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2. Laser surface modification of CRVN coatings for self-lubricating performanceBojan Podgornik, Barbara Šetina, Miha Čekada, Suman Chatterjee, Dermot Brabazon, 2025, objavljeni znanstveni prispevek na konferenci Ključne besede: CrVN coating, laser modification, hot forming, self-lubrication, wear, friction
Objavljeno v DiRROS: 14.05.2025; Ogledov: 58; Prenosov: 13
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3. Macro to micro stratigraphic and artefactual evidence from an Early Iron Age smithy at the Pungrt hillfort (Central Slovenia)Luka Gruškovnjak, Agni Prijatelj, Petra Vojaković, Jaka Burja, Barbara Šetina, Rok Brajkovič, Borut Toškan, Tjaša Tolar, Helena Grčman, Matija Črešnar, 2025, drugi znanstveni članki Ključne besede: Early Iron Age, geoarchaeology, micromorphology, microrefuse, archaeometallurgy, smithy, floor construction, floor maintenance, lime plaster, hammerscale
Objavljeno v DiRROS: 13.05.2025; Ogledov: 67; Prenosov: 18
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4. From macro to micro approaches in settlement archaeology : a case study of an Early Iron Age smithy at the Pungrt hillfort (Central Slovenia)Luka Gruškovnjak, Agni Prijatelj, Petra Vojaković, Jaka Burja, Barbara Šetina, Rok Brajkovič, Borut Toškan, Tjaša Tolar, Helena Grčman, Matija Črešnar, 2025, izvirni znanstveni članek Ključne besede: Early Iron Age, geoarchaeology, micromorphology, microrefuse, archaeometallurgy, smithy, floor construction, floor maintenance, lime plaster, hammerscale
Objavljeno v DiRROS: 13.05.2025; Ogledov: 76; Prenosov: 33
Celotno besedilo (54,10 MB)
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6. Unveiling the potential of ▫$(CoFeNiMnCr)_3O_4$▫ high-entropy oxide synthesized from CoFeNiMnCr high-entropy alloy for efficient oxygen-evolution reactionBarbara Ljubec Božiček, Jitka Hreščak, Monika Kušter, Janez Kovač, Iztok Naglič, Boštjan Markoli, Barbara Šetina, Martin Šala, Sandra Drev, Živa Marinko, Miran Čeh, Belisa Alcantara Marinho, 2024, izvirni znanstveni članek Povzetek: Electrochemical water-splitting is a promising green technology for the production of hydrogen. One of the bottlenecks, however, is the oxygen evolution half-reaction (OER), which could be overcome with the development of a suitable electrocatalyst. Recently, non-noble metal, high-entropy oxides (HEO) have been investigated as potential OER electrocatalysts, but complex synthesis approaches that usually produce the material in powder form limit their wider utilization. Here, an innovative synthesis strategy of formulating a nanostructured (CoFeNiMnCr)3O4 HEO thin film on a CoFeNiMnCr high entropy alloy (HEA) using facile electrochemical and thermal treatment methods is presented. The CoFeNiMnCr HEA serves as exceptional support to be electrochemically treated in an ethylene glycol electrolyte with ammonium fluoride to form a rough and microporous structure with nanopits. The electrochemically treated CoFeNiMnCr HEA surface is more prone to oxidation during a low-temperature thermal treatment, leading to the growth of a spinel (CoFeNiMnCr)3O4 HEO thin film. The (CoFeNiMnCr)3O4 HEO exhibits a superior overpotential of 341 mV at 10 mA cm−2 and a Tafel slope of 50 mV dec−1 along with remarkable long-term stability in alkaline media. The excellent catalytic activity and stability for the OER can serve as a promising platform for the practical utilization of (CoFeNiMnCr)3O4 HEO.
Ključne besede: electrochemical water-spliting, electrocatalysts
Objavljeno v DiRROS: 20.12.2024; Ogledov: 530; Prenosov: 143
Celotno besedilo (2,75 MB)
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7. Characterization of bloom iron smelting site remains in Pržanj, SloveniaJaka Burja, Barbara Šetina, Daša Pavlovič, 2024, izvirni znanstveni članek Povzetek: This paper gives an overview of findings, connected with metallurgical activity, at the Pržanj archeological site near Ljubljana, Slovenia. More than 230 kg of slag and other remains connected with early medieval (from the 5th to the 12th century AD) metallurgical activities was found at the excavation site. The remains were grouped into four categories, i.e., furnace remains, ore, slag and a ferrous product, and analyzed in detail to obtain their chemical composition, microstructural characteristics, and mineral phase composition. The furnace wall remains, identified by their morphology and chemical composition, revealed an intensive iron processing activity at the site. The iron ore at the site was identified as goethite (FeO(OH)), a surprising find in Slovenia where limonite is typically used, and its presence suggests the potential exploitation of local bog iron ore, given the site’s geological context. Abundant slag remains at the site, identified by their shape, molten microstructure, and mineral components like wuestite, fayalite, and hercynite, indicated sophisticated smelting practices, including the use of CaO-rich materials to lower the melting temperature, a technique likely preserved from antiquity. Findings of ferrous products at ancient metallurgical sites are rare due to their value, but the discovery of a corroded iron bloom conglomerate at this site, initially mistaken for furnace remains, highlights the challenges in identifying small, corroded ferrous fragments that are often misidentified as ore. The results indicate extensive metallurgical activity at the excavation site, marking it as the first documented early medieval iron smelting production site in Slovenia.
Ključne besede: bloom iron, bloomery slag, archaeometallurgy, microstructure
Objavljeno v DiRROS: 29.07.2024; Ogledov: 612; Prenosov: 382
Celotno besedilo (4,23 MB)
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8. Influence of isothermal annealing in the 600 to 750 °C range on the degradation of SAF 2205 duplex stainless steelJaka Burja, Borut Žužek, Barbara Šetina, 2024, izvirni znanstveni članek Povzetek: We studied the effect of isothermal annealing (600–750 °C, 1 to 1000 min) on the microstructure
and mechanical properties of SAF 2205 duplex stainless steel. Impact toughness was found
to be significantly more affected than hardness by annealing. Annealing at 750 °C for 1000 min
resulted in a more than 90% decrease in impact toughness, while hardness only increased by 25%.
Tensile strength increased up to 100 MPa, but elongation decreased by more than 50% under the
same conditions. Sigma phase formation was minimal at lower temperatures (650 °C and below)
but increased significantly at higher temperatures. At 750 °C and 1000 min of annealing, the ferrite
content dropped from 50% to 16%. These findings suggest that annealing temperature and time need
to be carefully controlled to avoid a reduction in impact toughness and ductility caused by sigma
phase precipitation. The harmful effect of sigma phase precipitation on mechanical properties was
directly shown.
Ključne besede: duplex stainless steel, sigma phase, precipitation kinetics, mechanical properties, isothermal annealing
Objavljeno v DiRROS: 24.07.2024; Ogledov: 511; Prenosov: 408
Celotno besedilo (20,91 MB)
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9. Characterization of micro-threaded stem taper surface of cementless hip endoprosthesesDrago Dolinar, Boštjan Kocjančič, Klemen Avsec, Barbara Šetina, Aleksandra Kocijan, Matjaž Godec, Marko Sedlaček, Mojca Debeljak, John T. Grant, Timon Zupanc, Monika Jenko, 2024, izvirni znanstveni članek Povzetek: We investigated micro-threaded stem taper surface and its impact on premature failures, aseptic loosening, and infection in cementless hip endoprostheses. Our study focused on the fretting, and crevice corrosion of micro-threaded tapers, as well as the characterization of the microstructure and surface properties of two new and three retrieved Zweymüller stem tapers. The retrieved samples were selected and examined based on the head–stem taper interface being the sole source of modularity with a metallic component, specifically between the Ti alloy taper stem and the ceramic head. To determine the surface chemistry and microstructures of both new and retrieved hip endoprostheses stem taper titanium alloy, scanning -electron microscopy (SEM) was employed for morphological and microstructural analyses. Energy dispersive spectroscopy (EDS) was utilized for characterizing chemical element distribution, and electron backscattered diffraction (EBSD) was used for phase analysis. The roughness of the micro-threated stem tapers from different manufacturers was investigated using an optical profilometer, with standard roughness parameters Ra (average surface roughness) and Rz (mean peak to valley height of the roughness profile) being measured. Electrochemical studies revealed no fretting corrosion in retrieved stem tapers with ceramic heads. Consequently, three retrieved tapers and two new ones for comparison underwent potentiodynamic measurements in Hank’s solution to determine the corrosion rate of new and retrieved stem taper surfaces. The results showed a low corrosion rate for both new and prematurely failed retrieved samples due to aseptic loosening. However, the corrosion rate was higher in infected and low-grade infected tapers. In conclusion, our study suggests that using ceramic heads reduces taper corrosion and subsequently decreases the incidence of premature failures in total hip arthroplasty.
Ključne besede: total hip arthroplasty, stem micro-threaded taper, taper surface morphology, microstructure, corrosion, Ti implant alloy
Objavljeno v DiRROS: 06.06.2024; Ogledov: 681; Prenosov: 465
Celotno besedilo (8,47 MB)
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10. Tuning the long-term corrosion behaviour of biodegradable WE43 magnesium alloy by PEO coatingJulia Nachtsheim, Songyun Ma, Jaka Burja, Barbara Šetina, Bernd Markert, 2023, izvirni znanstveni članek Ključne besede: long-term degradation, in vitro corrosion mechanisms: biodegradable, magnesium, DMEM fluid, hydrogen evolution, PEO coating
Objavljeno v DiRROS: 20.05.2024; Ogledov: 704; Prenosov: 315
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