TY - JOUR A1 - Hünert, Daniela A1 - Schulz, Wencke A1 - Kranzmann, Axel T1 - Corrosion behavior of ferritic and martensitic power plant steels under conditions of dual atmospheres T2 - Corrosion N2 - The most efficient construction materials for boiler water walls and superheaters in steam power plants are ferritic and martensitic steels. In practical operation, tubes are exposed simultaneously to combustion gas and air/steam on their opposite surfaces. The corrosion behavior of ferritic-martensitic steels under such dual atmospheres is nondistinctive and has been investigated in a specially designed test equipment between 500°C and 620°C. The power plant conditions were simulated with a flowing and pressurized (80 bar) combustion gas on the inner side of the tube, which contains water (H2O) and carbon dioxide (CO2). On the outer side, tube material was exposed to air. Oxides that formed on the air side under dual atmosphere conditions were significantly different from the oxide scales formed when the alloy was exposed to air only. It is assumed that the anomalous corrosion behavior during the dual atmosphere exposure is due to hydrogen and carbon diffusion through the bulk alloy from the combustion gas side to the air side. Both species are produced when the material reacts with the gas phase. Because of its high diffusivity, hydrogen is thought to affect the corrosion process on the air side from the beginning of the corrosion exposure, whereas carbon reaches the opposite side after a considerably longer time period. PB - National Association of Corrosion Engineers CY - Houston, Tex. KW - Chromium steels KW - Corrosive gases KW - Dual atmosphere KW - High-temperature corrosion KW - Hydrogen transport KW - Mild steel PY - 2010 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/23217 AN - OPUS4-23217 SN - 0010-9312 SN - 1938-159X VL - 66 IS - 12 SP - 126001-1 - 126001-7 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany