Rve (in Figure 9a) is controlled by the balance amongst higher stresses generated around microcraters in the make contact with location, acting as “artificial” roughness, and lubricant film stress lift within the non-conformal sliding speak to [41,44]. An extra crucial parameter is definitely an escalating put on on the ball, which results in a gradual increase inside the speak to location, transition from the boundary to the mixed lubrication regime, and towards the friction reduction [42]. The information in the wear character from the film and ball surfaces throughout lubricated sliding at elevated temperatures are shown in Figure 7c,d and Figure 8c,d. The put on track at R = 3 mm, shown in Figure 7c, was formed right after all the successive lubricated sliding tests in the laser-textured film at unique temperatures, providing information about the total effect of your six sliding tests on the wear on the film surface. This total effect is pronounced in the increased width wtr = 83 and depth dtr = 60 nm from the wear track at R = 3 mm in comparison with the put on track at R = four.five mm formed for the duration of sliding at T = 23 C. The photos of the wear scars indicate the increased wear on the ball immediately after each and every of two lubrication tests at elevated temperatures. It really is the lubricated sliding at elevated temperatures which results in the elevated wear of the ball, as a result of a strongly reduced thickness of your lubricant film. So the friction reduction at T = 100 C, shown in Figure 9a,b, is controlled by the total impact of higher stresses at the crater edges (“artificial” roughness), lubricant film pressure lift, and put on from the ball, characteristic on the mixed lubrication regime of sliding. It’s also critical to note that the adhesion of your laser-texture film to steel substrate is sufficiently high to supply the low-friction performance of the film below oil lubrication at T = 100 C, common from the engine’s KN-62 Autophagy operation circumstances in harsh atmosphere. To conclude, the laser-textured DLN coatings on steel, using the surface micropattern characterized by high-symmetry hexagonal geometry and smaller (10 ) dimpled area density, have demonstrated outstanding tribological properties below oil lubrication and elevated temperatures. The lubricated friction efficiency of the laser-textured films has been improved at space temperature, in comparison with the original non-patterned surface, and elevated temperatures. 3.3. Nano/Microfriction Behavior of Laser-Textured DLN Films The nano-/microfriction behavior of laser-textured DLN films was studied working with Pitstop 2 Apoptosis contact-mode AFM procedures, which includes lateral force microscopy (LFM) and force istance curve measurements. The LFM method allows the surface relief and lateral (friction) force images to be measured simultaneously throughout tip scanning [45,46], and for relatively large scanning regions (from 20 20 to 160 160 ) it enables the friction forces to be determined in laser-patterned and original surface places of DLC films. Measurements of the force istance curves [47,48] are used to decide the capillary forces in between the AFM tip and film surface on the laser-patterned and non-patterned regions. These contact-mode AFM methods had been applied to study the nano and microscale friction properties of laser-produced microgrooves on DLN films, described in detail in refs. [16,25]. In this paper, the AFM approaches are applied to examine the surface properties in the laserstructured surface area consisting of microcraters, especially, the laser-structured film shown in Figure 1a. The surface relief.
