The Use of Triboemission Imaging and Charge Measurements to Study DLC Coating Failure

Ciniero, Alessandra; Rouzic, Julian Le; Reddyhoff, Tom

doi:10.3390/coatings7080129

Cited by 7 publications

(6 citation statements)

References 38 publications

(43 reference statements)

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“…A diamond-like coating (DLC) was obtained by sputtering a graphite target in a glow discharge plasma, resulting in an amorphous coating structure consisting of carbon atoms with both diamondand graphite-like bonds [44,45]. This coating is traditionally characterized by a low friction coefficient and has noticeably higher microhardness values in comparison to tool ceramics.…”

Section: Deposition Of Vacuum-plasma Coatings On Ceramics and Coatingmentioning

confidence: 99%

The Role of Thin-Film Vacuum-Plasma Coatings and Their Influence on the Efficiency of Ceramic Cutting Inserts

et al. 2018

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The main problem with ceramics used in cutting tools is related to the unpredictable failures caused by the brittle fracturing of ceramic inserts, which is critical for the intermittent milling of cyclic loading. A 125-mm-diameter eight-toothed end mill, with a mechanical fastening of ceramic inserts, was used as a cutting tool for milling hardened steel (102Cr6). For the experiments, square inserts of the Al2O3 + SiC ceramic were used and compared with the samples made of Al2O3 + TiC to confirm the obtained results. The samples were coated with diamond-like coating (DLC), TiZrN, and TiCrAlN coatings, and their bending strength and adhesion were investigated. Investigations into the friction coefficient of the samples and operational tests were also carried out. The effect of smoothing the microroughness and surface defects in comparison with uncoated inserts, which are characteristic of the abrasive processing of ceramics, was investigated and analyzed. The process developed by the authors of the coating process allows for the cleaning and activation of the surface of ceramic inserts using high-energy gas atoms. The impact of these particles on the cutting edge of the insert ensures its sharpening and reduces the radius of curvature of its cutting edges.

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Section: Deposition Of Vacuum-plasma Coatings On Ceramics and Coatingmentioning

confidence: 99%

The Role of Thin-Film Vacuum-Plasma Coatings and Their Influence on the Efficiency of Ceramic Cutting Inserts

et al. 2018

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“…Despite being one of the most known and long studied physical phenomena, triboelectrification is still poorly understood 5,6 and the mechanism behind it is still under debate especially for insulatorinsulator contact. Several theories have suggested that the electrification is due to the transfer of electrons [7][8][9][10][11][12][13] , ions [14][15][16][17] or microscopic fragments of material [18][19][20][21] that act as charge carriers, however, no consensus has been yet achieved. This lack of fundamental understanding of triboelectrification hinders the development and the improvement of effective TENGs.…”

Section: Introductionmentioning

confidence: 99%

Ab Initio Study of Polytetrafluoroethylene Defluorination for Tribocharging Applications

Fatti

Righi

Dini

et al. 2020

ACS Appl. Polym. Mater.

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Polytetrafluoroetyhlene (PTFE) is one of the most efficient polymers for green energy-harvesting devices like triboelectric nanogenerators because of its high capability of acquiring and retaining negative charge. Despite its extensive use, the relation between PTFE triboelectric behavior and its electronic properties has never been analyzed. To shed light on this important feature we have studied the electronic properties of PTFE low-index surfaces in the high pressure phase by means of density functional theory. We start by showing that adding either a positive or a negative charge on pristine surfaces is energetically unfavorable. We then demonstrate the role played by surface defects. When a surface fluorine vacancy is introduced the analysis of the band structure reveals that the defect generates a trap state that enables the surface to acquire and retain negative charge.

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“…However, the tribological properties of DLC films depend on not only the intrinsic parameters, but also many extrinsic factors, such as sliding velocity, normal load, environment atmosphere, and properties of friction interfaces [12][13][14][15]. In particular, the effect of sliding velocity on the friction characteristics of DLC films has been extensively studied, giving rise to a large amount of diverging findings [15][16][17]. For instance, it is noted that the friction coefficient of the DLC films increased from 0.07 to 0.22 with increasing of sliding velocity in air, and the reason is due to the entrapment of more debris particles at the sliding interface [18].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2018

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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.

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The Use of Triboemission Imaging and Charge Measurements to Study DLC Coating Failure

Cited by 7 publications

References 38 publications

The Role of Thin-Film Vacuum-Plasma Coatings and Their Influence on the Efficiency of Ceramic Cutting Inserts

The Role of Thin-Film Vacuum-Plasma Coatings and Their Influence on the Efficiency of Ceramic Cutting Inserts

Ab Initio Study of Polytetrafluoroethylene Defluorination for Tribocharging Applications

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

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