TY - CONF A1 - Rosemann, Paul A1 - Müller, C. A1 - Kauss, N. A1 - Halle, T. T1 - Application of the electrochemical potentiodynamic reactivation method on martensitic stainless steels N2 - The double loop electrochemical potentiodynamic reactivation (EPR) method is a standardised procedure for detecting and quantifying sensitisation on austenitic, ferritic and ferritic-austenitic stainless-steel grades. This sensitisation is caused by microstructural alternations, as the formation of chromium carbides, nitrides or sigma-phases, which generate local chromium depleted zones nearby. The latter strongly influence the corrosion resistance and the electrochemical response of a stainless steel during electrochemical potentiodynamic reactivation, providing important information on the degree of chromium depletion. In case of martensitic stainless steels, which are used for cutlery and surgical instruments, the heat treatment has a strong impact on the microstructure, the material properties and especially on the corrosion resistance. To study this interaction, the EPR method was modified for the application on martensitic stainless steels with about 13 wt.-% chromium. Different H2SO4 concentrations and EPR-parameters were tested and compared on two standard martensitic stainless-steel grades (AISI 420 A / X20Cr13 and AISI 420 C / X46Cr13) to define applicable parameters. Afterwards, these parameters were used to study the effect of austenitisation time and cooling rate on the corrosion resistance of both martensitic stainless steels. The response of both alloys was different due to the different carbon levels, which will be explained by microstructural investigations in detail. All results allow postulating a process window, in which chromium depletion is suppressed and an optimised corrosion resistance is guaranteed. Based on this research, the modified EPR-test is now used to control the heat treatment and its impact on the corrosion resistance of martensitic stainless steels in the cutlery industry. The EPR-test is thus an interesting alternative for manufacturers, processors, users and researchers to the time-consuming exposition test normally used to characterise the corrosion resistance of martensitic stainless steels. T2 - Electrochemical Methods in Corrosion Research 2018 CY - Cambridge, UK DA - 22.07.2018 KW - EPR KW - Corrosion resistance KW - Heat treatment KW - Stainless steels KW - Corrosion KW - Corrosion testing KW - Martensitic stainless steels PY - 2018 AN - OPUS4-45613 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Aristia, Gabriela A1 - Bäßler, Ralph A1 - Roth, C. T1 - Polyaniline/silicon dioxide containing coating for use in artificial geothermal brines N2 - Geothermal brine is a complex system containing a wide variety of dissolved salts resulting from the condition s in a geothermal well. These fluids lead to corrosion in pipes and other parts of geothermal system construction and necessitate intense research efforts in finding new suitable materials. Carbon steel is susceptible to corrosion in geothermal brine especially when it is exposed to a high temperature and high-pressure medium, which is considered to be an aggressive environment. An artificial geothermal water, bas ed on a brine composition found in Indonesia, was used to investigate the performance of high alloyed materials. The electrolyte has pH 4 and contains 1,500 mg/l Cl-, 20 mg/l SO4 2-, 15 mg/l HCO3 -, 200 mg/l Ca 2+, 250 mg/l K+, and 600 mg/l Na+. In order to protect the bare material in geothermal application, it is necessary to either use high alloyed material s or coatings. In this research, a coating system consisting of polyaniline and silicon dioxide was investigated regarding its behavior to protect carbon steel. In detail, the effect of SiO2 and polyaniline (PANi) addition was evaluated by exposure and electrochemical tests for 7 days, i.e. electrochemical impedance spectroscopy (EIS) and open circuit potential (OCP) at room temperature and 150 °C with 1 MPa pressure. T2 - NACE International Annual Corrosion Conference CY - Phoenix, AZ, USA DA - 15.04.2018 KW - Geothermal KW - Coating KW - SiO2 KW - Polyaniline KW - Corrosion PY - 2018 AN - OPUS4-44919 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Witt, Julia A1 - Almalla, Ahed A1 - Özcan Sandikcioglu, Özlem T1 - In situ AFM studies of deformation and corrosion processes on AA2024-T3 aluminium alloy N2 - The performance of functional coatings and adhesively joined hybrid components relies strongly on the stability of the polymer-metal interface. With the increasing utilization of multi-material structures in the automotive and aerospace industry, it is of great scientific and technical interest to understand the processes leading to interface degradation and to develop novel strategies to increase corrosion and delamination resistance. The aim of this project is to develop thin epoxy-based films on aluminium alloy AA2024-T3 as a model system and to investigate their interfacial stability under corrosive and coupled corrosive-mechanical load. Electrochemical and spectroscopic methods were used for the characterisation of the film properties and in situ corrosion experiments were performed by means of AFM. The deformation properties of the aluminium alloy and the model coatings were investigated by means of scanning Kelvin probe force microscopy (SKPFM) utilizing the integrated tensile stage. The presentation will give a brief overview of the capabilities of the new AFM setup to foster future collaborations and summarize our work on the interface stability of model coatings. T2 - Abteilungskolloquium FB6 CY - Berlin, Germany DA - 27.11.2018 KW - Corrosion KW - In situ Atomic Force Microscopy (AFM) KW - Aluminium alloy KW - Scanning Kelvin Probe Force Microscopy (SKPFM) PY - 2018 AN - OPUS4-48027 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Özcan Sandikcioglu, Özlem A1 - Wurzler, Nina A1 - Witt, Julia A1 - Dimper, Matthias A1 - Wagner, R. A1 - Lützenkirchen-Hecht, D. T1 - Changes in passive film chemistry of stainless steels in the presence of iron reducing bacteria N2 - Summary of the results obtained at DELTA-Beamline 8 in 2018. T2 - DELTA User Treffen CY - Dortmund, Germany DA - 28.11.2018 KW - MIC KW - Corrosion KW - XANES PY - 2018 AN - OPUS4-50312 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Özcan Sandikcioglu, Özlem A1 - Wurzler, Nina A1 - Hampel, Marco A1 - Witt, Julia A1 - Schenderlein, Matthias T1 - Combined electrochemical techniques for the investigation of corrosion processes N2 - Short presentation of BAM, a summary of the methods available in FB 6.2 and recent results on MIC and high resolution corrosion studies T2 - Institute Seminar: Jerzy Haber Institute of Catalysis and Surface Chemistry CY - Cracow, Poland DA - 07.11.2018 KW - MIC KW - Corrosion KW - Atomic Force Microscopy (AFM) KW - Combined corrosive and mechanical load PY - 2018 AN - OPUS4-50313 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rosemann, Paul A1 - Lehmann, Jens A1 - Burkert, Andreas T1 - Corrosion resistance of ferritic stainless steels studied with various methods on different time scales N2 - The corrosion resistance of stainless-steels grades is of high importance for the technical safety in different environmental conditions. Processing and surface finish influences the corrosion resistance of ferritic stainless steels, which may be considered for some application in marine environment. Three ferritic stainless steel alloys (X2CrNi12, X2CrTiNb18 and X2CrMoTi18-2) were exposed in four different surface finishes (rolled, dry grinding, glass beaded and electro polished) for five years in marine environment to obtain reliable information about the corrosion resistance. All samples were assessed after 22 and 60 months according to DIN EN ISO 10289 in validation degrees from 1 to 10. Complementary investigation using accelerated chamber test (salt spray test followed by four weeks storage at 30 °C / 80 % relative humidity) and short-term electrochemical methods (electrochemical potentiodynamic reactivation, pitting potentials and the KorroPad method) were conducted to compare their results. The presentation gives an overview on all methods and the generated results, which show benefits and restrictions of long-term, accelerated and short-term corrosion tests. T2 - EUROCORR 2018 CY - Krakow, Poland DA - 09.09.2018 KW - Corrosion KW - Stainless steel KW - Corrosion resistance KW - EPR KW - Corrosion testing KW - Pitting corrosion KW - Atmospheric corrosion KW - Surface treatment PY - 2018 AN - OPUS4-45940 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Witt, Julia A1 - Almalla, Ahed A1 - Stepien, Daniel A1 - Özcan Sandikcioglu, Özlem T1 - Multilayer thin coatings for corrosion protection of AA2024-T3 aluminium alloy N2 - The performance of adhesively joined hybrid components relies strongly on the stability of the adhesive-material interface. With the increasing utilization of multi-material structures in the automotive and aerospace industry, it is of great scientific and technical interest to understand the processes leading to adhesive failure and to develop novel strategies to increase corrosion and delamination resistance of adhesive joints. The aim of this study is to develop thin epoxy based films and their carbon nanofiller loaded composites on aluminium alloy AA2024-T3 and to investigate their interfacial stability under corrosive and coupled corrosive-mechanical load. Spin coating was used for the layer-by-layer deposition of poly[(o-cresyl glycidyl ether)-co-formaldehyde] and poly-(ethylenimine) bi-layers. Carbon nanofillers are introduced either by mixing into the coating components or in between individual layers. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analysis was performed to investigate the porosity and water uptake of the model films, respectively. Atomic force microscopy (AFM) results indicated a very homogeneous and dense film with low surface roughness. The bi-layer thickness ranged between 30 to 40 nm. Electrochemical measurements show a higher corrosion resistance with the increase of the bi-layer number. The main novelty of this contribution is the in-situ AFM investigations under coupled corrosive-mechanical load. For this purpose, a tensile module capable of uniaxial stretching and compression with up to 5 kN force was integrated into the AFM stage. Stretching experiments were performed to investigate the mechanical properties and adhesion of the films, as well as structural changes of the film morphology during uniaxial deformation. The contribution will provide detailed information on the new AFM setup and summarize our results on the stability of model epoxy and nanocomposite films on AA2024-T3. T2 - EURADH 2018 CY - Lisbon, Portugal DA - 05.09.2018 KW - Electrochemical Empedance Spectroscopy (EIS) KW - Scanning Kelvin Probe Force Microscopy (SKPFM) KW - Corrosion KW - Delamination KW - Aluminium KW - Epoxide PY - 2018 AN - OPUS4-46513 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rosemann, Paul A1 - Müller, C. A1 - Roßberg, S. A1 - Pensel, P. A1 - Heyn, A. A1 - Burkert, Andreas T1 - Precipitation behavior and corrosion resistance of nickel-free, high-nitrogen austenitic stainless steels N2 - Nickel-free, nitrogen alloyed austenitic stainless-steels, with about 19 wt.-% Mn and 0,8 wt. % N, are an interesting alternative to classic CrNi austenitic stainless steels due to their superior mechanical properties (Rm > 900 MPa, A5 > 50 %, Av > 350 J) in the solution annealed condition. The formation of chromium-rich nitrides during suboptimal heat treatment, processing or application leads to an inhomogeneous distribution of alloying elements in the microstructure, which reduces the corrosion resistance. Consequently, an accurate knowledge of the sensitization behavior is indispensable for the use of nickel-free, high-nitrogen austenitic stainless steels. The relationship between artificial aging, phase formation and corrosion resistance was investigated on the alloys X8CrMnN18-19 (1.3815) and X8CrMnMoN18-19-2 (1.4456), both alloyed with 0,8 wt.-% Nitrogen, in the present work. The microstructural evolution was studied by LM and SEM while the corrosion resistance was characterized with the electrochemical potentiodynamic reactivation (EPR) and the KorroPad indicator-test. Both alloys showed increased corrosion susceptibility within critical aging parameters. Finally, a sensitization diagram was described successfully for both alloys showing the positive effect of molybdenum. T2 - Materials Science and Engineering 2018 (MSE) CY - Darmstadt, Germany DA - 26.09.2018 KW - Corrosion KW - Corrosion resistance KW - Heat treatment KW - KorroPad KW - Nitrogen KW - Pitting corrosion KW - Stainless steel KW - ThermoCalc PY - 2018 AN - OPUS4-46093 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kauss, N. A1 - Halle, T. A1 - Rosemann, Paul T1 - Age-hardening behavior, 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 heat-treated 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 - Materials Science and Engineering 2018 (MSE) CY - Darmstadt, Germany DA - 26.09.2018 KW - Corrosion KW - Corrosion resistance KW - Corrosion testing KW - EPR KW - Heat treatment KW - Martensitic stainless steels KW - REM KW - Stainless steel KW - ThermoCalc PY - 2018 AN - OPUS4-46094 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Babutzka, Martin T1 - Vorstellung des Programms WIPANO sowie aktueller Projektskizzen der BAM im Fachbereich 7.6 N2 - Der Vortrag erläutert die Förderschwerpunkte der Förderinitiative WIPANO des BMWi und zeigt aktuelle Projektskizzen sowie Projekte des Fachbereiches 7.6. T2 - Arbeitskreissitzung „Korrosionsuntersuchung und -überwachung“ des GfKORR e. V. CY - Berlin, Germany DA - 08.10.2018 KW - Korrosion KW - Corrosion KW - Zink KW - Spannstahl KW - KorroPad PY - 2018 AN - OPUS4-46379 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -