Browsing by Author "Orazi, L."
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Item Open Access Laser-patterning stainless steel with nonlinear laser lithography for enhanced tribological properties(IEEE, 2015) Gnilitskyi, I.; Pavlov, Ihor; Rotundo, F.; Orazi, L.; İlday, Serim; Martini, C.; İlday, F. ÖmerThe production of nanostructures on different materials attracts much attention in different fields of manufacturing as a result of increased availability, affordability and technical capability of laser-based methods [1,2]. However, some shortcomings such as relatively low speed of processing, problems with material control, and lack of uniformity and/or repeatability over large areas continue to limit their practical adaptation.Item Open Access Nano patterning of AISI 316L stainless steel with nonlinear laser lithography: sliding under dry and oil-lubricated conditions(Elsevier Ltd, 2016) Gnilitskyi, I.; Rotundo, F.; Martini, C.; Pavlov, I.; Ilday, S.; Vovk, E.; Ilday, F. Ö.; Orazi, L.Femtosecond laser-based Nonlinear Laser Lithography (NLL) was applied to AISI 316L stainless steel, which requires surface modification to achieve satisfactory tribological behaviour. NLL advances over the well-known Laser Induced Periodic Surface Structures (LIPSS) in terms of uniformity and long-range order of high speeds, over large areas. A galvanometric scanner head was used for an high production rate. Dry and lubricated sliding tests, considering different orientations of the nanotexture showed that COF values after NLL treatment are significantly lower. In lubricated tests, COF values of NLL-treated surfaces are nearly half the values of untreated surfaces, whereas the difference further increases when measured in dry conditions, where the orientation of the surface texturing influences the results.Item Open Access Nonlinear laser lithography for enhanced tribological properties(IEEE, 2015-05) Gnilitskyi, I.; Pavlov, Ihor; Rotundo, F.; Orazi, L.; Martini, C.; İlday, Fatih ÖmerThis paper investigates a new field for application of femtosecond laser-induced periodic surface structures (LIPSS). We designed an innovative solution to reduce coefficient of friction of mechanical parts by using the nonlinear laser lithography technique (NLL). © 2015 OSA.Item Open Access Nonlinear laser lithography to control surface properties of stainless steel(Elsevier BV, 2015) Orazi, L.; Gnilitskyi, I.; Pavlov, I.; Serro, A. P.; Ilday, S.; Ilday, F. O.In the present work a novel method to improve the surface properties of stainless steel is presented and discussed. The method, based on the use of a high repetition rate femtosecond Yb fibre laser, permits generation of highly reproducible, robust, uniform and periodic nanoscale structures over a large surface area. The technique is characterized by high productivity, which, in its most simple form, does not require special environmental conditioning. Surface morphology is scrutinized through SEM and AFM analyses and wettability behaviour is investigated by means of the sessile drop method using distilled-deionized water. It is shown that optimization of process parameters promotes anisotropic wetting behaviour of the material surface.