Perspectives of friction mechanism of a-C:H film in vacuum concerning the onion-like carbon transformation at the sliding interface

Song, Hui; Li, Ji; Li, Hongxuan; Liu, Xiaohong; Zhou, Hang; Wang, Weiqi; Chen, Jianmin

doi:10.1039/c4ra16348f

Cited by 31 publications

(11 citation statements)

References 33 publications

(34 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, its contribution to the sharp drop in friction during the running-in process can be ruled out. Similar phenomena were reported in other studies [31,32,33].…”

Section: Discussionsupporting

confidence: 92%

Key Role of Transfer Layer in Load Dependence of Friction on Hydrogenated Diamond-Like Carbon Films in Humid Air and Vacuum

et al. 2019

View full text Add to dashboard Cite

The friction of hydrogenated diamond-like carbon (H-DLC) films was evaluated under the controlled environments of humid air and vacuum by varying the applied load. In humid air, there is a threshold applied load below which no obvious friction drop occurs and above which the friction decreases to a relatively low level following the running-in process. By contrast, superlubricity can be realized at low applied loads but easily fails at high applied loads under vacuum conditions. Further analysis indicates that the graphitization of the sliding H-DLC surface has a negligible contribution to the sharp drop of friction during the running-in process under both humid air and vacuum conditions. The low friction in humid air and the superlow friction in vacuum are mainly attributed to the formation and stability of the transfer layer on the counterface, which depend on the load and surrounding environment. These results can help us understand the low-friction mechanism of H-DLC film and define optimized working conditions in practical applications, in which the transfer layer can be maintained for a long time under low applied load conditions in vacuum, whereas a high load can benefit the formation of the transfer layer in humid air.

show abstract

“…Thus, its contribution to the sharp drop in friction during the running-in process can be ruled out. Similar phenomena were reported in other studies [31,32,33].…”

Section: Discussionsupporting

confidence: 92%

Key Role of Transfer Layer in Load Dependence of Friction on Hydrogenated Diamond-Like Carbon Films in Humid Air and Vacuum

et al. 2019

View full text Add to dashboard Cite

show abstract

“…The relative intensity ratio of these two peaks (I D /I G ) can be used to characterize the graphitization degree. Normally, larger value of I D /I G corresponds to a higher graphitization degree [37]. Figure 5 compares the Raman spectra measured on the worn surfaces of H-DLC films.…”

Section: Role Of Graphitization Of Dlc Materials Beneath the Worn Surfmentioning

confidence: 99%

Perspectives of the Friction Mechanism of Hydrogenated Diamond-Like Carbon Film in Air by Varying Sliding Velocity

et al. 2018

View full text Add to dashboard Cite

The purpose of the present work is to probe the friction mechanism of hydrogenated diamond-like carbon (H-DLC) film in air by varying sliding velocity (25-1000 mm/s). Friction tests of Al 2 O 3 ball against H-DLC film were conducted with a rotational ball-on-disk tribometer. As the sliding velocity increases, both the friction coefficient and the surface wear of H-DLC film decrease, reach the minimum values, and then increase in the high sliding velocity region. Based on the observed results, three main friction mechanisms of H-DLC film-namely graphitization mechanism, transfer layer mechanism, and passivation mechanism-are discussed. Raman analysis indicates that the graphitization of worn surface on the H-DLC film has a negligible contribution to the variation of the friction coefficient and the surface wear. The origin of the sliding velocity dependence is due to the synergistic interaction between the graphitized transfer layer formation and the surface passivation. The present study will not only enrich the understanding of friction mechanism of H-DLC films in air, but will also help to promote their practical engineering applications.

show abstract

“…Wang et al 17 found that the curved 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 4 graphitic structure in fullerene-like hydrogenated carbon film is beneficial for achievement of low friction. Quite recently, Song et al 18 found that instead of existing in as-prepared a-C:H films, lubricious onion-like structure can be spontaneously formed at the sliding interface, which could account for the extremely low friction coefficient. These layered structures may lead to superlubricity due to possible interlayer sliding.…”

Section: Introductionmentioning

confidence: 99%

Combined Effects of Structural Transformation and Hydrogen Passivation on the Frictional Behaviors of Hydrogenated Amorphous Carbon Films

Chen

et al. 2015

J. Phys. Chem. C

View full text Add to dashboard Cite

Tribological behaviors of hydrogenated amorphous carbon (a-C:H) films under single asperity contact are investigated by molecular dynamics (MD) simulations. Hydrogen concentration and normal load are found to play essential roles in the frictional behavior of a-C:H films. With low hydrogen concentration, the a-C:H film shows high adhesion and friction even at very low normal loads (1.75 nN). The sp 3 -to-sp 2 rehybridization is observed in the a-C:H films with all studied hydrogen concentrations, which is greatly enhanced with increasing normal load. At high normal loads, formation of nanocrystalline graphene-like lamellar structures is observed locally, usually beneath the instantaneous contact area, acting as a lubricating agent, demonstrating local graphitization due to combined effects of the compression and shear process. With high hydrogen concentration, the friction shows a linear increase along with the normal load and higher load bearing capability. Hydrogen atoms accumulate on the film surface during the sliding process, reducing friction significantly.Hydrogen passivation becomes more obvious with higher hydrogen content especially at low normal loads, where a hydrogen-rich monolayer is found to attach onto the asperity, functioning as a lubricating transfer layer. This work shows the combined effects of structural transformation and surface passivation on the frictional behaviors of a-C:H films, and may shed light on the well-known but not well-understood superlubricity mechanism of a-C:H films.

show abstract

Perspectives of friction mechanism of a-C:H film in vacuum concerning the onion-like carbon transformation at the sliding interface

Abstract: A-C:H films with low friction and good wear resistance have long been regarded as a potential space lubricating film.

Cited by 31 publications

References 33 publications

Key Role of Transfer Layer in Load Dependence of Friction on Hydrogenated Diamond-Like Carbon Films in Humid Air and Vacuum

Key Role of Transfer Layer in Load Dependence of Friction on Hydrogenated Diamond-Like Carbon Films in Humid Air and Vacuum

Perspectives of the Friction Mechanism of Hydrogenated Diamond-Like Carbon Film in Air by Varying Sliding Velocity

Combined Effects of Structural Transformation and Hydrogen Passivation on the Frictional Behaviors of Hydrogenated Amorphous Carbon Films

Contact Info

Product

Resources

About