Effect of Cyclic Reaction on Corrosion Behavior of Chromium-Containing Alloys in CO2 Gas at 650 °C

Corrosion Behavior of Cr-Containing Alloys under Cyclic Reaction in Wet CO2 Gas at 650°C

“…Alloys (602CA, 310SS, 253MA, 800H) after annealing in Ar-5H 2 gas for 150 h at 650°C generated carbide precipitants at all grain boundaries in the whole cross-section. Therefore, additional carbide formation, if any, due to the gas reaction cannot be clearly identified for these alloys [4]. However, after annealing in Ar-5H 2 at 650°C, alloys F321, F316L and 304SS also showed carbide formation, but with much less density.…”

“…The electropolishing method was applied to remove the surface deformation zone created during sample preparation. Details about sample preparation are described elsewhere [4].…”

“…3. In dry gas, a thin and uniform chromia scale formed for both alloys [4]. However, in wet gas they experienced certain extents of attack during 310 h reaction.…”

“…Figure 1 compares the weight changes of alloys after 310 h exposure to Ar-20CO 2 and Ar-20CO 2 -20H 2 O. All the 3 more protective alloys (602CA, 310SS, 253MA) identified in dry gas [4] showed obvious weight increases when water vapor was added to the gas mixture (Fig. 1a).…”

“…Austenitic alloys might be more susceptible to thermal-cyclic reaction, owing to their significantly higher thermal expansion coefficients than those of ferritic/martensitic steels [3]. A preliminary study found that the cyclic reaction accelerated the formation of iron-rich nodules for high-chromiumcontaining austenitic alloys in dry CO 2 [4]. As the atmosphere related to oxyfuel combustion always contains H 2 O, it is necessary to determine the role of water vapor on the corrosion behaviors of austenitic alloys in CO 2 under cyclic reaction conditions.…”