Časovno spremenljiva omočljivost lasersko teksturiranih jeklenih površin

Modrijan, Marjeta (author), Zupančič, Matevž (mentor), Gregorčič, Peter (comentor)

Površine s specifično omočljivostjo so uporabne na različnih področjih tehnike, v kmetijstvu, živilski industriji in medicini. V naravi omočljivost ali neomočljivost površin živali in rastline izrabljajo za preživetje. Najbolj poznan je primer superneomočljive površine lotosovega lista, ki se odraža tudi v samočistilnosti, ki preprečuje razrast bakterij in mikroorganizmov. V zaključni nalogi pokažemo, da je superneomočljive kovinske površine mogoče izdelati s kombinacijo laserskega teksturiranja kovinskih površin in njihovega naknadnega nizkotemperaturnega žarjenja v kontaminirani peči. Vzorce iz nerjavnega jekla smo lasersko teksturirali s pomočjo vlakenskega laserja z 28 ns bliski ter valovno dolžino 1060 nm. Zatem smo jih nizkotemperaturno žarili pri 100°C, 200°C, 250°C in 300°C. Pred, med in po žarjenju smo na vzorcih spremljali kot omočenja in kot skotaljenja vodne kapljice. Žarjenje smo ponovili v dveh pečeh pri enakih temperaturah z namenom identifikacije vpliva okoliške atmosfere na prehod iz omočljivega v neomočljivo stanje vzorcev. Ugotovili smo, da do prehoda iz omočljivega v neomočljivo stanje pride zaradi adsorpcije organskih kontaminantov, ki so bili prisotni v peči.

• Language: Slovenian
• Keywords: omočljivost, funkcionalizacija površin, laserski inženiring površin, lasersko teksturiranje, površinska napetost, hidrofilnost, hidrofobnost
• Work type: Final paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FS - Faculty of Mechanical Engineering
• Place of publishing: Ljubljana
• Publisher: [M. Modrijan]
• Year: 2020
• Number of pages: XIV, 31 f.
• PID: 20.500.12556/RUL-119966
• UDC: 544.722.3:532.61:621.9.04(043.2)
• COBISS.SI-ID: 32666115
• Publication date in RUL: 14.09.2020

MODRIJAN, Marjeta, 2020, Časovno spremenljiva omočljivost lasersko teksturiranih jeklenih površin [online]. Bachelor’s thesis. Ljubljana : M. Modrijan. [Accessed 18 March 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=119966

Secondary language

• Language: English
• Title: Time-dependent wettability of laser-textured stainless steel surfaces

Abstract

Surfaces with unique wettability are used in various fields of technology, in agriculture, food industry and medicine. The animals and plants exploit the hydrophilicity or hydrophobicity for their survival. The most famous example of the superhydrophobic surface in nature is the lotus leaf, which has also the self-cleaning ability and in this way, it prevents the growth of bacteria and microorganisms. In this BSc thesis, we demonstrate that superhydrophobic metal surfaces can be produced by a combination of laser texturing and their subsequent low-temperature annealing in a contaminated furnace. Stainless steel samples were laser textured by using a fibre laser radiating 28-ns pulses with a wavelength of 1060 nm. The laser-processed samples were further annealed at 100 °C, 200 °C, 250 °C and 300 °C. Before, during and after annealing, we measured the contact and the roll-off angle of water droplet. The annealing was repeated in two furnaces at the same temperatures in order to identify the influence of the surrounding atmosphere on the hydrophilic-to-hydrophobic transition of the laser-textured samples. We found that this transition occurs due to the adsorption of organic contaminants that were present in the furnace.

• Keywords: wettability, surface functionalities, laser surface engineering, laser texturing, surface tension, hydrophilicity, hydrophobicity