Lubrication and Lubricants

Straffelini, Giovanni

doi:10.1007/978-3-319-05894-8_3

Cited by 3 publications

(4 citation statements)

References 17 publications

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“…[19][20][21][22][23] Conversely, conventional lubricant oils depend on polar additives to adhere to surfaces and create a boundary layer. 24 Also, ILs often have high thermal stabilities and low vapour pressures, two very important general properties when developing new lubricants due to the ever increasing pressure to perform at higher temperatures. The first investigation into boundary layer properties for ILs under confinement was performed using a surface forces apparatus (SFA).…”

Section: Introductionmentioning

confidence: 99%

Is the boundary layer of an ionic liquid equally lubricating at higher temperature?

Hjalmarsson

Atkin

Rutland

2016

Phys. Chem. Chem. Phys.

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Atomic force microscopy has been used to study the effect of temperature on normal forces and friction for the room temperature ionic liquid (IL) ethylammonium nitrate (EAN), confined between mica and a silica colloid probe at 25 °C, 50 °C, and 80 °C. Force curves revealed a strong fluid dynamic influence at room temperature, which was greatly reduced at elevated temperatures due to the reduced liquid viscosity. A fluid dynamic analysis reveals that bulk viscosity is manifested at large separation but that EAN displays a nonzero slip, indicating a region of different viscosity near the surface. At high temperatures, the reduction in fluid dynamic force reveals step-like force curves, similar to those found at room temperature using much lower scan rates. The ionic liquid boundary layer remains adsorbed to the solid surface even at high temperature, which provides a mechanism for lubrication when fluid dynamic lubrication is strongly reduced. The friction data reveals a decrease in absolute friction force with increasing temperature, which is associated with increased thermal motion and reduced viscosity of the near surface layers but, consistent with the normal force data, boundary layer lubrication was unaffected. The implications for ILs as lubricants are discussed in terms of the behaviour of this well characterised system.

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Section: Introductionmentioning

confidence: 99%

Is the boundary layer of an ionic liquid equally lubricating at higher temperature?

Hjalmarsson

Atkin

Rutland

2016

Phys. Chem. Chem. Phys.

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“…We included 11 categories of end-use graphite applications: Graphite electrodes which are used in electric arc furnaces that melt scrap and other raw materials. , Refractories that consume magnesia-carbon and alumina-carbon refractory materials to produce steel. , Crucibles, binders, and ingot molds and ladles used at foundries. Four battery categories: primary batteries (single-use batteries), secondary batteries (rechargeable batteries), lithium-ion battery-powered mobile devices and cordless tools, and automotive lithium-ion batteries. Friction-reducing products in vehicles such as brake linings and clutch facings. Carbon products that include carbon brushes, components for electrical purposes, and graphite bearings. Solid lubricants, which typically contain graphite, as it is noninflammable and has high thermal stability, chemical inertness, and thermal conductivity Recarburising in steel production via electric arc furnace to increase the carbon content of steel …”

Section: Methodsmentioning

confidence: 99%

“… Solid lubricants, which typically contain graphite, as it is noninflammable and has high thermal stability, chemical inertness, and thermal conductivity. 58 Recarburising in steel production via electric arc furnace to increase the carbon content of steel. 59 Graphite shapes are purified and micronized graphite is added to metal power mixtures to fabricate sintered parts.…”

Section: Methodsmentioning

confidence: 99%

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Graphite Flows in the U.S.: Insights into a Key Ingredient of Energy Transition

Zhang

Liang

Dunn

2023

Environ. Sci. Technol.

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Demand for graphite will grow with expanding use of lithium-ion batteries in the United States. Much graphite is imported, raising supply chain risks. It is therefore imperative to characterize graphite's sources and sinks. Accordingly, we present the first material flow analysis for natural and synthetic graphite in the U.S. The analysis (for 2018) begins with processed graphite trade and includes graphite production, graphite product trade, manufacturing of end products, end product use, and waste management. It considers 11 end-use applications for graphite, two waste management stages, and three recycling pathways. In 2018, 354 thousand tonnes (kt) of processed graphite were consumed in the U.S., including 60 kt natural graphite and 294 kt synthetic graphite. 145 kt of graphite were traded. Refractories and foundries consumed 56% of natural graphite; 42% of synthetic graphite went into making graphite electrodes. Batteries accounted for 10 and 5% of natural and synthetic graphite consumption, respectively; 78% of total graphite used dissipated into the environment; 22% reached the waste disposal stage of which 71% was landfilled and 29% was recycled; and 59 kt of graphite accumulated in in-use stocks. Recycling more graphite and producing graphite from lignin would favorably influence today's supply chain.

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Impacts of Lubricant Type on the Densification Behavior and Final Powder Compact Properties of Cu–Fe Alloy under Different Compaction Pressures

Korim

Elsayed

2022

Materials

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A Cu–15Fe alloy was fabricated using a powder metallurgy (PM) route, with the addition of different solid lubricants (i.e., paraffin wax (PW) and stearic acid (SA) as well as their composites (PW+SA)). Green compacts were produced via cold compaction at different pressure levels of 50 MPa, 200 MPa, and 350 MPa, then sintered for 60 min under vacuum at 1050 °C. The systematic evolution of the densification, porosity, and pore-size behavior were studied. Vickers Hardness Tests were used to measure hardness. The analysis of the morphological alterations was performed using scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. Moreover, under dry sliding conditions, pin-on-disk wear tests were conducted in order to determine tribological properties such as the coefficient of friction (µ), specific wear rate (K), and friction temperature gain. Results revealed that the lubrication process and compaction pressure play a crucial role in defining the characteristics of the final compact. Higher sintered densities and hardnesses were achieved at 50 MPa when PW was used as a solid lubricant, and became reduced as the compaction pressure increased. In contrast, in the case of SA, higher sintered densities and hardnesses were obtained at a compaction pressure of 350 MPa, and increased with increasing pressure. Moreover, PW samples exhibited lower coefficients of friction and wear properties. The addition of SA improves the wear loss of friction materials as well as their coefficients of friction. Compared to blank and PW samples, SA samples show a nearly 50% reduction in wear rate.

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Lubrication and Lubricants

Cited by 3 publications

References 17 publications

Is the boundary layer of an ionic liquid equally lubricating at higher temperature?

Is the boundary layer of an ionic liquid equally lubricating at higher temperature?

Graphite Flows in the U.S.: Insights into a Key Ingredient of Energy Transition

Impacts of Lubricant Type on the Densification Behavior and Final Powder Compact Properties of Cu–Fe Alloy under Different Compaction Pressures

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