Gure 6b shows the reduced COF values for the laser-textured surface, v= 0.085 at R = 4.five mm and v = 0.081 (averaged over two friction laser-textured surface, av = 0.085 at R = four.five mm and av = 0.081 (averaged over two friction tests) at R = 33mm, than the friction coefficient v= 0.1 for the original film. The WLI tests) at R = mm, than the friction coefficient av = 0.1 for the original film. The WLI pictures of the put on tracks and surface profiles across the tracks, measured soon after removal of photos on the put on tracks and surface profiles across the tracks, measured right after removal the the filmfilm with n-heptane,shown in Figure 7, which give information about concerning the of oil oil with n-heptane, are are shown in Figure 7, which give information the wearwear character on the DLN film surface throughout lubricated sliding. The depth on the put on tracks around the original film (Figure 7a,d) and laser-textured surface at R = four.5 mm (Figure 7b,d) is extremely small–dtr = 19 nm and dtr = 28 nm, respectively. The difference of ten nm inside the track depth could possibly be as a consequence of (i) a thin layer of ablated material around the laser-texturedCoatings 2021, 11,9 ofcharacter on the DLN film surface through lubricated sliding. The depth of the put on tracks around the original film (Figure 7a,d) and laser-textured surface at R = 4.5 mm (Figure 7b,d) is quite small–dtr = 19 nm and dtr = 28 nm, respectively. The difference of 10 nm inside the track depth might be on account of (i) a thin layer of ablated material on the laser-textured surface very easily removed in the track location for the duration of sliding [26], or (ii) slightly improved put on as a result of protruding edges of microcraters. The width of both the tracks is about wtr = 48 , smaller sized than the estimated value from the contact region diameter of 2Rcont 61 . The put on with the ball surface is also extremely tiny, that is pronounced within the appearance of individual scratches inside the wear scars surface much less Deguelin supplier discernible for the ball sliding on the original surface, as shown in Figure 8a,b. Under the observed low-wear Glycol chitosan Autophagy prices of your film and ball counterparts the friction reduction around the laser-textured film (shown in Figure 6b) is as a consequence of lubricant film pressure lift inside the mixed lubrication regime of sliding, constant with our preceding experiments using the microcrater patterns of greater region density (20 and 40 ) and lubrication with synthetic motor oil of higher viscosity [26]. Compared together with the previous benefits [26], the influence in the reasonably tiny (10 ) dimpled location density around the lubricated friction overall performance with the fs-laser-textured DLN films appears significant, Coatings 2021, 11, x FOR PEER Evaluation ten of 16 implying that the texture optimization is needed for any offered tribosystem used and for every certain application of laser-patterned DLC films.Figure 7. WLI images on the put on tracks Figure 7. WLI photos with the wear tracks formed on (a) the original film at R = 7 mm and (b) laseroriginal film at R = 7 mm and (b) lasertextured surface at R = four.5 mm just after lubricated sliding at T = 23 C, and (c) following all the successive textured surface at R = four.5 mm soon after lubricated sliding at T = 23 , and (c) right after all the successive lubricated sliding tests on the laser-textured film R = three mm and different temperatures; (d) surface lubricated sliding tests on the laser-textured film atat R = 3 mm and distinct temperatures; (d) surface profiles across the tracks measured along the marked lines inside the WLI photos. profiles across the tracks measured along the marked line.
