Lubrication

Mate, C. Mathew; Carpick, Robert W.

doi:10.1093/oso/9780199609802.003.0009

Cited by 16 publications

(29 citation statements)

References 1 publication

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“…In contrast, the COF of [Bmim][NTf 2 ] decreased from 0.320 ± 0.003 at the thickness of 0.65 nm to a minimum value of 0.167 ± 0.008 at the thickness of 2.10 nm, which is approximately 11% higher than the level-off COF of FIL. Unlike hydrodynamic lubrication, the lubrication using the molecular-level FIL films in microdevices is defined as boundary lubrication, where the chemical structure of the nanometer-thick lubricants is the most critical factor to the adhesion and the friction. ,, The adhesion in nanotribology is governed by the van der Waals force, and the Hamaker constant ( A H ) characterizes the intermolecular force . Because of the presence of the highly fluorinated alkyl chain with low polarizability, the FIL boundary lubricant with low surface tension has a low A H and consequently results in a low adhesion and friction compared to the commercially available IL boundary lubricants.…”

Section: Resultsmentioning

confidence: 99%

Highly Fluorinated Ionic Liquid Films as Nanometer-Thick Media Lubricants for Hard Disk Drives

Wang

Moran

Tang

et al. 2020

ACS Appl. Nano Mater.

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Ionic liquids (ILs) are promising candidates for the nextgeneration nanometer-thick lubricants in hard disc drives (HDDs) because of their excellent physiochemical properties and low monolayer (ML) thicknesses. However, the commercially available ILs have higher surface tension and higher friction than the state-of-the-art perfluoropolyether (PFPE) lubricant. In the current study, a fluorinated IL (FIL) lubricant, which contains cations with highly fluorinated alkyl chains, has been successfully synthesized. The surface tension of FIL is comparable to that of PFPE, which is ideal for enhancing the tribological performance of the FIL lubricant. The thermogravimetric analysis results showed that FIL has higher thermal stability than PFPE Ztetraol. Atomic force microscopy revealed that because of the intrinsically smaller molecular size of FIL, the ML thickness is only ∼50% of that of Ztetraol, which is expected to induce a lower lubricant thickness and higher areal density. Compared to the commercially available ILs, reduced friction of the nanometerthick FIL lubricant on carbon overcoat was also achieved because of its intrinsically lower surface tension. Our results demonstrate that FIL has great potential for application as the next-generation media lubricant in HDDs.

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Section: Resultsmentioning

confidence: 99%

Highly Fluorinated Ionic Liquid Films as Nanometer-Thick Media Lubricants for Hard Disk Drives

Wang

Moran

Tang

et al. 2020

ACS Appl. Nano Mater.

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“…Wedeven Associates is a tribology research and engineering consulting firm. Tribology is the science of friction, lubrication, and wear associated with surfaces in relative motion (Mate & Carpick, 2019). We, humans, experience tribology in action every day.…”

Section: Wedeven Associates: Bringing Tribology Theory To Applicationmentioning

confidence: 99%

Wedeven Associates: Finding New Ways to Develop Novel Solutions to Persistent, Intractable Problems

Jonsen

2021

Entrepreneurship Education and Pedagogy

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Wedeven Associates is a small tribology research and engineering consulting firm located near Philadelphia, Pennsylvania. The company faced a variety of challenges associated with the COVID-19 pandemic as did most small businesses in 2020. As the company became fully operational again, Wedeven Associates was approached by a longtime client to solve a tribological problem the client’s engineers had been trying to address for many years. The catch: Wedeven Associates only had a little over 2 months to do the work while complying with pandemic-related travel and meeting restrictions. This case tells the story of how the Wedeven Associates team met the challenge using virtual tools and a collaborative approach built on first principles. Readers are introduced to “tribology” as an engineering discipline and “first principles” as a problem-solving approach.

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“…This loss of energy is severed in the case of high-speed micro-scale lubricated tribo-contacts. The development of such lubricated contacts is restricted due to the higher magnitude of friction-force (Mate and Carpick, 2019). So, it is important to think and find a suitable solution for this critical issue.…”

Section: Introductionmentioning

confidence: 99%

Investigating the effect of different slip zone locations on the lubrication performance of textured journal bearings

Arif

Kango

Shukla

2021

ILT

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Purpose This study aims to purpose the suitable location of slip boundary condition and microscale surface textures to enhance the tribological performance of the hydrodynamic journal bearings. Design/methodology/approach Mass conserving Elrod cavitation algorithm with considering slip boundary condition has been used for predicting the static performance characteristics (load carrying capacity, coefficient of friction and volumetric inflow rate) of finite cylindrical shape textured journal bearings. Findings It has been observed that the full textured bearing with slip boundary condition in between 0°–180° circumferential region gives a significant reduction in the lubricant rupture zone. However, the introduction of textures up to the interface of slip and the no-slip region is increasing the load-carrying capacity and reduces the shear stress. This reduction in shear stress with combined slip and surface textures is effective in increasing the volumetric inflow rate of the lubricant. Practical implications The combined effect of slip boundary condition and surface texturing is increasing the scope of liquid lubricants in hydrodynamic journal bearings and further contributing toward the development of small-scale rotating machines. Originality/value The study related to the use of mass conserving Elrod cavitation algorithm for finding the optimum location of slip and surface texture zones has been found rare in the literature. Previous studies show that the mass conserving Elrod cavitation algorithm gives realistic results for textured bearings and its findings show good agreement with the experimental observations.

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Lubrication

Cited by 16 publications

References 1 publication

Highly Fluorinated Ionic Liquid Films as Nanometer-Thick Media Lubricants for Hard Disk Drives

Highly Fluorinated Ionic Liquid Films as Nanometer-Thick Media Lubricants for Hard Disk Drives

Wedeven Associates: Finding New Ways to Develop Novel Solutions to Persistent, Intractable Problems

Investigating the effect of different slip zone locations on the lubrication performance of textured journal bearings

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