Effects of Fluorine and Silicon Incorporation on Tribological Performance of Diamond-Like Carbon Films

Abstract

Diamond-like carbon (DLC) is a metastable amorphous film that exhibits unique properties. However, a number of limitations exist regarding the use of DLC, for instance, its tribological characteristics. In this article, the fluorine and silicon incorporated diamond-like carbon (F-DLC and Si-DLC) films are studied, taking into account the tribological properties of these films compared with pure DLC. The structures of the films were characterized using Auger electron spectroscopy and Raman spectroscopy. The hardness and elastic modulus were evaluated by nanoindentation hardness testing. The friction behavior was assessed using ball-on-disk friction testing and optical microscopy. The results indicated that the deposited DLC films contained 0.6-2.1 at.% F and 26.7-38.4 at.% Si. A decrease in the hardness and elastic modulus was obtained as F increased in content, which was the opposite of the behavior observed in the Si-DLC films. This was due to the shifting in the G-peak position, which is related to the sp 3 bonding fraction in the film. When measured in ambient air, the addition of Si into the DLC film strongly influenced the friction coefficient, whereas doping with F only slightly influenced the films, as evidenced by their wear scars. In addition, only a 26.7 at.% Si-DLC film showed a very low friction coefficient when measured in dry air. This was attributed to the formation of silicon-rich transfer layer on the ball surfaces. Therefore, the addition of Si with 26.7 at.% content to a DLC film can be considered beneficial for improving tribological performance.

Reduction of Insertion Torque on Orthodontic Mini-screw Implant by means of Reduced Friction

“…The previous study reported that DLC, Si-DLC, and F-DLC films' friction coefficients were 0.18, 0.03, and 0.16, respectively (Jongwannasiri et al, 2019b). The decreasing friction coefficient of the F-DLC film was due to the formation of repulsive forces with F atoms.…”

“…Therefore, three types of DLC coating, namely DLC, Si-DLC, and F-DLC, were deposited on OMIs. A previous study showed that the Si-DLC and F-DLC films deposited at a gas flow rate ratio of 2:1 had shown the lower friction coefficients among all the compositions of DLCs (Jongwannasiri et al, 2019b). Consequently, both of them were selected to study in this experiment.…”

Laser-patterned carbon coatings on flexible and optically transparent plastic substrates for advanced biomedical sensing and implant applications

“…Previous studies have also hinted at the possibility of an improvement in the toughness properties due to the formation of a Si-rich transfer layer on the surface. 66,67 However, the thick SiO x transfer layer obtained at high laser annealing energy densities leads to a film showing high wear. This result indicates that Si-DLC thin films are unsuitable for applications involving high-energy UV irradiation.…”

Effect of Water Adsorption Layers on the Friction Properties of Fluorinated Amorphous Carbon Films in Ambient Air

“…In their calculations, the lowest friction was obtained from the F-terminated DLC model, indicating that a stronger repulsive force and weaker van der Waals interaction occurred at the sliding surface of the F-terminated DLC model. Furthermore, some studies have shown that a-C:H:F films exhibit lower friction coefficients than a-C:H films in ambient air. − …”

“…Researchers have investigated the tribological properties of a-C:H:F and a-C:F films, − and several theories regarding the role of F atoms on friction surfaces have been proposed. Among them, two main reasons for the low friction coefficient of a-C:F films are the passivation of the dangling bonds by F and the repulsive force occurring at the sliding interface owing to the high electronegativity of F .…”