TY - CONF A1 - Wurzler, Nina A1 - Özcan Sandikcioglu, Özlem T1 - The effect of flavins on the corrosion properties of stainless steels during initial stages of microbiologically influenced corrosion N2 - Microbiologically influenced corrosion (MIC) on steel occurs where the presence and activity of microbes change the localized conditions on the surface of a metal substrate. For instance, metal reducing bacteria (MRB) are capable of utilizing metal compounds in the passive layer on stainless steel as electron acceptors during their metabolism. This weakening of the passive film not only leads to an acceleration of the general corrosion processes, but also increases the susceptibility of stainless steels to pitting corrosion. Even though the electron transfer mechanisms are not yet fully understood, recent research shows that the secretion of electron shuttles like flavins contribute significantly to the extracellular electron transfer (EET). Electron shuttle molecules like riboflavin (RB) or flavin mononucleotide (FMN) are secreted by MRB after the transition from planktonic to sessile mode and exist in the biofilm at low concentrations. Therefore, they are precise early phase indicators of bacterial settlement. This project aims at clarifying the electrochemical interaction mechanisms of MRB with stainless steel surfaces, with a special focus on the role of the extracellular redox molecules. The analysis of corrosion processes as a function of chloride and flavin concentration have been performed by means of electrochemical methods. Due to the differences in their chemical structure, FMN and RB have shown significant differences in terms of their adsorption behavior and the stability of the formed films, which directly influences the electron transfer processes. Therefore, Electrochemical Quartz Crystal Microbalance (eQCM) studies have been performed on sputtered FeCr electrodes to investigate the adsorption/desorption kinetics of flavins. The results of electrochemical studies are complemented by the analysis of the changes in the passive film chemistry and the chemical composition of the adsorbed films by means of Fourier Transform Infrared Reflection Absorption Spectroscopy (FT-IRRAS) and X-ray photoelectron spectroscopy (XPS). Changes in surface morphology have been investigated by means of Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM).The presentation will summarize our results on the degradation mechanisms of passive films on stainless steel surfaces in the presence of flavins and provide useful insights from a fundamental aspect for the understanding of the initial stages of microbiologically influenced corrosion. T2 - 17TH EUROPEAN CONFERENCE ON APPLICATIONS OF SURFACE AND INTERFACE ANALYSIS CY - Montpellier, France DA - 24.09.2017 KW - Flavins KW - Microbiologically influenced corrosion KW - Stainless steel KW - MIC PY - 2017 AN - OPUS4-43402 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Özcan Sandikcioglu, Özlem T1 - Nanotechnology at BAM N2 - The presentation gives a brief summary of the research activities of BAM in the field of nanotechnology. It was held at INERIS in the frame of a delegation meeting to identify topics for future collaborations. T2 - Kooperationstreffen mit INERIS CY - Verneuil-en-Halatte, France DA - 23.10.2017 KW - Nanotechnology KW - Nano Referenzmaterialien KW - Nanosafety PY - 2017 AN - OPUS4-43408 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Özcan Sandikcioglu, Özlem T1 - Spektroelektrochemische Analyse der Korrosionsprozesse von eisenreduzierenden Mikroorganismen N2 - Der Vortrag ist eine Zusammenfassung der Forschungsaktivitäten im FB 6.2 im Rahmen des Themenfeldprojekts MIC (TF-Material). T2 - DECHEMA/GfKORR-Fachgruppe "Mikrobielle Materialzerstörung und Materialschutz" CY - Berlin, Germany DA - 04.10.2017 KW - Korrosion KW - Mikrobiell induzierte Korrosion (MIC) KW - Lokale Elektrochemie KW - Spektroelektrochemie KW - Oberflächenverstärkte Raman Spektroskopie (SERS) KW - XANES PY - 2017 AN - OPUS4-43462 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -