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, 11,2 oftribofilm formed around the ball counterface [11,12], confirmed also by later tribological studies of DLN films [157]. Of terrific interest would be the friction and wear properties of DLN films below the situations changing the graphitized tribofilm formation, e.g., below liquid (water, oil) lubrication, at elevated temperatures, which would extend the functional capabilities on the coatings. Owing to low internal stresses [7], it truly is feasible to generate DLN films of relatively large thickness (as much as ten ), retaining the hardness and elastic properties [7,19,20], which makes it possible for a laser Phleomycin supplier surface texturing (LST) method to become applied for further improvements of friction and put on properties of DLN coatings [16,20]. It was the little thickness (of 1 ) that strongly restricted 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 alternative texturing method for DLC-coated surfaces [214]. This method, option to direct laser surface texturing of DLC films, had disadvantages dealing with the will need of mechanical polishing of laser-textured substrates just before deposition of thin DLC films (to get rid of protruding rims about dimples) [21,23], and weaker adhesion of DLC coatings in the dimple edges major to the film delamination in the course of sliding [22]. Not too long ago, femtosecond (fs) laser processing of DLN films has been demonstrated as an efficient strategy to manage the friction properties at the nano, micro, and macroscale [16,20,257] and to enhance tribological properties of laser-textured DLN films in lubricated sliding [16,26]. Many of the critical findings for fs-laser-textured DLN films are associated to regular patterns of parallel microgrooves and arrays of microcraters fabricated under specific irradiation circumstances limited to a offered structure size of 10 (groove width, crater diameter), structure depth of a number of microns and period of 20 . Further optimization of laser surface texturing of DLN films is required, aiming at fabrication of microstructures of reduced size and larger aspect ratio, and improve within the throughput of microprocessing with higher spatial precision. In this paper we concentrate on the effects of environments and laser surface texturing on tribological functionality 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 put on character on the rubbing supplies beneath 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 in the laser-textured DLN samples beneath oil lubrication at area temperature and one hundred C. Furthermore, we demonstrate how the nano-/microfriction Diflucortolone valerate Epigenetics behavior is changed in the laser-structured area consisting of microcraters applying friction force microscopy in humid air. 2. Materials and Procedures 2.1. DLN Film Properties DLN films have been grown on silicon and steel substrates utilizing a plasma-assisted chemical vapor deposition (PAC.
