High Temperature Corrosion of Stainless Steel, Inconel and Incoloy Alloys in Bromine-containing Atmosphere

Practical heat-resisting alloys such as stainless steel 304, Inconel 625 and Incoloy 825 showed a significant mass loss (active corrosion) and a mass gain (passive corrosion), respectively, at a low and a high oxygen partial pressure in a bromine-containing atmosphere around 1000 K. The transition oxygen partial pressures from the active to passive corrosion for these alloys were about 0.05 to 0.2 kPa at 1073 K. This result was almost in agreement with the thermodynamic calculations by an optimization method. The addition of water vapor (PH2O=1.17 kPa) at 1073 K and PO2=0.063 kPa caused the change from the active to passive corrosion for stainless steel 304 but not for Inconel 625. This behavior was also explained with the thermodynamic calculations.