The role of lubricant and carbon surface in achieving ultra- and superlow friction

Weihnacht, Volker; Makowski, Stefan

doi:10.1016/b978-0-444-64313-1.00014-4

Cited by 7 publications

(9 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It interacts with the volume of at least 1 μm into the surface, making it possible to study subsurface volume rehybridization. [ 8 ] The following Raman analyses for both compression rings before and after the tribotest were performed to estimate changes in rehybridization.…”

Section: Resultsmentioning

confidence: 99%

“…However, some authors question that rehybridization is not a mechanism of solid lubrication but rather an accompanying phenomenon of tribological loading. [ 8 ] Nevertheless, a higher degree of rehybridization could impact shear forces resulting from asperity collision. It is known that DLIP microtexturing triggers also rehybridization, not only ablation, thus reducing the remaining sp 3 ‐fraction and making the a‐C coating softer.…”

Section: Resultsmentioning

confidence: 99%

“…[20] 3.6. Raman Spectroscopy to Study C-Structure Particular properties of carbon coatings, such as self-passivation, rehybridization (also called "graphitization") processes, or formation of planar graphene-like structures [8] evocable by tribological loading, may lead to low interfacial shear stresses. To estimate the degree of rehybridization, Raman spectroscopy was used.…”

Section: Mbs/ehd Simulation Details Of the Compression Piston Ringsmentioning

confidence: 99%

“…Hydrogen‐free amorphous carbon (a‐C) and tetrahedral amorphous carbon (ta‐C, predominantly sp 3 ‐hybridization) coatings exhibit properties such as enormous hardness (>40 GPa) as well as high wear resistance and, in combination with special lubricants, show friction‐reducing properties up to superlubricity. [ 8,9 ] The first thin ta‐C films (up to 106 nm film thickness) were patterned by Roch et al [ 10 ] using DLIP. Depending on the applied laser fluence, rehybridization or ablation of the ta‐C layer can occur.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Positive Effect of Periodic Micropatterns on Compression Ring Friction

Michelberger

Schell

Jaitner³

et al. 2023

Adv Eng Mater

View full text Add to dashboard Cite

Internal combustion engines are increasingly regulated in regard to efficiency and environmental impact, which requires advanced optimization strategies of engine components. The contact between the top ring and the cylinder liner is critical to the efficiency of an internal combustion engine. As shown in a previous study, an amorphous carbon coating can greatly improve the friction properties of piston rings. This work expands on these results by fabricating laser‐interference‐induced microchannels on the coating perpendicular to the direction of movement with a mean depth of 0.97 and 3.13 μm spatial period to further optimize the tribology. Fired single‐cylinder engine measurements of the microtextured rings show a significant reduction in mean piston assembly friction of 5% for operation points that are relevant for urban transportation and up to 10% for specific operation points. Subsequent multibody elastohydrodynamic simulations prove that measured friction changes result from the compression ring microtexture. In particular, the microtexture increases the hydrodynamic pressure, reduces hydrodynamic losses, and leads to 20% lowered compression ring losses for an entire combustion cycle of the investigated operation point. In the future, such tribological concepts can be deployed in internal combustion engines that are powered by sustainable hydrogen or methanol.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Mbs/ehd Simulation Details Of the Compression Piston Ringsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Positive Effect of Periodic Micropatterns on Compression Ring Friction

Michelberger

Schell

Jaitner³

et al. 2023

Adv Eng Mater

View full text Add to dashboard Cite

show abstract

“…This is because ta-C coatings have several advantages over established DLC coatings due to their superhardness (>40 GPa), making them extremely wear-resistant. Furthermore, in combination with special lubricants, they can show an extraordinarily low friction, so-called superlubricity [ 3 , 4 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of Energy and Temperature on Tetrahedral Amorphous Carbon Coatings Deposited by Filtered Laser-Arc

et al. 2021

Self Cite

View full text Add to dashboard Cite

In this study, both the plasma process of filtered laser-arc evaporation and the resulting properties of tetrahedral amorphous carbon coatings are investigated. The energy distribution of the plasma species and the arc spot dynamics during the arc evaporation are described. Different ta-C coatings are synthesized by varying the bias pulse time and temperature during deposition. An increase in hardness was observed with the increased overlapping of the bias and arc pulse times. External heating resulted in a significant loss of hardness. A strong discrepancy between the in-plane properties and the properties in the film normal direction was detected specifically for a medium temperature of 120 °C during deposition. Investigations using electron microscopy revealed that this strong anisotropy can be explained by the formation of nanocrystalline graphite areas and their orientation toward the film’s normal direction. This novel coating type differs from standard amorphous a-C and ta-C coatings and offers new possibilities for superior mechanical behavior due to its combination of a high hardness and low in-plane Young’s Modulus.

show abstract

Lubricity of chelated orthoborate-phosphonium ionic liquids on tetrahedral amorphous carbon and steel surfaces

Watanabe

Sasaki

et al. 2023

Journal of Molecular Liquids

View full text Add to dashboard Cite

The role of lubricant and carbon surface in achieving ultra- and superlow friction

Cited by 7 publications

References 47 publications

Positive Effect of Periodic Micropatterns on Compression Ring Friction

Positive Effect of Periodic Micropatterns on Compression Ring Friction

Effect of Energy and Temperature on Tetrahedral Amorphous Carbon Coatings Deposited by Filtered Laser-Arc

Lubricity of chelated orthoborate-phosphonium ionic liquids on tetrahedral amorphous carbon and steel surfaces

Contact Info

Product

Resources

About