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 - SiO 2 KW - Polyaniline KW - Corrosion PY - 2018 SP - 10708, 1 EP - 14 PB - Omnipress CY - Houston AN - OPUS4-44916 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Aristia, G. A1 - Le, Quynh Hoa A1 - Bäßler, Ralph A1 - Roth, C. T1 - The Effect of Different Polyaniline Types in Silicon Dioxide Containing Coatings for Carbon Steel Protection in Artificial Geothermal Brines N2 - According to the results of the experiments carried out, the following points can be concluded: 1. Exposure tests showed that specimens with the addition of SiO2 particles and polyaniline particles exhibit better corrosion resistance than specimens with the addition of only polyaniline particles or binder only. 2. Open circuit potential measurements showed that in the beginning of the experiments, both coatings had an open circuit potential 100 mV higher than carbon steel. Within one day of immersion, the potential of carbon steel increased significantly, indicating the formation of oxide layer. After extended exposure the carbon steel potential sat between PS1 (which had higher potential) and PS2 (which had a lower potential) and all three were in the range –600 mV to –500 mV vs Ag/AgCl. 3. Both coatings PS-1 and PS-2 were degraded with increasing exposure time, shown by the decrease of absolute impedance value at low frequency range after 2, 4, and 6 days exposure. 4. Potentiodynamic test was performed after 3 hours and 6 days exposure, and it was shown that the coating in the initial stage exhibited more passive behavior than the specimens exposed for 6 days. T2 - NACE International Corrosion Conference 2019 CY - Nashville, TN, USA DA - 24.03.2019 KW - Geothermal KW - Coating KW - Polyaniline KW - Corrosion PY - 2019 SP - 13121-1 EP - 13121-14 PB - NACE International CY - Houston AN - OPUS4-47913 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Roth, C. A1 - Schalley, C. A. A1 - Unger, Wolfgang T1 - Incorporating mechanically interlocked molecules into crystalline coordination networks on surfaces: Electro-active SURMOFs to translate molecular switching into macroscopic function and devices N2 - We aim at preparing, characterising, and applying SURMOFs incorporating electro-active and -switchable mechanically interlocked molecules such as rotaxanes as the basis of functional devices. Preparation and Positioning Synthesis, purification and analytical characterization of electro-switchable rotaxanes suitable for SURMOF-formation as well as Layer-by-Layer assembly on surfaces. Controlled deposition of electro-active SURMOFs and Layer-by-Layer self-assembled multilayers based on these switchable rotaxanes. Construction of SURMOFs on micro-patterned surfaces. Structural Characterisation and Physico-Chemical Properties Electrochemical characterization of these rotaxanes in solution with cyclic voltammetry, chronoamperometry and impedance spectroscopy. Surface characterization of SURMOFs and multilayers with XPS, NEXAFS, AFM, contact-angle measurements, transmission UV/Vis, ToF-SIMS and – in cooperation with partners from SPP – XRD. Development of ToF-SIMS (also assisted by Principle Component Analysis of the fragment-ion data) as a method for imaging and depth-profiling. Development of an appropriate electrochemical cell to perform cyclic voltammetry, chronoamperometry and impedance spectroscopy with SURMOFS and multilayers as working electrodes in a three-electrode cell. Comparison of the structural and electrochemical properties of the redox-active unit in solution, multilayers and SURMOF focusing on the advantages of SURMOFs. System Integration and Function Demonstration Examination of the usability of the electroactive SURMOFS as optoelectronic switch or data storage device with a focus on the robustness of the system. Usage of the SURMOFs as functional electrodes for electrochemical application. Selective switching of ordered nanostructures to translate molecular motion to macroscopic property changes. T2 - Colloquium of the Priority Programme "Coordination Networks: Building Blocks for Functional Systems” SPP 1928 CY - Garching, Germany DA - 30.3.16 KW - SURMOF KW - XPS KW - NEXAFS KW - Characterization PY - 2016 AN - OPUS4-35868 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -