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Funkcionalizacija površin z lasersko povzročenimi površinskimi strukturami
Velej, Tilen (Author), Gregorčič, Peter (Mentor) More about this mentor... This link opens in a new window

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Abstract
Pri obsevanju z linearno polarizirano lasersko svetlobo in nastankom periodičnih površinskih struktur (LIPSS) na kovinah ali polprevodnikih lahko funkcionaliziramo površino. V nalogi smo na laserskem sistemu, sestavljenem iz polarizatorja, skenirne glave z F-theta lečo in pozicionirne mizice, uporabili pikosekundni trdninski laser z valovno dolžino 1064 nm in nanosekundni vlakenski laser z valovno dolžino 1060 nm. Raziskovali smo nastanek LIPSS in njegov vpliv na obarvanje ter omočljivost površin. Najprej smo dokazali, da LIPSS dobimo pri obeh laserskih virih, pri tem pa imata ključno vlogo polarizacija in valovna dolžina izsevane svetlobe, saj je bila orientiranost LIPSS vedno pravokotna na polarizacijo, perioda LIPSS pa približno 92 % valovne dolžine izsevane svetlobe. Raziskali smo še vpliv sledečih parametrov: frekvence in oblike bliskov, hitrosti označevanja, razmika med skenirnimi linijami, povprečne moči bliskov, oddaljenosti obdelovanca od gorišča in atmosfere. Na poliranem vzorcu nerjavnega jekla AISI 316 smo izmerili časovno odvisnost omočljivosti po laserskem označevanju v zraku, argonu in dušiku. Rezultati kažejo, da pri obdelavi v inertni atmosferi in s površinskim nastankom LIPSS, zlasti pa mikrokanalov (pri višjih fluencah), najprej zvečamo omočljivost površin, ki pa se z izpostavljenostjo zraku spremenijo v močno hidrofobne. Na vzorcu, ki je prvotno kazal hidrofilne lastnosti, smo ustvarili superhidrofobno površino s kontaktnim kotom nad 150°.

Language:Slovenian
Keywords:laserski inženiring površin vlakenski laser lasersko teksturiranje omočljivost funkcionalizacija površin periodične površinske strukture
Work type:Final paper (mb12)
Tipology:2.11 - Undergraduate Thesis
Organization:FS - Faculty of Mechanical Engineering
Year:2018
Publisher:[T. Velej]
UDC:621.9.048.7(043.2)
COBISS.SI-ID:16287259 Link is opened in a new window
Views:246
Downloads:143
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Secondary language

Language:English
Title:Surface functionalization by laser-induced periodic surface structures
Abstract:
By producing laser-induced periodic surface structures (LIPSS) upon irradiation with linearly polarized pulses on metals or semiconductors we can achieve functionalized surfaces. For sample texturing we used a laser system consisting of a polarizer, a scanning head with F-theta lens and a positioning system. We used a picosecond solid-state laser with wavelength of 1064 nm and a nanosecond fiber laser with wavelength of 1060 nm. In this thesis we investigated LIPSS formation and its influence on surface color and wettability. We confirmed that LIPSS can be achieved using both laser sources. Polarization and wavelength of irradiated light played a key role in LIPSS formation, since LIPSS orientations were always perpendicular to the laser polarization and LIPSS periods being of approximately 92 % value of the laser wavelength. By experimentation we also determined the influence of the following parameters: pulse frequency, pulse waveform, marking speed, line separation distance, average pulse power, sample displacement out of the focal position and atmosphere. After laser processing in air, argon and nitrogen atmospheres we investigated a time dependency of surface wettability, textured on polished sample of stainless steel AISI 316. Results showed that formation of LIPSS and especially microgrooves (when being irradiated with high fluence light) in an inert atmosphere firstly increased surface wettability, but following air exposure surfaces became strongly hydrophobic. We managed to modificate a sample with originally hydrophilic behavior into a superhydrophobic surface with contact angle above 150°.

Keywords:laser surface engineering fiber laser laser texturing wettability surface functionalization periodic surface structures

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