TY - JOUR A1 - Haller, T. A1 - Völker, Christoph A1 - Hartmann, T. T1 - Machine learning based multi-sensor fusion for the nondestructive testing of corrosion in concrete N2 - Half-cell potential mapping (HP) is the most popular non-destructive testing method (NDT) for locating corrosion damage in concrete. It is generally accepted that HP is susceptible to environmental factors caused by salt-related deterioration, such as different moisture and chloride gradients. Additional NDT methods are able to identify distinctive areas but are not yet used to estimate more accurate test results. We present a Supervised Machine Learning (SML) based approach to data fusion of seven different signal features to obtain higher quality information. SMLs are methods that explore (or learn) relationships between different (sensor) data from predefined data labels. To obtain a representative, labelled data set we conducted a comprehensive experiment simulating the deterioration cycle of a chloride exposed device in the laboratory. Our data set consists of 18 measurement campaigns, each containing HP, Ground Penetrating- Radar, Microwave Moisture and Wenner resistivity data. We compare the performance of different ML approaches. Many outperform the best single method, HP. We describe the intrinsic challenges posed by a data-driven approach in NDT and show how future work can help overcome them. T2 - SMAR2019 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures CY - Potsdam, Germany DA - 27.08.2019 KW - Machine Learning KW - NDT KW - Half-Cell Potential Mapping KW - Corrosion KW - Reinforced Concrete KW - Data Fusion PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498563 UR - http://www.ndt.net/?id=24890 VL - 25 IS - 1 SP - 24890-1 EP - 24890-8 PB - NDT.net CY - Kirchwald AN - OPUS4-49856 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pfennig, Anja A1 - Wolf, Marcus A1 - Kranzmann, Axel T1 - Corrosion and corrosion fatigue of steels in downhole CCS environment - A summary N2 - Static immersion tests of potential injection pipe steels 42CrMo4, X20Cr13, X46Cr13, X35CrMo4, and X5CrNiCuNb16-4 at T = 60 °C and ambient pressure, as well as p = 100 bar were performed for 700–8000 h in a CO₂-saturated synthetic aquifer environment similar to CCS sites in the Northern German Basin (NGB). Corrosion rates at 100 bar are generally lower than at ambient pressure. The main corrosion products are FeCO₃ and FeOOH with surface and local corrosion phenomena directly related to the alloy composition and microstructure. The appropriate heat treatment enhances corrosion resistance. The lifetime reduction of X46Cr13, X5CrNiCuNb16-4, and duplex stainless steel X2CrNiMoN22-5-3 in a CCS environment is demonstrated in the in situ corrosion fatigue CF experiments (axial push-pull and rotation bending load, 60 °C, brine: Stuttgart Aquifer and NGB, flowing CO₂: 30 L/h, +/- applied potential). Insulating the test setup is necessary to gain reliable data. S-N plots, micrographic-, phase-, fractographic-, and surface analysis prove that the life expectancy of X2CrNiMoN22-5-3 in the axial cyclic load to failure is clearly related to the surface finish, applied stress amplitude, and stress mode. The horizontal grain attack within corrosion pit cavities, multiple fatigue cracks, and preferable deterioration of austenitic phase mainly cause fatigue failure. The CF life range increases significantly when a protective potential is applied. KW - Steel KW - High alloyed steel KW - Corrosion KW - Corrosion fatigue KW - Carbon capture and storage PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531391 DO - https://doi.org/10.3390/pr9040594 SN - 2227-9717 VL - 9 IS - 4 SP - 1 EP - 33 PB - MDPI CY - Basel AN - OPUS4-53139 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pfennig, A. A1 - Kranzmann, Axel T1 - Understanding the Anomalous Corrosion Behaviour of 17% Chromium Martensitic Stainless Steel in Laboratory CCS-Environment—A Descriptive Approach N2 - To mitigate carbon dioxide emissions CO2 is compressed and sequestrated into deep geological layers (Carbon Capture and Storage CCS). The corrosion of injection pipe steels is induced when the metal is in contact with CO2 and at the same time the geological saline formation water. Stainless steels X35CrMo17 and X5CrNiCuNb16-4 with approximately 17% Cr show potential as injection pipes to engineer the Northern German Basin geological onshore CCS-site. Static laboratory experiments (T = 60 ◦C, p = 100 bar, 700–8000 h exposure time, aquifer water, CO2-flow rate of 9 L/h) were conducted to evaluate corrosion kinetics. The anomalous surface corrosion phenomena were found to be independent of heat treatment prior to exposure. The corrosion process is described as a function of the atmosphere and diffusion process of ionic species to explain the precipitation mechanism and better estimate the reliability of these particular steels in a downhole CCS environment. KW - Corrosion KW - Steel KW - High alloyed steel KW - Corrosion mechanism KW - CCS PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545700 DO - https://doi.org/10.3390/cleantechnol4020014 VL - 4 IS - 2 SP - 239 EP - 257 PB - MDPI AN - OPUS4-54570 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Matamoros-Veloza, A. A1 - Stawski, Tomasz A1 - Vargas, S. A1 - Neville, A. T1 - Study of a Local Structure at the Interface between Corrosion Films and Carbon Steel Surface in Undersaturated CO2 Environments N2 - Industries transporting CO2 gas-saturated fluids have infrastructures made of carbon steel. This is a good material with great mechanical properties but prone to corrosion and potential failure. Corrosion in sweet environments involves the formation of FeCO3 as a corrosion film, which is recognized to play a protective role under certain conditions. This work on the dissolution of corrosion films in sweet environments, under acidic and undersaturated conditions, demonstrates that the effects on the integrity of steel are far more significant than the damage observed on the surface of the corrosion film. Our results prove that dissolution of FeCO3 involved the presence of an amorphous phase, the intermediate formation of FeCl2 or FeCl+, and the presence of a phase with short distance atom–atom correlations. The amorphous phase was identified as a mixture of retained γ-Fe and Fe3C. Partially broken α-Fe and Fe3C structures were identified to prove the damage on the material, confirming the interface zone without evident damage on the corrosion film. Dissolution affected both the α-Fe and FeCO3, with the lattice [102̅] from the FeCO3 crystalline structure being the fastest to dissolve. The damage of steel at the molecular scale was evident at the macroscale with pit depths of up to 250 μm. The impact on the integrity of steel can be, therefore, more drastic than frequently reported in industrial operations of CO2 transport industries that use cleaning procedures (e.g., acid treatment, pigging) as part of their operational activities. KW - Steel KW - Corrosion KW - Siderite KW - Diffraction KW - Pair distribution function KW - Synchrotron PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572156 DO - https://doi.org/10.1021/acsomega.2c07631 SN - 2470-1343 VL - 8 IS - 9 SP - 8497 EP - 8504 PB - ACS AN - OPUS4-57215 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bulling, Jannis A1 - Jurgelucks, B. A1 - Prager, Jens A1 - Walther, A. T1 - Defect reconstruction in a two-dimensional semi-analytical waveguide model via derivative-based optimization N2 - This paper considers an indirect measurement approach to reconstruct a defect in a two-dimensional waveguide model for a non-destructive ultrasonic inspection via derivative-based optimization. The propagation of the mechanical waves is simulated by the scaled boundary finite element method that builds on a semi-analytical approach. The simulated data are then fitted to given data associated with the reflected waves from a defect which is to be reconstructed. For this purpose, we apply an iteratively regularized Gauss-Newton method in combination with algorithmic differentiation to provide the required derivative information accurately and efficiently. We present numerical results for three kinds of defects, namely, a crack, delamination, and corrosion. The objective function and the properties of the reconstruction method are investigated. The examples show that the parameterization of the defect can be reconstructed efficiently as well as robustly in the presence of noise. KW - Mechanical waves KW - Corrosion KW - Finite-element analysis KW - Ultrasonic testing KW - Nondestructive testing techniques KW - Symbolic computation KW - Materials analysis KW - MATLAB KW - Newton Raphson method PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565485 DO - https://doi.org/10.1121/10.0013574 VL - 152 IS - 2 SP - 1217 EP - 1229 PB - AIP Publ. CY - Melville, NY AN - OPUS4-56548 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kauss, N. A1 - Rosemann, Paul A1 - Halle, T. T1 - Age-hardening behaviour, microstructure and corrosion resistance of the copper alloyed stainless steel 1.4542 N2 - The copper alloyed stainless steel 1.4542 (X5CrNiCuNb16-4) is used in different areas due to its good mechanical properties and corrosion resistance. Strength and corrosion resistance can be adjusted by the heat treatment, which is of importance for the application of this alloy. The mechanical properties (strength and hardness) are attributed to the dispersive precipitation of the copper rich ε–Phase. The additional precipitation of chromium carbides can reduce the corrosion resistance. Different ageing states were produced to investigate the precipitation behaviour with various methods. Furthermore, the influence of cold-rolling on the precipitation behaviour was studied in comparison to a solution annealed state without deformation. The microstructure was studied by SEM and the variations of hardness and magnetic proportion were characterised. The electrochemical potentiodynamic reactivation (EPR) was used to determine the corrosion resistance and detect chromium depletion in all heattreated states. The results show that a work hardening accelerates the precipitation rate, while ageing at 600 °C reduces the corrosion resistance due to chromium depletion. T2 - WTK2018 CY - Chemnitz DA - 14.03.2018 KW - Corrosion KW - Corrosion resistance KW - Corrosion testing KW - EPR KW - Heat treatment KW - Stainless steel PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-452482 DO - https://doi.org/10.1088/1757-899X/373/1/012020 SN - 1757-899X SN - 1757-8981 VL - 373 SP - Article 012020, 1 EP - 9 PB - Institute of Physics CY - London AN - OPUS4-45248 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 - Pfennig, Anja A1 - Wolf, M. A1 - Kranzmann, Axel T1 - Corrosion and Corrosion Fatigue of Steels in Downhole CCS Environment—A Summary N2 - Static immersion tests of potential injection pipe steels 42CrMo4, X20Cr13, X46Cr13, X35CrMo4, and X5CrNiCuNb16-4 at T = 60°C and ambient pressure, as well as p = 100 bar were performed for 700–8000 h in a CO2-saturated synthetic aquifer environment similar to CCS sites in the Northern German Basin (NGB). Corrosion rates at 100 bar are generally lower than at ambient pressure. The main corrosion products are FeCO3 and FeOOH with surface and local corrosion phenomena directly related to the alloy composition and microstructure. The appropriate heat treatment enhances corrosion resistance. The lifetime reduction of X46Cr13, X5CrNiCuNb16-4, and duplex stainless steel X2CrNiMoN22-5-3 in a CCS environment is demonstrated in the in situ corrosion fatigue CF experiments (axial push-pull and rotation bending load, 60°C , brine: Stuttgart Aquifer and NGB, flowing CO2: 30 L/h, +/- applied potential). Insulating the test setup is necessary to gain reliable data. S-N plots, micrographic-, phase-, fractographic-, and surface analysis prove that the life expectancy of X2CrNiMoN22-5-3 in the axial cyclic load to failure is clearly related to the surface finish, applied stress amplitude, and stress mode. The horizontal grain attack within corrosion pit cavities, multiple fatigue cracks, and preferable deterioration of austenitic phase mainly cause fatigue failure. The CF life range increases significantly when a protective potential is applied. KW - Carbon capture and storage KW - Steel KW - High alloyed steel KW - Corrosion KW - Corrosion fatigue KW - CCS PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523948 DO - https://doi.org/10.3390/pr9040594 VL - 9 IS - 4 SP - 594 PB - MDPI CY - Basel, Switzerland AN - OPUS4-52394 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Babutzka, Martin A1 - Grabowski, Sven A1 - Sahrhage, H. A1 - Lampke, T. T1 - Electrochemical corrosion investigations on binary and ternary zinc alloy coatings using gel electrolytes N2 - Novel agar-based test electrolytes are used to perform electrochemical corrosion investigations on ZnFe and ZnNi binary as well as ZnFeMo ternary zinc coatings. The objectives of the electrochemical investigations include the characterization of the corrosion behavior, the description of the protective effect of the coatings as well as the investigation of the layer formation and degradation under artificial aging. ZnFe and ZnFeMo coatings are applied with varying iron content as well as an additional passivation layer, respectively, to study the effect on corrosion resistance. The results show that the protective effect of the coatings is not negatively influenced by different iron contents or the addition of molybdenum. Additional passivation of the ZnFe-containing coatings by means of a passivating agent leads to a significant improvement in the protective effect. Artificial aging leads to slight degradation of the additional passivation layer whereas coatings without post-treatment enhance their protective effect by the formation of corrosion product layers. KW - Binary zinc alloys KW - Ternary zinc alloys KW - Corrosion testing KW - Gel electrolytes KW - Corrosion PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543013 DO - https://doi.org/10.1002/adem.202101336 SN - 1438-1656 SP - 1 EP - 14 PB - Wiley-VCH CY - Weinheim AN - OPUS4-54301 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 -