The larger roughness, opposite to the friction-on-roughness dependence in the macroscale. For the microcrater pattern shown in Figures 1a and ten, the impact seems to become a lot more surprising than for the microgroove patterns because of a drastically thinner layer of nanoparticles formed in the course of fs-laser processing. These findings are of excellent interest in fundamental nanotribological studies of carbon-based films [52], and they clearly demonstrate the efficiency of fs-laser ablation processing of DLN films to manage the nano-/microfriction behavior from the hard coatings with potential applications in micro/nanoelectromechanical systems and small-scale devices operating in humid air environments. four. Conclusions Tribological properties from the DLN coatings deposited on silicon and steel substrates have been studied under different circumstances influenced by environments (humid air, water and oil lubrication, elevated temperatures) and laser surface texturing. Comparative tribological tests of difficult DLN films in humid air and beneath water sliding against various counterbodies (steel, silicon-nitride) have demonstrated the low-friction and low-wear functionality on the films below water lubrication, in the absence of chemical interaction of water with all the counterbody surface. A robust influence on the aqueous atmosphere on the wear behavior was revealed for the DLN/Si3 N4 tribopair: the wear prices in the film and Si3 N4 ball in water, W = 7.five 10-9 mm3 /(Nm) and W = 2.6 10-9 mm3 /(Nm), were discovered to be considerably reduced than the corresponding values W = 6.8 10-7 mm3 /(Nm) and W = 3.eight 10-8 mm3 /(Nm) in humid air, in spite of greater friction in water-lubricated sliding. Particular interest within this work has been paid for the high-precision surface texturing of DLN films with femtosecond-laser pulses and fabrication of microcrater-based structures of hexagonal geometry, followed by tribological testing from the Disperse Red 1 Autophagy laser-textured DLN samples under oil lubrication at diverse temperatures, from 23 to one hundred C. The influence of laser surface texturing is located in the Lesogaberan site improved friction overall performance at each the room temperature (in comparison to the original films) and elevated temperatures, when the oil viscosity changed from = 945 mm2 /s at 23 C to = 20.four mm2 /s at 100 C (mineral oil MS20). The friction coefficient was reduced from v = 0.1 for the original film to v = 0.Coatings 2021, 11,14 offor the laser-textured surface at area temperature, after which to v = 0.068 at one hundred C. The obtained final results proof that the friction reduction at elevated temperatures is controlled by the total impact of higher stresses at the crater edges (“artificial” roughness), lubricant film stress lift, and wear in the counterbody, characteristic in the mixed lubrication regime of sliding. Along with the macroscale friction research with the laser-textured films, it truly is shown that the nano-/microfriction behavior of the microcrater-based surface structure is characterized by considerably lower friction forces than the original surface as a consequence of robust influence on the capillary forces on friction forces in humid air environment. The findings of this perform proof about fantastic tribological properties of the DLN coatings in a variety of environments, which is often additional improved by high-precision surface texturing with femtosecond-laser pulses.Author Contributions: S.M.P.: writing–original draft preparation, writing–reviewing and editing, project administration; E.V.Z.: investigation; O.
