Tue. Dec 3rd, 2024

Ce of DLN films in ambient air has been attributed to interfacial sliding among the DLN film and graphitizedCoatings 2021, 11, 1203. https://doi.org/10.3390/coatingshttps://www.mdpi.com/journal/coatingsCoatings 2021, 11,two oftribofilm formed around the ball counterface [11,12], confirmed also by later tribological studies of DLN films [157]. Of great interest will be the friction and wear properties of DLN films below the situations altering the graphitized tribofilm formation, e.g., below liquid (water, oil) lubrication, at elevated temperatures, which would extend the functional capabilities of the coatings. Owing to low internal stresses [7], it is achievable to produce DLN films of relatively huge thickness (up to ten ), retaining the hardness and elastic properties [7,19,20], which allows a laser surface Chetomin In stock texturing (LST) approach to become applied for further improvements of friction and wear properties of DLN coatings [16,20]. It was the modest thickness (of 1 ) that strongly limited the laser surface texturing of DLC films in early experiments of lubricated sliding, when the DLC film deposition onto laser-textured steel or silicon substrates had been proposed as an option texturing technique for DLC-coated surfaces [214]. This approach, option to direct laser surface texturing of DLC films, had disadvantages dealing with the have to have of mechanical polishing of laser-textured substrates before deposition of thin DLC films (to remove protruding rims around dimples) [21,23], and weaker adhesion of DLC coatings at the dimple edges top to the film delamination in the course of sliding [22]. Lately, femtosecond (fs) laser processing of DLN films has been demonstrated as an effective approach to control the friction properties at the nano, micro, and 5-Propargylamino-ddUTP Chemical macroscale [16,20,257] and to improve tribological properties of laser-textured DLN films in lubricated sliding [16,26]. The majority of the significant findings for fs-laser-textured DLN films are related to regular patterns of parallel microgrooves and arrays of microcraters fabricated below particular irradiation conditions limited to a provided structure size of ten (groove width, crater diameter), structure depth of some microns and period of 20 . Further optimization of laser surface texturing of DLN films is needed, aiming at fabrication of microstructures of lower size and higher aspect ratio, and improve in the throughput of microprocessing with high spatial precision. In this paper we concentrate on the effects of environments and laser surface texturing on tribological performance of DLN coatings. Firstly, we present the results of comparative tribological testing of DLN films in humid air and water under linear reciprocating sliding against steel and silicon-nitride balls, and demonstrate the friction pair-dependent wear character of the rubbing supplies under water lubrication. Secondly, we present experimental information of high-precision surface texturing of DLN films with fs-laser pulses and fabrication of microcrater-based structures of hexagonal geometry, followed by tribological testing with the laser-textured DLN samples below oil lubrication at room temperature and one hundred C. Additionally, we demonstrate how the nano-/microfriction behavior is changed in the laser-structured region consisting of microcraters employing friction force microscopy in humid air. 2. Materials and Methods 2.1. DLN Film Properties DLN films had been grown on silicon and steel substrates working with a plasma-assisted chemical vapor deposition (PAC.