CORROSION BEHAVIOUR OF P9 AND P91 ALLOYS IN SUPERCRITICAL FOSSIL FUEL BASED POWER PLANT

摘要

Oxidation behaviour of steels containing 9-12 percent Cr (alloys P9 and P91), has been investigated. Preliminary tests have been carried out in air at temperatures ranging from 600 to 800 deg C. The oxidation kinetics of P91 alloys shows parabolic behaviour at temperatures 600 and 700 deg C. However, at 800 deg C the oxidation kinetics shows breakaway oxidation after a short duration of exposure. In short-term oxidation process, the alloy P9 shows higher oxidation rate compared to P91 alloy at 600 deg C. The alloy P9 shows parabolic behaviour during long-term oxidation process at 600 deg C, whereas alloy P91 shows breakaway oxidation after 600 hours. The oxide scales are characterized using SEM and XRD.