1. Influence of laser colour marking on the corrosion properties of low alloyed TiTadeja Kosec, Andraž Legat, Janez Kovač, Damjan Klobčar, 2019, original scientific article Abstract: In the field of surface treatment, laser colour marking can be used to produce coloured marks on the surfaces of metals. Laser colour markings can be applied to various materials, but on titanium alloys a wide spectra of vivid colours can be achieved. This study presents an analysis of the corrosion properties of laser treated surfaces that were exposed to aggressive environments. Different samples were prepared with laser light of various power intensities and processing speeds. The samples were prepared on low alloyed Ti. Electrochemical, spectroscopic and microstructural analyses were conducted in order to study the properties of the laser treated surfaces. Corrosion testing showed different effects of laser power and production speed on the properties of the laser treated surfaces. It was shown that a high intensity and slow processing rate affect the surfaces by forming oxides that are relatively stable in a corrosive environment of 0.1 M NaCl. Spectroscopic investigations including scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses showed the differences in chemical structure of the surface layer formed after laser treatment. Similarly, microstructural investigations showed different effects on the surface and sub-surface layer of the laser treated samples. Keywords: Ti alloy, laser treatment, XPS, corrosion Published in DiRROS: 25.10.2023; Views: 340; Downloads: 131 Full text (3,16 MB) This document has many files! More... |
2. |
3. ToF-SIMS depth profiling of metal, metal oxide, and alloy multilayers in atmospheres of ▫$H_2$▫, ▫$C_2H_2$▫, CO, and ▫$O_2$▫Jernej Ekar, Peter Panjan, Sandra Drev, Janez Kovač, 2022, original scientific article Keywords: Ions, Layers, Mass spectrometry, Metals, Oxides, SIMS depth profiling H2 C2H2 CO and O2 atmosphere gas flooding cluster secondary ions matrix effect Published in DiRROS: 18.10.2023; Views: 283; Downloads: 133 Full text (8,02 MB) This document has many files! More... |
4. Depassivation and repassivation of stainless steels by stepwise pH changeEmir Mujanović, Bojan Zajec, Andraž Legat, Tadeja Kosec, Janez Kovač, Gregor Mori, Stefan Hönig, Gerald Zehethofer, 2020, original scientific article Abstract: Immersion tests with different stainless steels have been performed, while the pH was stepwise decreased and then increased again. During 8.5-day exposure, the depassivation and repassivation pH values as a function of pitting resistance equivalent number were determined. There is always a gap between both pH values (depassivation and repassivation), indicating that for every steel, there are conditions where an existing passive layer can be maintained but cannot be rebuilt after depassivation. In such environments, the passive layer is thicker, consisting mainly of molybdenum and iron rich oxides, while chromium is dissolved. Usually, depending on conditions, the passive layer is more chromium-rich, especially the inner layer. This is relevant, for example, for acidizing jobs in oil and gas industry, proving that repassivation after acidizing will happen promptly, when the pH is increased again. Keywords: stress corrosion cracking, surface finish impact, tapered tensile specimen, autoclave, accelerated testing, light water nuclear reactor, critical threshold stress Published in DiRROS: 30.08.2023; Views: 270; Downloads: 137 Full text (4,01 MB) This document has many files! More... |
5. The influence of catechols on the magnetization of iron oxide nanoparticlesStanislav Čampelj, Matic Pobrežnik, Tomas Landovsky, Janez Kovač, Layla Martin-Samos, Věra Hamplová, Darja Lisjak, 2023, original scientific article Keywords: magnetni nanodelci, kateholi, adsorpcija, magnetne lastnosti, XPS, DFT Published in DiRROS: 12.06.2023; Views: 315; Downloads: 170 Full text (7,50 MB) This document has many files! More... |
6. Effect of laser texturing pattern on Ti6Al4Vtribocorrosion in a physiological solutionMarjetka Conradi, Tadeja Kosec, Bojan Podgornik, Aleksandra Kocijan, Janez Kovač, Damjan Klobčar, 2022, original scientific article Abstract: Laser texturing is a process that alters a material’s surface properties by modifying its morphology, which can improve properties like adherence, wettability, thermal and electrical conductivity and friction. Here, the effect of laser texturing was studied on an alpha-beta titanium alloy (Ti6Al4V) biomedical material. Two types of patterned surfaces, cross-hatch with varying scan-line separations, Dx = 100, 180 and 280 μm and dimples of 200 μm size, were prepared on the surface of alpha-beta titanium alloy by laser technology. Prepared samples were characterised for their surface properties, such as corrosion, wear-induced corrosion, friction and wettability. Electrochemical and tribocorrosion properties in a physiological solution were studied on the samples with different texture densities of cross-hatch pattern and dimples and compared to the as-received alpha-beta titanium alloy surface. Corrosion rate decreased for laser-textured samples, especially for cross-hatch texture (down to 1 μm/year for Dx = 180 μm) when compared to the as-received alpha-beta titanium alloy surface due to the changed laser-induced surface film and wetting properties. Friction coefficient slightly decreased for all laser-textured surfaces, most noticeably for cross-hatch patterns, from 0.38 (as-received) down to 0.34 (Dx = 180 and 280 μm). The main contribution to total wear in physiological solution increased due to the mechanical wear, which is governed by the removal of the surface oxide layer induced by laser texturing. Keywords: TiAIV, laser texturing, tribocorrosion, open access Published in DiRROS: 17.05.2023; Views: 269; Downloads: 109 Full text (2,19 MB) This document has many files! More... |
7. Synergistic enhancement of photocatalytic CO [sub] 2 reduction by plasmonic Au nanoparticles on TiO [sub] 2 decorated N-graphene heterostructure catalyst for high selectivity methane productionKamal Khaja Mohaideen, Rekha Narayan, Narendraraj Chandran, Stefan Popovic, Mohammed Azeezulla Nazrulla, Janez Kovač, Nika Vrtovec, Marjan Bele, Nejc Hodnik, Marjeta Maček, Blaž Likozar, 2022, original scientific article Published in DiRROS: 09.03.2022; Views: 903; Downloads: 543 Full text (6,73 MB) This document has many files! More... |
8. Increasing the oxygen-evolution reaction performance of nanotubular titanium oxynitride-supported Ir nanoparticles by a strong metal - support InteractionMarjan Bele, Primož Jovanovič, Živa Marinko, Sandra Drev, Vid Simon Šelih, Janez Kovač, Miran Gaberšček, Gorazd Koderman Podboršek, Goran Dražić, Nejc Hodnik, Anton Kokalj, Luka Suhadolnik, 2020, original scientific article Published in DiRROS: 26.11.2020; Views: 1884; Downloads: 1114 Full text (6,25 MB) This document has many files! More... |
9. Structural and CO [sub] 2 capture properties of ethylenediamine-modified HKUST-1 metal-organic frameworkNika Vrtovec, Matjaž Mazaj, Gianpiero Buscarino, Angela Terracina, Simonpietro Agnello, Iztok Arčon, Janez Kovač, Nataša Zabukovec Logar, 2020, original scientific article Keywords: functionalization, modification, adsorption, extended X-ray absorption fine structure, materials Published in DiRROS: 25.11.2020; Views: 2257; Downloads: 934 Full text (3,94 MB) This document has many files! More... |
10. Mechanisms of copper-based catalyst deactivation during CO [sub] 2 reduction to methanolAnže Prašnikar, Andraž Pavlišič, Francisco Ruiz-Zepeda, Janez Kovač, Blaž Likozar, 2019, original scientific article Keywords: catalyst deactivation, methanol synthesis, deactivation mechanism, modelling Published in DiRROS: 24.11.2020; Views: 1270; Downloads: 952 Full text (4,46 MB) This document has many files! More... |