TY - JOUR A1 - Merino, E. A1 - Cere, S. A1 - Özcan Sandikcioglu, Özlem A1 - Dimper, Matthias A1 - Sobrados, I. A1 - Durán, A. A1 - Castro, Y. T1 - Influence of the BF3·O(C2H5)2 on the corrosion resistance of hybrid silica sol-gel coatings deposited on flash-PEO-treated Mg alloy N2 - Achieving highly cross-linked sol-gel coatings to provide effective corrosion protection of Mg alloys remains a challenging task. The aim of this work is to evaluate the effect boron trifluoride diethyl etherate (BF3·O(C2H5)2) as catalyst to epoxy group in a GPTMS/TEOS/SiO2 sol and assesses its effect on the structure and corrosion resistance properties of Flash-PEO coated pre-treated Mg alloy. 29Si MAS NMR and 13C CPMAS-NMR demonstrated that (BF3·O(C2H5)2) efficiently promotes the epoxy polymerization of the GPTMS and the formation of a hybrid silica network. However, the amount of (BF3·O(C2H5)2) should be optimized to minimize the formation of undesirable byproducts such as ethyl ether terminal units. Therefore, GPTMS/TEOS/SiO2 sols containing different amounts of (BF3·O(C2H5)2) were synthesized and deposited onto the Flash-PEO coated Mg alloy, leading to bilayer systems with a total thickness of ⁓8 μm. The corrosion behavior of the bilayer coatings in 3.5 wt% NaCl solution was evaluated by electrochemical impedance spectroscopy (EIS) and Scanning Kelvin probe microscope (SKPFM). The results revealed that the barrier properties of the coatings with enhanced cross-linked structure showed impedance modulus (│Z│f:0.1 Hz) approximately four orders of magnitude higher than the bare magnesium alloy and two orders of magnitude higher than the F-PEO coated sample. A suitable compromise between (BF3·O(C2H5)2) amount and sol-gel film structure is required to obtain a more durable barrier coating capable to extend the protective lifespan of the magnesium alloy. KW - Sol-gel KW - Corrosion KW - AZ31B Mg alloy KW - Chemical structure KW - SKPFM PY - 2026 DO - https://doi.org/10.1016/j.surfcoat.2025.133055 SN - 0257-8972 VL - 522 SP - 1 EP - 13 PB - Elsevier B.V. AN - OPUS4-65416 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Valet, Svenja A1 - Bohlmann, Tatjana A1 - Ebell, Gino A1 - Burkert, Andreas T1 - pH sensitive gel pads for the visualization of anodes and cathodes on zinc N2 - Zinc and zinc alloys have many applications. Zinc corrosion takes place in the atmosphere and is assumed to follow the water drop theory (a macroelement), in which the anode is at the centre of the drop and is surrounded by a cathode. This paper is the first to use gel electrolytes made of agar to visualize anodic and cathodic areas on zinc samples in order to examine the water drop theory. For that, agar gels were added with universal pH indicators, as the anode and cathode exhibit different pH values. In this paper, different amounts of pH indicators were tested to determine whether the indicator influences the potential, the impedance, phase shift, corrosion current and potential and corrosion layer resistance. KW - Corrosion KW - Zinc KW - Gel electrolyte PY - 2026 DO - https://doi.org/10.1016/j.electacta.2026.148134 SN - 0013-4686 VL - 551 SP - 1 EP - 21 PB - Elsevier Ltd. AN - OPUS4-65308 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tidblad, Johan A1 - Moya Núñez, Alice A1 - de la Fuente, Daniel A1 - Ebell, Gino A1 - Flatlandsmo Berglen, Tore A1 - Grøntoft, Terje A1 - Hans, Ulrik A1 - Christodoulakis, Ioannis A1 - Kajánek, Daniel A1 - Kreislová, Kateřina A1 - Kwiatkowski, Lech A1 - La Torreta, Teresa A1 - Lutze, Rafał A1 - Pinar Larrubia, Guadalupe A1 - Pintus, Valentina A1 - Prange, Michael A1 - Spezzano, Pasquale A1 - Varotsos, Costas A1 - Verney-Carron, Aurélie A1 - Vuorio, Tiina A1 - Yates, Tim T1 - Corrosion and Soiling in the 21st Century: Insights from ICP Materials and Impact on Cultural Heritage N2 - This paper reviews results published by the International Co-operative Programme on Effects on Materials including Historic and Cultural Monuments (ICP Materials) with emphasis on those obtained after the turn of the century. Data from ICP Materials come from two main sources. The first is through exposures of materials and collection of environmental data in a network of atmospheric exposure test sites mainly distributed across Europe. Corrosion of carbon steel has continued to decrease during the period 2000–2020 but corrosion of zinc only up until 2014, and the trend in zinc corrosion is only visible when examining four-year data. Surface recession of limestone as well as soiling of modern glass show no decreasing trend during 2000–2020. The second is through case studies performed at heritage sites across Europe. Risk analysis of corrosion and soiling for twenty-six sites indicate that currently soiling is a more significant maintenance trigger than corrosion. Costs for maintaining heritage sites are substantial and costs attributable to air pollution is estimated from 40% to as much as 80% of the total cost. Future directions of the program are work on effects of particulate matter, improving the scientific basis for the work, and making the monitoring data publicly available. KW - Corrosion KW - Atmospheric corrosion KW - Soiling PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644651 DO - https://doi.org/10.3390/cmd6040054 SN - 2624-5558 VL - 6 IS - 4 SP - 1 EP - 25 PB - MDPI AG AN - OPUS4-64465 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Manzoni, Anna Maria A1 - Mohring, Wencke A1 - Schneider, Mike A1 - Laplanche, Guillaume A1 - Hagen, Sebastian Peter A1 - Stephan‐Scherb, Christiane T1 - High‐Temperature Oxidation of the CrFeNi Medium‐Entropy Alloy N2 - The isothermal high‐temperature oxidation behavior of the equiatomic CrFeNi medium‐entropy alloy is a key issue that determines whether this material is suited for high‐temperature application. In this view, the understanding of the long‐term behavior is even more crucial than short‐term corrosion effects. Herein, a single‐phase CrFeNi alloy of the face‐centered‐cubic structure is exposed to synthetic air at 1000, 1050, and 1100 °C for 24, 100, and 1000 h and its oxidation behavior is systematically compared to that of 316L steel, which shows a surprising initial oxidation stabilization during early stages. The oxidation rate of CrFeNi is parabolic at 1000 °C (with a parabolic constant kp = 1.4·10−5 mg−2 cm−4 s−1) and 1050 °C (kp = 2.7·10−5 mg−2 cm−4 s−1), but breakaway oxidation occurs at 1100 °C after 4 h of exposure. In all cases, the oxide scales are found to (at least) partially spall off. Chromium diffuses outward to form a Cr2O3 layer at the gas/oxide interface, and a thin layer of (Cr, Fe, Ni)3O4 is identified at the oxide/alloy interface. Unlike the 316L alloy, which contains more Mn and Fe, the CrFeNi alloy does not show any catastrophic oxidation behavior at the investigated conditions. KW - Corrosion KW - Medium-entropy alloy KW - Scanning electron microscopy PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-636672 DO - https://doi.org/10.1002/adem.202500400 SN - 1438-1656 SP - 1 EP - 14 PB - Wiley VHC-Verlag AN - OPUS4-63667 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ebell, Gino A1 - Seifert, Lando A1 - Burkert, Andreas T1 - Innovative Korrosionsprüfung für Beton- und Spannstähle T1 - Test methods for corrosion testing of reinforcing and prestressing steels N2 - Korrosion ist einer der maßgeblichen Schädigungsmechanis-men im Stahlbetonbau und limitiert die Nutzungsdauer vonInfrastrukturbauwerken zum Teil erheblich. Dabei differenziertman zwischen verschiedenen Korrosionsvarianten, Korrosioninfolge Karbonatisierung des Betons, chloridinduzierte Korro-sion an Meerwasserbauwerken oder durch Tausalzbelastungund im Fall von Spannstahlbauwerken kann zusätzlich was-serstoffinduzierte Spannungsrisskorrosion (SpRK) auftreten.Für den Einsatz alternativer Betonstähle wie nichtrostenderBetonstahl gilt es, die Höhe des kritischen korrosionsaus-lösenden Chloridgehalts zu bestimmen. Um diesen für diejeweiligen Betonstähle zu ermitteln, fehlen bislang jedochnormativ geregelte Prüfverfahren. Die Empfindlichkeit vonSpannstählen gegenüber SpRK bedarf gemäß aktueller Nor-mung Langzeit-Auslagerungstests, die eine werkseigeneProduktionskontrolle aufgrund der langen Prüfzeiten nahezuunmöglich machen. Ein neu entwickeltes Prüfverfahren unterAnwendung kathodischer Polarisation, das inzwischen imneusten Entwurf der DIN EN ISO 15630–3 aufgenommenwurde, ermöglicht eine Bewertung der SpRK-Empfindlichkeitfür Spanndrähte innerhalb von 24 Stunden. Die Ergebnissetragen zur Verbesserung der Lebensdauerabschätzung undzur Weiterentwicklung von Normen für korrosionsbeständigeBetonstähle und der Robustheitsbewertung von Spannstählenbei. N2 - Corrosion is a primary damage mechanism in reinforced concrete construction, significantly reducing the service life of infrastructure. A categorisation of corrosion is imperative for the comprehension of the subject. The corrosion of concrete can be attributed to the carbonation process, whilst chloride-induced corrosion is prevalent in structures exposed to seawater or by de-icing salt. Additionaly to the former corrosion processe, prestressing steel structures could be also highly susceptible to hydrogen-induced stress corrosion cracking (SCC). In order to utilise alternative reinforcing steels, such as stainless reinforcing steel, it is necessary to ascertain the level of critical chloride threshold that can induce corrosion. Nevertheless, there is an absence of standardised test methods for determining this for the respective reinforcing steels to date. Acc. to current standardization, the sensitivity of prestressing steels to chromium content necessitates long-term ageing tests, which impede in-house production control due to the extended testing times. However, a newly developed test method using cathodic polarization, which has now been included in the latest draft of DIN EN ISO 15630–3, makes it possible to assess the susceptibility of prestressing steels to corrosion cracking within 24 hours. The results of this study will contribute to the improvement of service life estimation and the further development of standards for corrosion-resistant reinforcing steels and the robustness assessment of prestressing steels. KW - Korrosion KW - Spannstahl KW - Nichtrostender Betonstahl KW - Corrosion KW - Prestressing steel KW - Stainless reinforcing steel KW - Wasserstoff KW - Spannungsrisskorrosion KW - Lochkorrosion KW - Hydrogen KW - Stress corrosion cracking KW - Pitting corrosion PY - 2025 DO - https://doi.org/10.1002/best.202500025 SN - 0005-9900 SN - 1437-1006 SP - 1 EP - 8 PB - Ernst CY - Berlin AN - OPUS4-63305 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Malefioudaki, Mariella A1 - Misra, Archismita A1 - Sbeity, Nadja A1 - Zueco-Vincelle, Juan A1 - Laguna-Bercero, Miguel A. A1 - Koerdt, Andrea A1 - Martín-Rapún, Rafael A1 - Mitchell, Scott G. T1 - Multifunctional polyoxomolybdate ionic liquid coatings for mitigating microbiologically influenced corrosion N2 - Corrosion of metals and other materials in marine environments poses significant economic, operational, safety, and environmental challenges across the oil and gas industry, the renewable energy sector, and maritime infrastructure. Microbiologically influenced corrosion (MIC) accounts for a substantial portion of this corrosion, with sulfate-reducing bacteria (SRB) and methanogenic archaea (MA) being key contributors. Conventional methods such as cathodic polarization have proven insufficient in mitigating the colonization of corrosive microbial communities in real marine environments, requiring the development of alternative, broad-spectrum antimicrobial strategies to prevent such biofilm formation. Recently, molybdate has emerged as a potential alternative to traditional biocides and nitrate. Our hypothesis is polyoxometalate-ionic liquids (POM-ILs), which exhibit antimicrobial and anticorrosion properties, could have a broader spectrum of antimicrobial activity than demonstrated until now and could be capable of shielding and protecting sensitive metal surfaces from the extreme acidic environments produced by MIC microorganisms. Here we show how two prototype polyoxomolybdate-based POM-ILs, [(CH3(CH2)6)4N]2[Mo6O19] and [(CH3(CH2)6)4N]4[Mo8O26], demonstrated antimicrobial activity at microgram per millilitre concentrations, prevented biofilm formation on metal surfaces, and provided resistance to corrosive acidic environments. Furthermore, impedance measurements were commensurate with electron microscopy studies showing that POM-IL-coated brass coupons withstood extremely corrosive environments. These proof-of-concept results demonstrate how multi-functional POM-IL coatings represent promising MIC mitigation solutions by providing a hydrophobic acid-resistant and biocidal protective layer that prevents biocolonisation and acidic corrosion by MIC microorganisms. KW - Polyoxometalates KW - Ionic liquid KW - Microbiologically influenced corrosion KW - Corrosion KW - Heritage preservation PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631951 DO - https://doi.org/10.1039/d5mh00373c SN - 2051-6347 VL - 12 IS - 13 SP - 4648 EP - 4661 PB - Royal Society of Chemistry (RSC) CY - Cambridge AN - OPUS4-63195 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heyn, A. A1 - Kotula, Stefan A1 - Ebell, Gino A1 - Babutzka, M. T1 - Results of a Round Robin Test for the Determination of Polarization Resistances on Differently Weathered Zinc Samples Using Gel Electrolytes N2 - This article presents the results of a round robin test throughout Germany with 19 participating institutions. Corrosion productlayer resistances (RL ) were determined on two differently weathered pure zinc samples and a sample activated with NaOH bymeans of electrochemical measurement of the linear polarization resistance (LPR) using agar‐based gel electrolytes. The roundrobin test was organized by the Bundesanstalt für Materialforschung und ‐prüfung (BAM) in Berlin. The measurements werecarried out by the participants in the period from May to July 2021. The results are summarized in this article comprising anassessment of the reproducibility and repeatability of the measurements. The methodology is suitable for distinguishing zincsurfaces after exposure to different atmospheres based on the corrosion product layer resistances (RL). In addition, possibleproblems in the application of the method were identified, and solutions for improving reproducibility and repeatability arediscussed. The results and knowledge from the round robin test are incorporated into a new test standard (DIN 50023:2024‐07)for this measurement method KW - Corrosion PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630546 DO - https://doi.org/10.1002/maco.202414696 SN - 1521-4176 SP - 1 EP - 12 PB - Wiley AN - OPUS4-63054 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ebell, Gino A1 - Tannert, S. A1 - Lehmann, Jens A1 - Müller, H. T1 - Offshore Weathering Campaign on a North Sea Wind Farm Part One: Corrosivity Categories N2 - The aim of this study is to investigate the corrosion behavior of materials and coatings in offshore environments, with a focus on determining the corrosivity categories at different locations on wind turbines. The collaboration between the authors enabled a 3‐year weathering campaign at the Hohe See and Albatros offshore wind farms in the North Sea. Metal panels were installed on two wind turbines to assess the corrosivity of different atmospheric conditions. Preliminary results indicate significant variations in corrosivity depending on location and material used, suggesting that current standards may not fully reflect real‐world conditions. The results of the study will help to optimize material selection and corrosion protection strategies for offshore wind farms, potentially extending their lifetime and reducing operating costs. KW - Corrosion KW - Offshore KW - Wind PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628995 DO - https://doi.org/10.1002/maco.202414711 SN - 1521-4176 SP - 1 EP - 10 PB - Wiley CY - Weinheim AN - OPUS4-62899 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pfennig, Anja A1 - Mohring, Wencke A1 - Wolf, Marcus T1 - The insignificant improvement of corrosion and corrosion fatigue behavior in geothermal environment applying Boehmit coatings on high alloyed steels N2 - The efficacy of alumina-sol based coatings in a water-free atmosphere at high temperatures suggests a potential solution for enhancing the corrosion resistance of high-alloyed steels in Carbon Capture and Storage (CCS) environments. In this study, coupons of X20Cr13, designed for use as injection pipes with 13% Chromium and 0.20% Carbon (1.4021, AISI 420), were sol-gel coated with water and ethanol-based alumina. These coated coupons were then exposed to CO2-saturated saline aquifer water, simulating conditions in the Northern German Basin, for 1000 h at ambient pressure and 60 °C. Corrosion fatigue experiments were also conducted using specimens of X5CrNiMoCuNb16-4 (1.4542, AISI 630), a suitable candidate for geothermal applications, to assess the impact of the ethanol-based coating on the number of cycles to failure at different stress amplitudes. Unfortunately, the coating exhibited early spallation, resulting in corrosion kinetics and corrosion fatigue data identical to those of uncoated specimens. Consequently, the initially promising Boehmit coating is deemed unsuitable for CCS applications and further research therefore not advisable. KW - Alumina coating KW - High alloyed steel KW - Pitting KW - Surface corrosion KW - CO2 KW - Pipeline KW - Corrosion KW - CCS KW - CO2-storage PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623786 DO - https://doi.org/10.3390/app14041575 SN - 2076-3417 VL - 14 IS - 4 SP - 1 EP - 12 PB - MDPI CY - Basel AN - OPUS4-62378 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, Runze A1 - Sur, Debashish A1 - Li, Kangming A1 - Witt, Julia A1 - Black, Robert A1 - Whittingham, Alexander A1 - Scully, John R. A1 - Hattrick-Simpers, Jason T1 - Bayesian assessment of commonly used equivalent circuit models for corrosion analysis in electrochemical impedance spectroscopy N2 - Electrochemical Impedance Spectroscopy (EIS) is a crucial technique for assessing corrosion of metallic materials. The analysis of EIS hinges on the selection of an appropriate equivalent circuit model (ECM) that accurately characterizes the system under study. In this work, we systematically examined the applicability of three commonly used ECMs across several typical material degradation scenarios. By applying Bayesian Inference to simulated corrosion EIS data, we assessed the suitability of these ECMs under different corrosion conditions and identified regions where the EIS data lacks sufficient information to statistically substantiate the ECM structure. Additionally, we posit that the traditional approach to EIS analysis, which often requires measurements to very low frequencies, might not be always necessary to correctly model the appropriate ECM. Our study assesses the impact of omitting data from low to medium-frequency ranges on inference results and reveals that a significant portion of low-frequency measurements can be excluded without substantially compromising the accuracy of extracting system parameters. Further, we propose simple checks to the posterior distributions of the ECM components and posterior predictions, which can be used to quantitatively evaluate the suitability of a particular ECM and the minimum frequency required to be measured. This framework points to a pathway for expediting EIS acquisition by intelligently reducing low-frequency data collection and permitting on-the-fly EIS measurements. KW - Electrochemical Impedance Spectroscopy (EIS) KW - MAPz@BAM KW - Bayesian Inference KW - Corrosion PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623392 DO - https://doi.org/10.1038/s41529-024-00537-8 VL - 8 SP - 120 PB - Springer Materials AN - OPUS4-62339 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -