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Articles you may be interested inStudy of the fatigue wear behaviors of a tungsten carbide diamond-like carbon coating on 316L stainless steel J. Vac. Sci. Technol. A 30, 051506 (2012); 10.1116/1.4737619 Superhard behaviour, low residual stress, and unique structure in diamond-like carbon films by simple bilayer approach J. Appl. Phys. 112, 023518 (2012); 10.1063/1.4739287 Temperature dependent properties of silicon containing diamondlike carbon films prepared by plasma source ion implantation J. Appl. Phys. 107, 083307 (2010); 10.1063/1.3394002 Structure and corrosion behavior of platinum/ruthenium/nitrogen doped diamondlike carbon thin filmsTungsten-containing diamondlike carbon ͑W-DLC͒ coatings have been deposited on FKM ͑fluorocarbon͒, ACM ͑acrylate͒, and HNBR ͑hydrogenated nitrile butadiene͒ rubbers via unbalanced magnetron reactive sputtering from a WC target in C 2 H 2 / Ar plasma. The surface morphology and fracture cross sections of coated rubbers have been scrutinized by high resolution scanning electron microscopy ͑SEM͒. The random crack networks formed due to the large difference in the coefficients of thermal expansion break down the W-DLC coatings into segments of a couple of hundred micrometers in size, facilitating good flexibility if the interfacial adhesion between the coating and a rubber substrate is strong enough. The size and density of growth defects in the W-DLC coatings strongly depend on the surface roughness of the rubber sheets. The tribological behavior of uncoated and coated rubbers has been investigated with ball-on-disk tribotest under dry sliding condition against a 6 mm 100Cr6 ball. Uncoated rubbers exhibited a very high coefficient of friction ͑Ͼ0.9͒. W-DLC coated FKM did not considerably reduce the friction because the coating was damaged due to poor adhesion. W-DLC coated HNBR and ACM exhibited excellent tribological performance, and very low coefficients of friction ͑Ͻ0.24͒ were achieved even at high normal load of 5 N. After tribotests, the W-DLC coatings on HNBR and ACM were intact and no serious damage was observed on the wear tracks.

The paper employs a rough-surface numerical elastic contact method designed to analyze Hertzian elastic contact effects of surface coatings. In particular the paper explores the differences in the surface contact mechanics and the resulting sub-surface stresses experienced over a range of differing coating material-properties, thickness, and machined roughness levels in a quantitative manner. The effect of a range of surface roughness properties and in particular root mean square roughness (σ) and correlation length β*, on the magnitude and depth of maximum shear stresses in the layer under individual asperities is investigated. This is done for a hard and stiff, and also for a soft and compliant coating, and for two coating thicknesses in each case. The results suggest that the magnitude of the local shear stress increases with increasing ratio σ/β* approximately linearly. The depth of the maximum local shear stress is found to correlate best with β*, however a further clear trend is observed between this depth and the number of profile peaks. The depth also shows a relation to the ratio σ/β* but the correlation in this case is weaker with significant deviations. Neither the magnitude nor the depth of shear stresses shows any significant trend in relation to the roughness (σ) alone. The tensile stresses at the interface, and the subsequent potential for delamination, are also investigated and found to be significant. Approximate correlation between the magnitude of interface tensile stress and root mean square roughness is achieved, but no clear trend in relation to correlation length is evident.

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.

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