TY - JOUR A1 - Chandra, Kamlesh A1 - Kranzmann, Axel A1 - Saliwan Neumann, Romeo A1 - Rizzo, F. T1 - Comparative study on high temperature oxidation of T92 steel in dry and wet oxyfuel environments N2 - Fireside oxidation of T92 steel was studied after exposure times up to 1000 h in the temperature range of 580–650 °C in simulated dry (CO2–27 % N2–2 % O2–1 % SO2) and wet (CO2–20 % H2O–7 % N2–2 % O2–1 % SO2) oxyfuel environments. Water vapour addition to the oxyfuel gas substantially increased the oxidation rate. The oxide scales developed under wet environment contained more defects, resulting in higher access of oxidants to the substrate material and enhanced oxidation. In addition, the oxide scales had lower chromium enrichment in the inner layer as compared to that in the dry condition. The oxide scales consisted of hematite and magnetite in the outer layer and a mixture of (Fe, Cr)-spinel, sulphides and wustite in the inner layer. The sulphur distribution differed between the oxide scales developed in dry and wet oxyfuel environments. Sulphur was mainly concentrated in the inner layer and at the oxide/alloy interface. In contrast to the wet oxyfuel gas, very high sulphur concentration was measured in the inner oxide scale formed in the dry oxyfuel gas. Additionally, Fe-sulphide was formed at the interface of inner and outer oxide layer in the wet condition. KW - Oxyfuel environment KW - Oxidation KW - High temperature corrosion KW - Water vapour KW - Sulphur PY - 2015 U6 - https://doi.org/10.1007/s11085-015-9565-0 SN - 0030-770X SN - 1573-4889 VL - 84 IS - 3-4 SP - 463 EP - 490 PB - Springer CY - New York, NY AN - OPUS4-34585 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chandra, Kamlesh A1 - Kranzmann, Axel A1 - Saliwan Neumann, Romeo A1 - Oder, Gabriele A1 - Rizzo, F. T1 - High temperature oxidation behavior of 9-12 % Cr ferritic/martensitic steels in a simulated dry oxyfuel environment N2 - The materials in oxyfuel power plant will be subjected to CO2– and SO2–rich gases on the fireside. The oxidation behaviour of two 9–12 % Cr steels T92 and VM12 was studied under dry oxyfuel environment in the temperature range of 580–650 °C for up to 1,000 h. The oxide structure and morphology were analyzed using various experimental techniques. A complex temperature dependence of oxidation rate is observed for both T92 and VM12 whereby the oxidation rate decreased with increasing temperature. This is attributed to increased Cr-enrichment in the inner scale with increasing temperature. T92 and VM12 alloys are also susceptible to carburization in an oxyfuel environment. KW - Oxyfuel environment KW - Ferritic/martensitic steel KW - Oxidation KW - High temperature corrosion KW - Carburization KW - Steel KW - EPMA KW - SEM PY - 2015 U6 - https://doi.org/10.1007/s11085-014-9521-4 SN - 0030-770X SN - 1573-4889 VL - 83 IS - 3-4 SP - 291 EP - 316 PB - Springer CY - New York, NY AN - OPUS4-32737 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Agudo Jácome, Leonardo A1 - Mosquera Feijoo, Maria A1 - Nolze, Gert A1 - Rizzo, F. ED - Militzer, M. ED - Botton, G. ED - Chen, L.-Q. ED - Howe, J. ED - Sinclair, C. ED - Zurob, H. T1 - Nano-sized precipitates in an Fe-13Cr alloy formed under oxidizing water vapor atmosphere N2 - Oxidation of a Fe –13Cr alloy under water vapor at 600°C produced a zone of nano-sized precipitation underneath the outside scale formed by iron oxides and Fe–Cr spinel. The majority of the spinel layer shows a fixed orientation relationship to the ferritic matrix: {1 0 0}α || {1 0 0}sp & <0 1 1>α || <0 0 1>sp . However, also the discovered precipitated particles are characterized by the same crystallographic orientation relationship to the respective ferritic parent grain. The habit of the precipitates is best described by a lath morphology with their main axis parallel to <1 0 0> of ferrite. Energy dispersive X-ray spectroscopy (EDX) and electron backscatter diffraction (EBSD) in scanning electron microscope (SEM) have been applied to characterize the oxide layer in micrometer scale. The clearly smaller precipitates were subsequently investigated by transmission electron microscopy (TEM). Specimens have been prepared by focused ion-beam (FIB) milling at an area previously characterized by EBSD. They cover the ferritic base material, but mainly the precipitation zone and the Fe–Cr spinel layer. Energy filtered selected area diffraction (SAD) in the conventional (C)TEM and high-angle annular dark field (HAADF) imaging in the scanning (S)TEM mode were employed in the characterization of the specimens. T2 - PTM 2015 - International conference on solid-solid phase transformations in inorganic materials CY - Whistler, BC, Canada DA - 28.06.2015 KW - Precipitation KW - Nano-crystals KW - Oxidation KW - Phase transformation KW - EBSD KW - TEM PY - 2015 SP - 379 EP - 386 AN - OPUS4-34444 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -