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 - 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 - Valet, Svenja A1 - Bohlmann, Tatjana A1 - Burkert, Andreas A1 - Ebell, Gino T1 - Zinc acetate containing gel pads for electrochemical measurements of Zn samples N2 - Agar gel pads have been used for electrochemical measurements for some time. For zinc in particular, a standard method for measuring the stability of the corrosion product layer is being established. The main interpretation factor is the corrosion product layer resistance RL, as it is easy to determine and interpret. A high corrosion product layer resistance indicates a high level of protection. However, it is not yet known how low the corrosion product layer resistance is for freshly produced zinc samples. As zinc is highly active, it reacts immediately with the environment to form a corrosion product layer, which affects the corrosion product layer resistance. The addition of zinc acetate to the agar gel pads prevents the formation of a surface layer and destroys existing ones. This makes it possible to measure an almost corrosion product-free zinc surface. This is important in defining the range of corrosion product layer resistance for a protective surface. KW - Electrochemistry KW - General Chemical Engineering KW - Analytical Chemistry KW - Corrosion KW - Zinc KW - Korrosion PY - 2023 DO - https://doi.org/10.1016/j.jelechem.2023.117814 SN - 1572-6657 VL - 948 SP - 1 EP - 8 PB - Elsevier B.V. AN - OPUS4-59079 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Valet, Svenja A1 - Burkert, Andreas A1 - Ebell, Gino A1 - Babutzka, Martin T1 - Determination of the corrosion product layer resistance on zinc and electrolytically galvanized steel samples by using gel electrolytes N2 - Although zinc and zinc coatings have been widely used for corrosion protection for decades new zinc coatings are constantly being developed. Characterizing the corrosion protectiveness of these new coatings, however, should not be underestimated. While exposure tests are time intensive, cyclic tests can only be used for a very limited field of application. Thus, electrochemical measurements provide both an efficient and an effective alternative. Conventional aqueous bulk electrolytes influence the surface layers of a tested zinc coating and are therefore not reliable. Gel electrolytes, however, have evolved over the last few years, are minimally invasive and provide reliable results. This work describes experiments with gel electrolytes made of agar. Unlike previous work, it proposes a composition of gel electrolyte for minimally invasive description of the protective power of naturally formed oxide layers on zinc and zinc coatings. Therefore, as a first part, the gel electrolyte made of agar is verified as a method for zinc and zinc-coated samples. Afterwards, this paper introduces the corrosion product layer resistance RL as a promising parameter to evaluate the protective power of zinc coatings. Results are verified with EIS and FTIR measurements. An example on a representative zinc coating demonstrates the practical application. KW - Gel electrolytes KW - Agar KW - Zinc coatings KW - Atmospheric exposure KW - Corrosion PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526053 DO - https://doi.org/10.1016/j.electacta.2021.138191 SN - 0013-4686 VL - 385 SP - 138191 PB - Elsevier Ltd. AN - OPUS4-52605 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Babutzka, Martin A1 - Müller, Thoralf A1 - Mietz, Jürgen A1 - Burkert, Andreas T1 - Investigation of the influence of iron‐containing abrasives on the corrosion behaviour of the aluminium alloy AlSi1.2Mg0.4 N2 - The corrosion resistance of aluminium surfaces is closely linked to the surfacecstate after a grinding process. For years, iron‐containing abrasive materials were suspected to lead to increased corrosion susceptibility after processing of aluminium surfaces. To prove a possible correlation between the iron content of an abrasive and the corrosion behaviour of aluminium components, scientific investigations and experimentally practical corrosion tests are necessary. For the current investigation, specimens of a technical Al‐Si alloy from the same batch were used. The test specimens were mechanically ground with various resin‐bonded model abrasives containing different iron contents. The performed corrosion tests did not reveal a negative influence of the different iron‐containing abrasives on the corrosion behaviour of the Al–Si alloy. However, the most sensitive measuring method (electrochemical noise) showed differences in the surface activity depending on the type of abrasive. KW - Aluminium KW - Corrosion KW - Corrosion testing KW - Grinding PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506762 DO - https://doi.org/10.1002/maco.202011657 SN - 0947-5117 SN - 1521-4176 VL - 71 IS - 10 SP - 1667 EP - 1679 PB - Wiley‐VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-50676 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reinemann, Steffi A1 - Rosemann, P. A1 - Babutzka, Martin A1 - Lehmann, Jens A1 - Burkert, Andreas T1 - Influence of grinding parameters on the corrosion behavior of austenitic stainless steel N2 - Samples of the austenitic stainless steel grade X5CrNi18‐10 (1.4301, AISI 304) were ground industrially with various grinding parameters to study their influence on corrosion resistance. The ability of the mechanically ground surfaces to form a stable passive layer was evaluated by KorroPad test and a modified electrochemical potentiodynamic reactivation test based on a single loop (EPR‐SL). Furthermore, the surfaces were characterized by surface analytical methods. The main influence was determined regarding abrasive belt type. Surfaces mechanically ground with granulate abrasive belts constantly had a lower corrosion resistance than surfaces ground with single‐coated grain. The granulate abrasive belts generated more sensitized surface areas and left formations of welded sample material on the mechanically ground surfaces. A post‐treatment with a nonwoven abrasive proved to be an effective finishing process by which the surface defects and sensitized material got removed and the surfaces regained the expected corrosion resistance. KW - Abrasive belt KW - Austenitic stainless steel KW - Electrochemical potentiodynamic reactivation KW - Grinding KW - KorroPad KW - Surface KW - Corrosion PY - 2019 DO - https://doi.org/10.1002/maco.201910874 SN - 0947-5117 SN - 1521-4176 VL - 70 IS - 10 SP - 1776 EP - 1787 PB - Wiley-VCH Verlag CY - Weinheim AN - OPUS4-47871 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ebell, Gino A1 - Burkert, Andreas A1 - Mietz, Jürgen T1 - Detection of reinforcement corrosion in reinforced concrete structures by potential mapping: Theory and practice N2 - Electrochemical potential mapping according to guideline B3 of DGZfP (German Society for Nondestructive Testing) is a recognized technique for the localization of corroding reinforcing steels. In reinforced concrete structures the measured potentials are not necessarily directly linked to the corrosion likelihood of the reinforcing steel. The measured values may be significantly affected, different from, e.g., stress measurement, by different influences on the potential formation at the phase boundary metal/concrete itself as well as the acquisition procedure. Due to the complexity of influencing factors there is a risk that the results are misinterpreted. Therefore, in a training concept firstly the theoretical basics of the test method should be imparted. Then, frequently occurring practical situations of various influencing factors will be made accessible to the participants by a model object specially designed for this purpose. The aim is to impart profound knowledge concerning the characteristics of potential mapping for detecting corrosion of reinforcing steel in order to apply this technique in practice as reliable and economical test method. KW - Corrosion KW - Potential mapping KW - Korrosion KW - Potentialfeldmessung PY - 2018 DO - https://doi.org/10.1155/2018/3027825 SN - 1687-9333 SN - 1687-9325 VL - 2018 SP - Article 3027825, 1 EP - 6 PB - Hindawi AN - OPUS4-46206 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Burkert, Andreas A1 - Müller, Thoralf A1 - Lehmann, Jens A1 - Mietz, Jürgen T1 - Long-term corrosion behaviour of stainless steels in marine atmosphere N2 - Nine different stainless steel alloys were exposed for 5 years under marine environment and their corrosion behaviour was compared and assessed. The investigation of four different surface finishes for all alloys tested further enabled to consider industry-specific features of the surface finish for the material comparison. The results of the exposure tests yield conclusions regarding the influence of alloy composition, surface finish and exposure duration under marine environment. The three duplex stainless steels revealed excellent corrosion resistance even in case of crevices during the 5 years of exposure under the given exposure conditions. Also the molybdenum-alloyed ferritic steel 1.4521 showed good corrosion resistance comparable to the classical austenitic materials 1.4301 and 1.4404. KW - Corrosion KW - Free weathering KW - Marine atmosphere KW - Stainless steels PY - 2018 DO - https://doi.org/10.1002/maco.201709636 SN - 0947-5117 SN - 1521-4176 VL - 69 IS - 1 SP - 20 EP - 28 PB - Wiley-VCH Verlag GmbH & Co KGaA CY - Weinheim AN - OPUS4-43625 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ebell, Gino A1 - Burkert, Andreas A1 - Fischer, Joachim A1 - Lehmann, Jens A1 - Müller, Thoralf A1 - Meinel, Dietmar A1 - Paetsch, O. T1 - Investigation of chloride-induced pitting corrosion of steel in concrete with innovative methods N2 - The combination of electrochemical and 3D computed tomography (CT) investigations offers the possibility of verifying electrochemical measurements non-destructively. Determining the steel surfaces damaged by pitting corrosion allows developing specimens having damage pattern corresponding to practice. Corrosion phenomena like decoupled pitting corrosion cannot be verified by electrochemical measurements only, but with the combination of those two kinds of investigations it is possible. Another advantage is the minimization of the number of samples. The classical experimental procedure requires the destruction of samples after each damage step.This can be avoided by the use of 3D computed tomography. As long as the corrosion phenomena are completely within the examination zone shown by the 3D computed tomography, the electrochemical measurements can be calculated on an area basis to get the specific corrosion rate or polarization resistance. KW - Corrosion KW - Concrete KW - 3D x-ray KW - Corrosion rate PY - 2016 DO - https://doi.org/10.1002/maco.201608969 SN - 1521-4176 SN - 0947-5117 SN - 0043-2822 VL - 67 IS - 6 SP - 583 EP - 590 PB - Wiley-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-36341 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Klapper, Helmuth Sarmiento A1 - Burkert, Andreas A1 - Burkert, Annette A1 - Lehmann, Jens A1 - Villalba, A.L. T1 - Influence of surface treatments on the pitting corrosion of type 304 stainless steel by electrochemical noise measurements N2 - Surface treatments usually are used to modify the appearance and properties of stainless steel surfaces. Simultaneously, the corrosion resistance of the stainless steel surface being related intrinsically to the spontaneous formation of a passive layer also will be affected. In this respect, the influence of different surface treatments on the corrosion resistance of Type 304 (UNS S30400) stainless steel to pitting corrosion has been evaluated by means of potentiostatic electrochemical noise measurements and surface characterization. Typical industrial treatments including mechanical grinding, glass blasting, and pickling were taken into account. Additionally, special consideration was put on the effect of aging conditions of the passive layer after surface treatments, in particular on the relative humidity. Benefits and limitations of the different applied surface treatments concerning protectiveness of the stainless steel surface were determined and discussed. KW - Corrosion KW - Electrochemical noise KW - Pitting corrosion KW - Stainless steel KW - Surface treatment PY - 2011 DO - https://doi.org/10.5006/1.3613641 SN - 0010-9312 SN - 1938-159X VL - 67 SP - 075004-1 EP - 075004-13 PB - National Association of Corrosion Engineers CY - Houston, Tex. AN - OPUS4-24247 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -