1. Comparative evaluation of corrosion resistance of AISI 316L and Ti6Al4V dental materials under simulated inflammatory conditionsMojca Slemnik, 2025, original scientific article Abstract: Titanium and its alloys, as well as stainless steel, are commonly used materials for implants in the human body due to their excellent biocompatibility, corrosion resistance, and mechanical properties. However, the long-term performance of these materials in the oral cavity can be affected by the complex oral environment, including the ingestion of food, beverages, and oral hygiene products, leading to the presence of various ions, pH fluctuations, and inflammatory processes. In this study, the corrosion properties of two biocompatible materials, Ti6Al4V and AISI 316L stainless steel, are investigated under varying oral inflammatory conditions. Using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), SEM, and EDS analysis, the corrosion behaviour of both materials was analysed in environments simulating mild and severe inflammation. Results indicate that Ti6Al4V exhibits superior corrosion resistance at low H2O2 concentrations mimicking mild inflammation, with significantly lower corrosion rates compared to AISI 316L. However, at higher H2O2 concentrations, which correspond to severe inflammation, AISI 316L shows better resistance despite its susceptibility to pitting corrosion. Both alloys show reduced passivation after 72 h, with corrosion products accumulating on the surface after 96 h, contributing to repassivation. These results emphasise the need for individualized material selection in dental applications based on a patient’s susceptibility to oral inflammation.
Keywords: corrosion, EIS, inflammatory conditions, titanium, stainless steel, dental materials
Published in DKUM: 19.05.2025; Views: 0; Downloads: 2
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2. A HepG2 cell-based biosensor that uses stainless steel electrodes for hepatotoxin detectionMartin Rozman, Zala Štukovnik, Ajda Sušnik, Amirhossein Pakseresht, Matej Hočevar, Damjana Drobne, Urban Bren, 2022, original scientific article Abstract: Humans are frequently exposed to environmental hepatotoxins, which can lead to liver
failure. Biosensors may be the best candidate for the detection of hepatotoxins because of their high
sensitivity and specificity, convenience, time-saving, low cost, and extremely low detection limit. To
investigate suitability of HepG2 cells for biosensor use, different methods of adhesion on stainless
steel surfaces were investigated, with three groups of experiments performed in vitro. Cytotoxicity
assays, which include the resazurin assay, the neutral red assay (NR), and the Coomassie Brilliant Blue
(CBB) assay, were used to determine the viability of HepG2 cells exposed to various concentrations of
aflatoxin B1 (AFB1) and isoniazid (INH) in parallel. The viability of the HepG2 cells on the stainless
steel surface was quantitatively and qualitatively examined with different microscopy techniques. A
simple cell-based electrochemical biosensor was developed by evaluating the viability of the HepG2
cells on the stainless steel surface when exposed to various concentrations of AFB1 and INH by using
electrochemical impedance spectroscopy (EIS). The results showed that HepG2 cells can adhere to the
metal surface and could be used as part of the biosensor to determine simple hepatotoxic samples.
Keywords: HepG2 cell line, impedance biosensor, adhesion, hepatotoxins, stainless steel
Published in DKUM: 10.04.2025; Views: 0; Downloads: 12
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3. Strain rate-dependent compressive properties of bulk cylindrical 3D-printed samples from 316L stainless steelMichaela Neuhauserova, Petr Koudelka, Tomáš Fíla, Jan Falta, Václav Rada, Jan Sleichrt, Petr Zlámal, Anja Mauko, Ondřej Jiroušek, 2022, original scientific article Abstract: The main aim of the study was to analyse the strain rate sensitivity of the compressive
deformation response in bulk 3D-printed samples from 316L stainless steel according to the printing
orientation. The laser powder bed fusion (LPBF) method of metal additive manufacturing was
utilised for the production of the samples with three different printing orientations: 0◦
, 45◦
, and 90◦
.
The specimens were experimentally investigated during uni-axial quasi-static and dynamic loading.
A split Hopkinson pressure bar (SHPB) apparatus was used for the dynamic experiments. The
experiments were observed using a high-resolution (quasi-static loading) or a high-speed visible-light
camera and a high-speed thermographic camera (dynamic loading) to allow for the quantitative and
qualitative analysis of the deformation processes. Digital image correlation (DIC) software was used
for the evaluation of displacement fields. To assess the deformation behaviour of the 3D-printed
bulk samples and strain rate related properties, an analysis of the true stress–true strain diagrams
from quasi-static and dynamic experiments as well as the thermograms captured during the dynamic
loading was performed. The results revealed a strong strain rate effect on the mechanical response of
the investigated material. Furthermore, a dependency of the strain-rate sensitivity on the printing
orientation was identified.
Keywords: 3D printing, laser powder bed fusion, 316L stainless steel, printing direction, split Hopkinson pressure bar
Published in DKUM: 20.03.2025; Views: 0; Downloads: 12
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4. Flower-like superhydrophobic surfaces fabricated on stainless steel as a barrier against corrosion in simulated acid rainRegina Fuchs-Godec, 2022, original scientific article Abstract: Functionalisation of the metal surface of low-carbon ferritic stainless steel (from hydrophilic to hydrophobic properties) was achieved by flower-like hierarchical structures on a steel substrate prepared by a low-cost immersion method. The flower-like structured hydrophobic layers on the steel substrate were obtained by immersing the samples in an ethanolic solution of stearic acid with the addition of various concentrations of expired vitamin E ((+)α-tocopherol). The stability and corrosion-inhibiting effect of the hierarchically structured (such as natural cornflower) hydrophobic layers were studied systematically during short and long immersion tests, 120 h (five days) in an acidic environment (pH = 3) using potentiodynamic measurements, electrochemical impedance spectroscopy and chronopotentiometry. The surfaces of the samples, their wettability, surface morphology and chemical composition were characterised by contact angle measurements, SEM, ATR-FTIR and EDAX. After 120 h of immersion, the inhibition efficiency of the flower-like structured hydrophobic layers on the steel substrate in the selected corrosion medium remained above 99%, and the hierarchical structure (flower-like structure) was also retained on the surface.
Keywords: acid rain, corrosion, flower-like structure, inhibition, stainless steel
Published in DKUM: 05.12.2024; Views: 0; Downloads: 10
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5. Effect of residual stresses on the fatigue stress range of a pre-deformed stainless steel AISI 316L exposed to combined loadingDarko Jagarinec, Nenad Gubeljak, 2024, original scientific article Abstract: AISI 316L austenitic stainless steel is utilized in various processing industries, due to its abrasion resistance, corrosion resistance, and excellent properties over a wide temperature range. The physical and mechanical properties of a material change during the manufacturing process and plastic deformation, e.g., bending. During the combined tensile and bending loading of a structural component, the stress state changes due to the residual stresses and the loading range. To characterize the component’s stress state, the billet was bent to induce residual stress, but a phase transformation to martensite also occurred. The bent billet was subjected to combined tensile–bending and fatigue loading. The experimentally measured the load vs. displacement of the bent billet was compared with the numerical simulations. The results showed that during fatigue loading of the bent billet, both the initial stress state at the critical point and the stress state during the dynamic loading itself must be considered. Analysis was demonstrated only for one single critical point on the surface of the bent billet. The residual stresses due to the phase transformation of austenite to martensite affected the range and ratio of stress. The model for the stress–strain behaviour of the material was established by comparing the experimentally and numerically obtained load vs. displacement curves. Based on the description of the stress–strain behaviour of the pre-deformed material, guidelines have been provided for reducing residual tensile stresses in pre-deformed structural components.
Keywords: metastable austenitic stainless steel, fatigue, residual stress, phase transformation
Published in DKUM: 28.11.2024; Views: 0; Downloads: 20
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6. The influence of the ratio of circumference to cross-sectional area of tensile bars on the fatigue life of additive manufactured AISI 316L steelLuka Ferlič, Filip Jerenec, Mario Šercer, Igor Drstvenšek, Nenad Gubeljak, 2024, original scientific article Abstract: The static and dynamic loading capacities of components depend on the stress level to which the material is exposed. The fatigue behavior of materials manufactured using additive technology is accompanied by a pronounced scatter between the number of cycles at the same stress level, which is significantly greater than the scatter from a material with the same chemical composition, e.g., AISI 316L, but produced by rolling or forging. An important reason lies in the fact that fatigue cracks are initiated almost always below the material surface of the loaded specimen. Thus, in the article, assuming that a crack will always initiate below the surface, we analyzed the fatigue behavior of specimens with the same bearing cross section but with a different number of bearing rods. With a larger number of rods, the circumference around the supporting part of the rods was 1.73 times larger. Thus, experimental fatigue of specimens with different sizes showed that the dynamic loading capacity of components with a smaller number of bars is significantly greater and can be monitored by individual stress levels. Although there are no significant differences in loading capacity under static and low-cycle loading of materials manufactured with additive technologies, in high-cycle fatigue it has been shown that the ratio between the circumference and the loading cross section of tensile-loaded rods plays an important role in the lifetime. This finding is important for setting a strategy for manufacturing components with additive technologies. It shows that a better dynamic loading capacity can be obtained with a larger loading cross section.
Keywords: AISI 316L stainless steel, additive manufacturing, FEM, high-cycle fatigue, fractography analysis
Published in DKUM: 25.11.2024; Views: 0; Downloads: 28
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7. The influence of delta ferrite on the quality assessment of austenitic stainless steel welds for the production of ovensZdravko Praunseis, 2020, original scientific article Abstract: Rust-resistant metals, such as the popular stainless steel, often contain some quantities of delta ferrite that lower the mechanical properties of welded joints. The results of the study show that the amount of ferrite influences the quality assessment of austenitic stainless steel welds for the production of ovens using the resistance seam welding process. In this article, the basic device of resistance seam welding for the production of stainless steel welds is described. The device itself will have a significant role in the operation of the line; therefore, it was very precisely constructed and designed.
Keywords: austenitic stainless steel, delta ferrite, quality assessment, welded joints, production of ovenss
Published in DKUM: 15.11.2023; Views: 421; Downloads: 53
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8. Amoxicillin doped hyaluronic acid/fucoidan multifunctional coatings for medical grade stainless steel orthopedic implantsMatej Bračič, Sanja Potrč, Matjaž Finšgar, Lidija Gradišnik, Uroš Maver, Hanna Budasheva, Dorota Korte, Mladen Franko, Lidija Fras Zemljič, 2023, original scientific article Abstract: This work investigated the potential of amoxicillin-doped hyaluronic acid/fucoidan multifunctional coatings on medical grade stainless steel as biocompatible, osteointegration enhancing, antimicrobial, and bacterial biofilm inhibiting coatings for orthopedic implants. The coatings were prepared by layer-by-layer spin coating and confirmed by optical contact angle goniometry and infrared spectroscopy. Time-of-flight secondary ion mass spectrometry showed a homogeneous distribution of the individual layers. In contrast, thermal diffusivity, and thermal conductivity measurements by photothermal beam deflection spectrometry showed diffusion of the amoxicillin into the hyaluronic acid and fucoidan layers. In vitro release of amoxicillin showed complete release within one hour, as reflected by the formation of inhibition zones against Staphylococcus aureus and Escherichia coli. Synergistic effects were observed between the hyaluronic acid and amoxicillin in inhibiting S.Aureus biofilm, and between the fucoidan and amoxicillin in improving the antioxidant properties by an ABTS radical scavenging assay. Biocompatibility was determined with human osteoblasts, confirming the potential of such multifunc- tional coatings to enhance the bioactivity of steel-based orthop edic implants.
Keywords: orthopedic implant, medical grade stainless steel, amoxicillin, hyaluronic acid, fucoidan, multifunctional coating
Published in DKUM: 18.08.2023; Views: 588; Downloads: 171
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9. The influence of $Ce^{3+}$ ions on the corrosion rate of stainless steel in acidic solutions of different pH-valuesAljana Petek, Sebastijan Kovačič, 2014, original scientific article Abstract: The corrosion resistance of AISI 420 stainless steel in 0.1 mol $L^{−1}$ $H_2SO_4$ + 0.1 mol $L^{−1}$ $Na_2SO_4$ solutions at different pH-values and the inhibiting effect of $Ce^{3+}$ ions was studied using electrochemical polarization methods. The results reveal decreasing of the corrosion rate with an increasing the pH of the solution, which demonstrates the progressive protective character of the inhibitor used. At pH lower than 3.33, the corrosion inhibition was most probably a result of the competitive adsorption of $Ce^{3+}$ with $H^+$ ions on the cathodic sites of the electrode surface, and it was found to be dependent on the relative concentration of $H^+$/$Ce^{3+}$. The peroxide generated from the oxygen reduction reaction at pH 3.33 was found to be capable oxidize trivalent cerium (Ce) to the tetravalent state. As obtained hydroxide precipitates act as diffusion barrier hindering the corrosion processes, whereafter a spontaneous passivity occurs on the steel surface at this pH.
Keywords: acid corrosion, green corrosion inhibitor, stainless steel, electrochemical techniques
Published in DKUM: 24.07.2017; Views: 1416; Downloads: 390
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10. Novel chitosan/diclofenac coatings on medical grade stainless steel for hip replacement applicationsMatjaž Finšgar, Amra Perva, Janja Stergar, Lidija Gradišnik, Uroš Maver, 2016, original scientific article Abstract: Corrosion resistance, biocompatibility, improved osteointegration, as well the prevention of inflammation and pain are the most desired characteristics of hip replacement implants. In this study we introduce a novel multi-layered coating on AISI 316LVM stainless steel that shows promise with regard to all mentioned characteristics. The coating is prepared from alternating layers of the biocompatible polysaccharide chitosan and the non-steroid anti-inflammatory drug (NSAID), diclofenac. Electrochemical methods were employed to characterize the corrosion behavior of coated and uncoated samples in physiological solution. It is shown that these coatings improve corrosion resistance. It was also found that these coatings release the incorporated drug in controlled, multi-mechanism manner. Adding additional layers on top of the as-prepared samples, has potential for further tailoring of the release profile and increasing the drug dose. Biocompatibility was proven on human-derived osteoblasts in several experiments. Only viable cells were found on the sample surface after incubation of the samples with the same cell line. This novel coating could prove important for prolongation of the application potential of steel-based hip replacements, which are these days often replaced by more expensive ceramic or other metal alloys.
Keywords: corrosion, corrosion resistance, chitosan, biocompatibility, biomaterials, biomedical materials, coatings, stainless steel
Published in DKUM: 23.06.2017; Views: 2073; Downloads: 400
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