TY - JOUR A1 - Pfennig, A. A1 - Kranzmann, Axel T1 - Corrosion and Fatigue of Heat Treated Martensitic Stainless Steel 1.4542 used for Geothermal Applications JF - MATTER - International Journal of Science and Technology N2 - During capture and storage technology (CCS) as well as in geothermal energy production Steels need to withstand the corrosive environment such as: heat, pressure, salinity of the aquifer and CO2-partial pressure. 1.4542 shows unusual corrosion phenomena, but is still sufficiently resistant in corrosive environments. To better understand its behaviour differently heat treated coupons of 1.4542 and for comparison X20Cr13 and X46Cr13 were kept in the artificial brine of the Northern German Basin at T=60 °C. Ambient pressure as well as p=100 bar for 700 h - 8000 h in water saturated supercritical CO2 and CO2-saturated synthetic aquifer Environment was applied. Fatigue tests were performed via push-pull tests with a series of 30 specimens from 150 MPa to 500 MPa (sinusoidal dynamic test loads, R=-1; resonant frequency ~ 30 Hz). FeCO3 and FeOOH are corrosion products also after dynamic corrosion tests. Martensitic microstructure offers good corrosion resistance in geothermal environment. The S-N-curve showing no typical fatigue strength and very steep slopes of possible fatigue strength for finite life. Possible influencing artefacts, such as Al-inclusions could not be correlated to early rupture despite specimens containing inclusions at the fracture surface and cross section reached lower number of cycles. Applied potential proofed to enhance fatigue life tremendously. KW - High Alloyed Steel KW - Pitting KW - Corrosion Fatigue KW - Corrosion KW - Endurance Limit PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503765 DO - https://doi.org/10.20319/mijst.2019.51.138158 SN - 2454-5880 VL - 5 IS - 1 SP - 138 EP - 158 PB - Global Research and Development Services Publishing CY - Rajasthan, India AN - OPUS4-50376 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pfennig, A. A1 - Wolf, M. A1 - Kranzmann, Axel T1 - The role of surface texture on the corrosion fatigue behavior of high alloyed stainless steel exposed to saline aquifer water environment JF - International journal of materials science and engineering N2 - Corrosion fatigue specimen with different surfaces (technical surfaces after machining and polished surfaces) of high alloyed martensitic stainless steel X46Cr13 (1.4043) and duplex stai nless steel X2CrNiMoN22 3 2 (1.4462) were compared at load amplitudes from 175 MPa to 325 MPa in the geothermal brine of the N orthern German Basin at 98 °C. Surface corrosion layers and pits reveal carbonate corrosion products on the surface such as FeCO 3 and FeOOH as the main precipitation phases with no dependence on the original surface roughness . At high stress amplitudes above 275 MPa technical surfaces (P50% at σa 300 MPa=5 × 10 5 ) resulted in more cycles to failure than polished (P50% at σa 300 MPa=1.5 × 10 5 ). The greater slope coefficient for technical surfaces k = 19.006 compared to polished surfaces k =8.78 demonstrate s earlier failure at given stress amplitude σa . KW - Corrosion KW - CCS KW - Carbon storage KW - Aquifer KW - Heat treatment PY - 2019 DO - https://doi.org/10.17706/ijmse SN - 2315-4527 VL - 7 IS - 2 SP - 26 EP - 33 PB - IAP - International Academy Publishing CY - San Bernardino, CA AN - OPUS4-50365 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nolze, Gert A1 - Heide, K. T1 - Roaldite in the iron-meteorite São Julião de Moreira JF - Geochemistry N2 - Roaldite – Fe4N – has been identified in the São Julião de Moreira iron meteorite using electron backscatter diffraction (EBSD) and simultaneously acquired energy-dispersive x-ray spectroscopy (EDS). Mean-periodic-number images derived from raw EBSD patterns confirm this phase by an even higher spatial resolution compared to EDS. Roaldite appears in the form of systematically and repetitively aligned plates. Despite the locally heavy plastic deformation, it is shown that the origin of the oriented precipitation of roaldite is linked to the orientation of the kamacite matrix. Roaldite can be considered to be precipitated from kamacite using an inverse Kurdjumov-Sachs (K-S) or Nishiyama-Wassermann (N-W) orientation relationship. A more accurate discrimination is impossible due to the accumulated shock deformation, which blurs the local reference orientation of kamacite. The habit plane of roaldite is found to be {112}R, which is most likely parallel to {120}K of kamacite. Some of the roaldite plates contain two orientation variants which repeatedly alternate. Their misorientation angle is about 12°. KW - Plastic deformation KW - Iron meteorite KW - Corrosion KW - Nitride KW - Orientation relationship PY - 2019 DO - https://doi.org/10.1016/j.chemer.2019.125538 VL - 79 IS - 4 SP - 125538 PB - Elsevier AN - OPUS4-50338 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Strangfeld, Christoph A1 - Johann, Sergej A1 - Bartholmai, Matthias T1 - Smart RFID Sensors Embedded in Building Structures for Early Damage Detection and Long-Term Monitoring JF - Sensors N2 - In civil engineering, many structures are made of reinforced concrete. Most Degradation processes relevant to this material, e.g., corrosion, are related to an increased level of material moisture. Therefore, moisture monitoring in reinforced concrete is regarded as a crucial method for structural health monitoring. In this study, passive radio frequency identification (RFID)-based sensors are embedded into the concrete. They are well suited for long-term operation over decades and are well protected against harsh environmental conditions. The energy supply and the data transfer of the humidity sensors are provided by RFID. The sensor casing materials are optimised to withstand the high alkaline environment in concrete, having pH values of more than 12. Membrane materials are also investigated to identify materials capable of enabling water vapour transport from the porous cement matrix to the embedded humidity sensor. By measuring the corresponding relative humidity with embedded passive RFID-based sensors, the cement hydration is monitored for 170 days. Moreover, long-term moisture monitoring is performed for more than 1000 days. The Experiments show that embedded passive RFID-based sensors are highly suitable for long-term structural health monitoring in civil engineering. KW - RFID based sensors KW - Embedded sensors KW - Corresponding relative humidity KW - Porous building materials KW - Reinforced concrete KW - Corrosion KW - Civil engineering PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-500831 DO - https://doi.org/10.3390/s19245514 VL - 19 IS - 24 SP - 1 EP - 18 PB - MDPI CY - Basel, Swiss AN - OPUS4-50083 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Aristia, Gabriela A1 - Le, Quynh Hoa A1 - Bäßler, Ralph T1 - Corrosion of Carbon Steel in Artificial Geothermal Brine: Influence of Carbon Dioxide at 70 °C and 150 °C JF - Materials N2 - This study focuses on the corrosion mechanism of carbon steel exposed to an artificial geothermal brine influenced by carbon dioxide (CO2) gas. The tested brine simulates a geothermal source in Sibayak, Indonesia, containing 1500 mg/L of Cl-, 20 mg/L of SO4 2-, and 15 mg/L of HCO3-with pH 4. To reveal the temperature effect on the corrosion behavior of carbon steel, exposure and electrochemical tests were carried out at 70 °C and 150 °C. Surface analysis of corroded specimens showed localized corrosion at both temperatures, despite the formation of corrosion products on the surface. After 7 days at 150 °C, SEM images showed the formation of an adherent, dense, and crystalline FeCO3 layer. Whereas at 70 °C, the corrosion products consisted of chukanovite (Fe2(OH)2CO3) and siderite (FeCO3), which are less dense and less protective than that at 150 °C. Control experiments under Ar-environment were used to investigate the corrosive effect of CO2. Free corrosion potential (Ecorr) and electrochemical impedance spectroscopy (EIS) confirm that at both temperatures, the corrosive effect of CO2 was more significant compared to that measured in the Ar-containing solution. In terms of temperature effect, carbon steel remained active at 70 °C, while at 150 °C, it became passive due to the FeCO3 formation. These results suggest that carbon steel is more susceptible to corrosion at the near ground surface of a geothermal well, whereas at a deeper well with a higher temperature, there is a possible risk of scaling (FeCO3 layer). A longer exposure test at 150 °C with a stagnant solution for 28 days, however, showed the unstable FeCO3 layer and therefore a deeper localized corrosion compared to that of seven-day exposed specimens. KW - Carbon steel KW - CO2 KW - Corrosion KW - Electrochemical impedance spectroscopy KW - Geothermal PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498168 DO - https://doi.org/10.3390/ma12223801 SN - 1996-1944 VL - 12 IS - 22 SP - 3801-1 EP - 20 PB - MDPI CY - Basel AN - OPUS4-49816 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Seneschal-Merz, Karine A1 - Bücker, Michael A1 - Feldmann, Ines T1 - Low melting glasses for transparent and environmentally-resistant enamels JF - Glass Technology: European Journal of Glass Science and Technology Part A N2 - Today glass is broadly used in modern architecture. For indoor applications it is possible to produce decorated glass by using enamel colours and glass painting techniques without any problems. However, this is more limited for applications out of doors. Humidity and environmental pollution attack the surface of the coating and can damage it. There are only a few colours on the market which are resistant towards acids and bases until now. Additionally, most of those colours are opaque. To extend the colour palette, chemically resistant low melting coloured glasses are being developed which are transparent and intensively toned even in thin coating thicknesses. To achieve such an ambitious aim, many parameters have to combine and act in a complex manner. New compositions of lead borosilicate, zinc borosilicate and lead-zinc borosilicate glasses were produced and milled as powder. The thermal properties as well as the environmental stability were analysed. The influence of PbO and ZnO on the thermal properties and the environmental stability were investigated. Evaluation of the fusing results shows that the production and mixture of transparent vitreous enamels for the exterior side of glasses is possible. The tests made it clear that the original materials for making the vitreous enamels must be excellently ground and prepared to achieve a satisfactory result. The method to produce durable vitreous enamels for exterior application also seems to allow the production of glass colours. KW - Low melting glasses KW - Enamels KW - Heavy metal free KW - Corrosion KW - Chemical durability KW - Aging tests KW - Architecture KW - Colored glasses PY - 2019 DO - https://doi.org/10.13036/17533546.60.4.002 SN - 1753-3546 SN - 1753-3554 VL - 60 IS - 4 SP - 97 EP - 104 PB - Society of Glass Technology CY - Sheffield, UK AN - OPUS4-48835 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Völker, Christoph A1 - Kruschwitz, Sabine A1 - Ebell, Gino T1 - A machine learning‑based data fusion approach for improved corrosion testing JF - Surveys in Geophysics N2 - This work presents machine learning-inspired data fusion approaches to improve the non-destructive testing of reinforced concrete. The principal effects that are used for data fusion are shown theoretically. Their effectiveness is tested in case studies carried out on largescale concrete specimens with built-in chloride-induced rebar corrosion. The dataset consists of half-cell potential mapping, Wenner resistivity, microwave moisture and ground penetrating radar measurements. Data fusion is based on the logistic Regression algorithm. It learns an optimal linear decision boundary from multivariate labeled training data, to separate intact and defect areas. The training data are generated in an experiment that simulates the entire life cycle of chloride-exposed concrete building parts. The unique possibility to monitor the deterioration, and targeted corrosion initiation, allows data labeling. The results exhibit an improved sensitivity of the data fusion with logistic regression compared to the best individual method half-cell potential. KW - Corrosion KW - Potential mapping KW - Machine learning PY - 2019 DO - https://doi.org/10.1007/s10712-019-09558-4 SN - 1573-0956 SN - 0169-3298 VL - 41 IS - 3 SP - 531 EP - 548 PB - Springer Nature AN - OPUS4-48799 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Aristia, Gabriela A1 - Le, Quynh Hoa A1 - Bäßler, Ralph T1 - Electrochemical deposition of polyaniline on carbon steel for corrosion study in geothermal solution JF - Materials Science Forum N2 - Polyaniline has been widely developed for many applications, e.g. sensor, supercapacitor components, electrochromic devices, and anticorrosion pigments. Although the addition of polyaniline pigment in organic coatings has been an alternative for corrosion protection in industrial applications, the protection mechanism is still not fully understood. Herein in this study, as a part of the development of polyaniline/silicon dioxide coating for geothermal application, polyaniline has been deposited electrochemically on carbon steel surface in oxalic acid medium and tested in geothermal solution to understand the contribution of polyaniline to the corrosion protection of a polyaniline-based composite in the geothermal system. To observe the surface/interface reaction between the electrolyte and electrode surface during the electrochemical polymerization, electrochemical impedance spectroscopy (EIS) was applied after each cycle. For corrosion study in the geothermal application, an artificial geothermal solution was used with the composition of 1,500 mg/l Cl⁻, 20 mg/l SO₄²⁻, 15 mg/l HCO₃⁻, 200 mg/l Ca²⁺, 250 mg/l K⁺, and 600 mg/l Na⁺, and pH 4 to simulate a geothermal brine found in Sibayak, Indonesia. An electrochemical measurement was performed by monitoring the open circuit potential over seven days, with the interruption by EIS every 22 hours. The experiments were performed at room temperature and 150 °C (1 MPa) in an oxygen-free environment. Impedance spectra showed a reduction of the total impedance value of approximately 10 times for specimens measured at 150 °C compared to the specimens measured at room temperature, suggesting a less stable layer at high temperature. KW - Corrosion KW - Electrochemical deposition KW - Polyaniline PY - 2019 DO - https://doi.org/10.4028/www.scientific.net/MSF.966.107 SN - 1662-9752 VL - 966 SP - 107 EP - 115 PB - Trans Tech Publications Ltd CY - Zürich AN - OPUS4-48776 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Faes, W. A1 - Lecompte, S. A1 - van Bael, J. A1 - Salenbien, R. A1 - Bäßler, Ralph A1 - Bellemans, I. A1 - Cools, P. A1 - de Geyter, N. A1 - Morent, R. A1 - Verbeken, K. A1 - de Paepe, M. T1 - Corrosion behaviour of different steel types in artificial geothermal fluids JF - Geothermics N2 - Geothermal energy is an interesting alternative to polluting fossil energy sources. Therefore, in Belgium, two wells have been drilled for a deep geothermal power plant. However, the environment to which the installations are exposed is challenging. The geothermal brine has 165 g/l total dissolved solids (of which 90% are sodium and chlorine) and the production temperature can be up to 130 °C. To assess their suitability to be used in a geothermal power plant, the corrosivity of the artificial brine to three common construction materials was investigated with exposure and electrochemical tests. The metals under consideration are a low-alloyed carbon steel (S235JR), an austenitic stainless steel (UNS S31603) and a duplex stainless steel (UNS S31803). The carbon steel, that was found to corrode uniformly, could be considered as a constructional material if a sufficient wall thickness is chosen. The austenitic stainless steel and the duplex stainless steel demonstrate very low uniform corrosion rates. They are however susceptible to pitting and crevice corrosion. To guarantee safe operation of the geothermal power plant, the susceptibility of the alloys to stress corrosion cracking should be tested and in situ experiments should be performed. KW - Geothermal energy KW - Corrosion KW - Carbon dioxide KW - Carbon steel KW - Stainless steel PY - 2019 DO - https://doi.org/10.1016/j.geothermics.2019.05.018 SN - 0375-6505 VL - 82 IS - 11 SP - 182 EP - 189 PB - Elsevier Ltd. AN - OPUS4-48759 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Munasir, A1 - Triwikantoro, A1 - Zainuri, M. A1 - Bäßler, Ralph A1 - Darminto, T1 - Corrosion Polarization Behavior of Al-SiO2 Composites in 1M NaCl and Related Microstructural Analysis JF - International Journal of Engineering N2 - The composites combining aluminum and silica nanoparticles with the addition of tetramethylammonium hydroxide (Al-SiO2(T)) and butanol (Al-SiO2(B)) as mixing media have been successfully fabricated. Corrosion behavior of Al-SiO2 composites before and after exposure in 1M NaCl solution was examined using potentiodynamic polarization (Tafel curve analysis). The study was also equipped with scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and X-ray diffraction (XRD) investigations. Before exposure, Al-SiO2(T) exhibited the best corrosion resistance. Performance improvement was indicated by Al-SiO2(B) up to 10 times better than Al-SiO2(T) after exposure. The increased SiO2 content did not significantly enhance the corrosion resistance of the composites. The Al-SiO2 composites with 5% SiO2 content showed very high corrosion resistance (as the optimum composition). Furthermore, pitting corrosion was observed in the Al-SiO2 composites, indicated by the formation of corrosion products at grain boundaries. The product was affected by the presence of SiO2 in the Al matrix and the NaCl environment at 90 °C (approach to synthetic geothermal media: Na+, Cl, H+, OH-). Our study revealed the presence of γ-Al2O3, γ-Al(OH)3, and Al(OH)2Cl as the dominant corrosion products. KW - Al-Composite KW - Corrosion KW - Corrosion rate KW - SiO2 Nanoparticle KW - Tafel Plot PY - 2019 DO - https://doi.org/10.5829/ije.2019.32.07a.11 SN - 1025-2495 SN - 1735-9244 VL - 7 IS - 32 SP - 982 EP - 990 PB - Materials and Energy Research Center AN - OPUS4-48742 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -