed over the three stationary balls and the effective load ( F N ) on each ball is estimated by eq .…”

Section: Resultsmentioning

confidence: 99%

Structural-Defect-Mediated Grafting of Alkylamine on Few-Layer MoS₂ and Its Potential for Enhancement of Tribological Properties

Kumari

Chouhan

Sharma

et al. 2020

ACS Appl. Mater. Interfaces

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Two-dimensional transition-metal dichalcogenides possess inherent structural characteristics that can be harnessed for enhancement of tribological properties by making them dispersible in lube media. Here, we present a hydrothermal approach to preparing MoS2 nanosheets comprising 4–10 molecular lamellae. A structural-defect-mediated route for grafting of octadecylamine (ODA) on MoS2 nanosheets is outlined. The unsaturated d orbitals of Mo at the sulfur vacancies on the MoS2 surface are coupled with the electron-rich nitrogen center of ODA and yield ODA-functionalized MoS2 (MoS2–ODA). The MoS2–ODA nanosheets exhibit good dispersibility in lube base oil and are used as an additive (optimized dose: 0.1 mg·mL–1) to mineral oil. It is shown that even at low concentration, MoS2–ODA nanosheets significantly reduce the friction (48%) and wear (44%). Microscopy (field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM)) and spectroscopy (Raman and elemental mapping) analyses of worn scars revealed the formation of MoS2-based protective thin films for lowering of friction and wear. This work, therefore, presents a pathway for low-friction lubricants by deploying functionalized low-dimensional material systems.

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Section: Resultsmentioning

confidence: 99%

Structural-Defect-Mediated Grafting of Alkylamine on Few-Layer MoS₂ and Its Potential for Enhancement of Tribological Properties

Kumari

Chouhan

Sharma

et al. 2020

ACS Appl. Mater. Interfaces

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“…The tribopair made a non-conformal contact, with a Hertzian contact stress (P max ) of 3.4 GPa at contact point. 35…”

Section: Physicochemical and Tribological Characterisation Of Greasesmentioning

confidence: 99%

“…The fibrous network formed by thickener entraps the base oil via Van der Walls and capillary interactions. 35,57 The thickener and base oil both contributed to the formation of a protective tribo-film. However, during the friction process, the temperature may rise due to the collision of asperity or high Hertzian stress ($3.4 GPa), which has caused the degradation of grease and bleeding of base oil from the fibrous structure.…”

Section: Extreme Pressure (Ep) Performance Of Greasesmentioning

confidence: 99%

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Tribological evaluation of PAO 100 oil‐based lithium greases with chemically functionalized nanoadditives

Kumar

Harsha

Rawat

2023

Lubrication Science

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The lubricating greases employed in this study were formulated with polyalphaolefin (PAO) 100 as the base oil and 12‐lithium hydroxystearate as the thickener. The sol–gel method was used to produce the LaF3 nanoadditives. The oleic acid‐treated LaF3 (i.e., OA‐LaF3) and carboxylic acid‐treated MWCNTs (i.e., COOH‐MWCNTs) were blended in the formulated grease samples and used as nanoadditives. The detailed microstructural and chemical properties of chemically treated nanoadditives were investigated using HR‐TEM, XRD, FTIR and XPS analyses. Using a four‐ball tester, the effect of different concentrations of nanoadditives on the tribo‐performance of greases was investigated. Tribo‐test results revealed the role of nanoadditives in PAO‐based grease lubrication performance. COOH‐MWCNTs and OA‐LaF3 nanoadditives outperformed PAO grease in terms of physicochemical and tribo‐performance for steel‐steel tribo‐pair. The improved tribo‐performance is attributed to the formation of tribo‐film on the contact interfaces via nanoadditives. The development of tribo‐film was confirmed by XPS analysis of worn surfaces.

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“…Be it automatic stepped transmission (AT), continuously variable transmission (CVT), or the dual-clutch transmission (DCT), the transmission fluid has the same broad purpose, that is, to create hydraulic pressure, dissipate heat, and protect the metal gears and other parts from wear (Beckman, 2019). The main role of grease in an automotive is to reduce frictional losses by lubricating bearings, i.e., most of the moving parts of the assembly (Rawat and Harsha, 2019). But along with the developments in automobile industries, the lubricants need to perform in harsh conditions and provide various performance and compatibility aspects (Soni and Singh Prajapati, 2017).…”

Section: Lubricants and Their Uses In Vehiclesmentioning

confidence: 99%

Performance Characteristics of Lubricants in Electric and Hybrid Vehicles: A Review of Current and Future Needs

et al. 2020

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Electric and hybrid vehicles are gaining increasing attention in recent years. The distinguished difference between electric/hybrid vehicles from conventional ones is the intermittent on-and-off control of the internal combustion engine, whereas the electric vehicles operate on electrical motors. This difference creates new requirements in lubricants with performance characteristics that are otherwise uncritical: electrical properties (such as electrical conductivity and breakdown voltage) and thermal properties (thermal conductivity, specific heat, among others), in addition to fluidic performance that we have studied for decades. In this review, we discuss about lubricants for electric and hybrid vehicles in the following aspects. Starting with a brief historic review, we gathered information about current needs and challenges in electric and hybrid vehicles. We then compared the properties of lubricants, followed by the performance difference of those vehicles in terms of frictional performance, thermal management, and dielectric breakdown. Performance parameters are critically dependent on the properties of lubricants that are crucial for energy efficiency and reliability. This review can be used as a guidance for the future design of advanced lubricants for electric and hybrid vehicles.

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Current and Future Trends in Grease Lubrication

Cited by 25 publications

References 63 publications

Structural-Defect-Mediated Grafting of Alkylamine on Few-Layer MoS₂ and Its Potential for Enhancement of Tribological Properties

Structural-Defect-Mediated Grafting of Alkylamine on Few-Layer MoS₂ and Its Potential for Enhancement of Tribological Properties

Tribological evaluation of PAO 100 oil‐based lithium greases with chemically functionalized nanoadditives

Performance Characteristics of Lubricants in Electric and Hybrid Vehicles: A Review of Current and Future Needs

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Current and Future Trends in Grease Lubrication

Cited by 25 publications

References 63 publications

Structural-Defect-Mediated Grafting of Alkylamine on Few-Layer MoS2 and Its Potential for Enhancement of Tribological Properties

Structural-Defect-Mediated Grafting of Alkylamine on Few-Layer MoS2 and Its Potential for Enhancement of Tribological Properties

Tribological evaluation of PAO 100 oil‐based lithium greases with chemically functionalized nanoadditives

Performance Characteristics of Lubricants in Electric and Hybrid Vehicles: A Review of Current and Future Needs

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Product

Resources

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Structural-Defect-Mediated Grafting of Alkylamine on Few-Layer MoS₂ and Its Potential for Enhancement of Tribological Properties

Structural-Defect-Mediated Grafting of Alkylamine on Few-Layer MoS₂ and Its Potential for Enhancement of Tribological Properties