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2. The importance of chemical transformations of adsorbed molecules for corrosion inhibition : mercaptobenzimidazoles on copperAnton Kokalj, Erik Gregori, Barbara Kapun, Ingrid Milošev, 2025, original scientific article Abstract: This study investigates whether mercaptobenzimidazoles act as thiolates in inhibiting copper corrosion. To this end, we examined three mercaptobenzimidazole derivatives — 2-mercaptobenzimidazole (SH-BimH), 2-mercapto-1-methylbenzimidazole (SH-BimMe), and 2-(methylthio)benzimidazole (Me-S-BimH) — as corrosion inhibitors for copper in 3 wt% NaCl solution using a combined experimental and computational approach. Me-S-BimH has a thiol group (single bondSH) replaced by a methylthio group (single bondSCH ), which should prevent the formation of surface thiolates. In contrast, SH-BimMe has the same molecular formula as Me-S-BimH, but its methyl group does not cap the thiol group. Corrosion experiments reveal that after 1 h of immersion, Me-S-BimH is considerably less effective than SH-BimH and SH-BimMe at inhibiting copper corrosion. However, after 100 h of immersion, Me-S-BimH performs comparably to SH-BimH and SH-BimMe. This delayed effectiveness suggests that a molecular transformation activates Me-S-BimH over time. To explore this phenomenon, we performed a detailed DFT study of potential chemical transformations of adsorbed Me-S-BimH. Most transformations are exothermic, but only molecular deprotonation and Csingle bondS bond cleavage between the azole ring and the methylthio group exhibit sufficiently low activation barriers to occur at room temperature. Similar deprotonation and Csingle bondS bond cleavage reactions occur also for SH-BimH and SH-BimMe, leading to more strongly bound species than their intact molecular forms. Due to these transformations, Me-S-BimH and SH-BimH eventually result in the same strongly bound species, while SH-BimMe forms an analogous species. These findings may explain why, over time, all three compounds exhibit similar corrosion inhibition characteristics, and highlight the importance of chemical transformations of adsorbed molecules in corrosion inhibition.
Keywords: copper, corrosion inhibition, electrochemical measurements
Published in DiRROS: 25.08.2025; Views: 263; Downloads: 138
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3. Alumina and hafnia thin films deposited by atomic layer deposition at different temperatures on biomedical stainless steel and titaniumIvan Spajić, Sandra Drev, Urška Trstenjak, Ingrid Milošev, 2025, original scientific article Abstract: Alumina and hafnia films produced by the atomic layer deposition were applied to commercially pure Ti and stainless steel 316L specimens for protection under simulated human body conditions. The ALD films were deposited at 180 °C and 260 °C to determine how the deposition temperature affect the films' protective properties. Surface analysis of the ALD films included scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The barrier properties were tested electrochemically using potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) techniques in a simulated body solution at 37 °C. Alumina thin films showed substantial barrier properties, but after 30 days of immersion, the alumina dissolved regardless of the deposition temperature. EIS tests themselves promoted the dissolution of alumina. In contrast, the barrier properties of hafnia depended significantly on deposition temperature. Hafnia deposited at 180 °C exhibited substantial protective properties and remarkable stability over an extended immersion period. However, when deposited at 260 °C hafnia films showed strong protection at the outset, but after a few days of immersion, they lost their protective ability due to porosity. The key factors affecting the barrier properties of ALD hafnia films were the proportion of the crystalline phase and how crystallites formed.
Keywords: thin films, atomic layer deposition, titanium alloys, biomedical steel, medical implants
Published in DiRROS: 15.07.2025; Views: 420; Downloads: 237
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4. Corrosion of sintered NdFeB permanent magnetsTerezija Poženel Kovačič, Nataša Kovačević, Ingrid Milošev, 2025, review article Abstract: The green transition to reduce reliance on fossil fuel energy sources and minimise global warming is accelerating the need for NdFeB permanent magnet materials. Sintered NdFeB magnets cover the largest segment percentage within the permanent magnet type group, with a share of over 50%. The microstructure of NdFeB magnets includes grains of the Nd1+εFe4B4 (B-rich phase), which form grain boundaries with both the Nd-rich (Nd4Fe) and matrix (Nd2Fe14B) phases. NdFeB magnets are prone to degradation in harsh environments due to the low corrosion resistance of both iron and neodymium. Consequently, magnets require corrosion protection because their magnetic properties would be jeopardised due to the degradation caused by the corrosion process. Understanding magnets’ electrochemical and corrosion properties is crucial for developing their corrosion protection and thus prolonging their smooth operation in numerous industrial applications. This review aims to present the fundamental corrosion processes on sintered NdFeB magnets, provide an overview of the contemporary magnet production processes of NdFeB magnets and their impact on the corrosion resistance, and summarise the corrosion protection of NdFeB magnets. Prospects are presented, especially regarding the use of magnets in the transportation (hybrid and electric vehicles) industry and the development of alternative types of coatings.
Keywords: sintered magnets, green transition
Published in DiRROS: 03.07.2025; Views: 446; Downloads: 211
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5. Zr and Zr-Cr commercial conversion coatings deposited on 3003 aluminium alloy foilMaja Mujdrica Kim, Barbara Kapun, Ingrid Milošev, 2025, original scientific article Abstract: MAVOMcoat MC1300 (Zr-Cr-based coating) and MC1700 (Zr-based coating) on chemically pre-treated aluminium alloy 3003. Conversion times varied from 80 s to 45 min. After deposition, the samples were subjected to three post-treatments: air drying for 15 min, air drying for 24 h, and immersion in 3.5 wt% NaCl solution for 24 h. Corrosion resistance was evaluated using electrochemical measurements, whereas scanning electron microscopy with energy dispersive spectroscopy and X-ray photoelec tron spectroscopy were employed for surface analysis. Based on the evaluation of corrosion parameters, the optimal conversion times for MC1700 and MC1300 were determined to be 10 min and 7 min, respectively. The conversion coatings MC1700 and MC1300 were characterised by distinct elemental compositions, with the former predominantly comprising Zr, O, Al and F, and the latter Zr, O, Al, Cr and F. Notably, the thickness of coatings was between 10 and 170 nm, depending on the type of coating and location (matrix or intermetallic particles). The 24-hour immersion of MC1700 ZrCC in 3.5 wt% NaCl led to progressive build-up of Zr oxide and release of fluoride from the coating.
Published in DiRROS: 10.06.2025; Views: 474; Downloads: 165
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6. Composition, microstructure and corrosion resistance of DED-LB additively manufactured Ti–6Al–4V alloy : comparison with wrought alloyIngrid Milošev, Peter Rodič, Barbara Kapun, Denis Sačer, Anish Nair, Davorin Kramar, Andrej Jeromen, Edvard Govekar, 2025, original scientific article Keywords: titanium alloys, directed-energy deposition by laser beam, simulated physiological solution
Published in DiRROS: 03.06.2025; Views: 506; Downloads: 298
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7. Titanium nanostructures for biomedical applicationsMukta Vishwanath Kulkarni, Anca Mazare, Ekaterina Gongadze, Šárka Perutková, Veronika Kralj-Iglič, Ingrid Milošev, Patrik Schmuki, Aleš Iglič, Miran Mozetič, 2015, review article Published in DiRROS: 20.05.2025; Views: 384; Downloads: 144
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8. The effect of cerium ions on the structure, porosity and electrochemical properties of Si/Zr-based hybrid sol-gel coatings deposited on aluminumPeter Rodič, Jozefina Katić, Dorota Korte, Paula M. Desimone, Mladen Franko, Silvia Ceré, Mirjana Metikoš-Huković, Ingrid Milošev, 2018, original scientific article Published in DiRROS: 20.05.2025; Views: 369; Downloads: 168
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10. Risk of cancer after primary total hip replacement : the influence of bearings, cementation and the material of the stemVesna Levašič, Ingrid Milošev, Vesna Zadnik, 2018, original scientific article Abstract: Background and purpose - Despite the increasing number of total hip replacements (THRs), their systemic influence is still not known. We have studied the influence of specific features of THRs-the bearing surface, the use of bone cement and the material of the stem-on the cancer incidence. Patients and methods - In a retrospective cohort study we identified 8,343 patients with THRs performed at Valdoltra Hospital from September 1, 1997 to December 31, 2009. Patient data were linked to national cancer and population registries. The standardized incidence ratios (SIR) and Poisson regression relative risks (RR) were calculated for all and specific cancers. Results - General cancer risk in our cohort was comparable to the population risk. Comparing with population, the risk of prostate cancer was statistically significantly higher in patients with metal-on-metal bearings (SIR =1.35); with metal-on-polyethylene bearings (SIR =1.30), with non-cemented THRs (SIR =1.40), and with titanium alloy THRs (SIR =1.41). In these last 3 groups there was a lower risk of hematopoietic tumors (SIR =0.69; 0.66 and 0.66 respectively). Risk of kidney cancer was significantly higher in the non-metal-on-metal, non-cemented, and titanium alloy groups (SIR =1.30; 1.46 and 1.41 respectively). Risk of colorectal and lung cancer was significantly lower in the investigated cohort (SIR =0.82 and 0.83, respectively). Risk for all cancers combined as well as for prostate and skin cancer, shown by Poisson analysis, was higher in the metal-on-metal group compared with non-metal-on-metal group (RR =1.56; 2.02 and 1.92, respectively). Interpretation - Some associations were found between the THRs' features, especially a positive association between metal-on-metal bearings, and specific cancers.
Keywords: oncology, cancer registry, replacements, materials
Published in DiRROS: 19.05.2025; Views: 485; Downloads: 286
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