Flexible diamond-like carbon films on rubber: On the origin of self-acting segmentation and film flexibility

Abstract

2012). Flexible diamond-like carbon films on rubber: On the origin of self-acting segmentation and film flexibility. Acta Materialia, 60(15), 5526-5535. https://doi.org/10.1016Materialia, 60(15), 5526-5535. https://doi.org/10. /j.actamat.2012 Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. AbstractThis paper reports an experimental approach to deposit flexible diamond-like carbon (DLC) films on hydrogenated nitrile butadiene rubber (HNBR) with plasma-assisted chemical vapor deposition and an analytical model to describe the self-segmentation mechanism of the DLC films. By making use of the substantial thermal expansion mismatch between the DLC films and the rubber substrate, a dense network of cracks forms in the DLC films and contributes to flexibility. The size of the microsegments can be controlled by tuning the temperature variation of the substrate during deposition through varying the substrate bias voltage. The formation mechanism of the crack network and its effect on the flexibility of DLC films coated on rubber are presented.

Flexible DLC film coated rubber: friction and the effect of viscoelastic deformation of rubber substrate

“…The ratio of gas flow rates was set at Ar:C 2 H 2 =3:2, and constant process pressure of 3×10 -3 mbar. The detailed PACVD process is referred to our previous work [5]. The DLC films are named as DLCxxx-yyyV, e.g.…”

“…The wax removal and cleaning processes of HNBR substrates (45×45 mm 2 size) have been described in detail elsewhere [5]. Plasma cleaning treatment of rubber substrates and successive plasma assisted CVD (PACVD) deposition of DLC films were carried out in a Teer UDP400/4 closed-field unbalanced magnetron sputtering system with all the magnetrons powered off.…”

“…Obviously, there are technical problems with this approach: the size of film segments is rather limited to submillimeter and especially the open gap that produced a large amount of debris and led to a high friction and severe wear of coated rubber [3]. Another approach was recently developed for depositing micro-segmented DLC films of superior flexibility on rubber [5]. The novelty is that the segmentation process of DLC films is self-adjusting throughout the deposition and the size of film segments separated by crack network can be well controlled at much smaller length scales.…”

Influence of load on the dry frictional performance of alkyl acrylate copolymer elastomers coated with diamond-like carbon films

“…In dry conditions, films with better flexibility tend to show lower CoF than coatings with worse flexibility. 9,19,21 The presence of cracks in a patched structure facilitates the flexibility of the DLC coatings, leading to lower CoFs. Such results reproduce what has been observed earlier in a conventional tribometer.…”

“…The microstructure of the films depends on the temperature variations of the films, since rubber substrates shrink or expand during film growth, causing the DLC coating to break during film growth. 19,21 For this study, two coatings with varied microstructures 15,19,20 were selected (see Figure 2); on the one hand, a continuous DLC film (see Fig. 2, left), which was deposited at constant temperature during deposition; on the other hand, a patched DLC film (see Figure 2, right), which was deposited with a large and negative temperature variation during film growth.…”