| Abstract: | High temperature corrosion of 2.25Cr-1Mo in simulated waste incineration environments The corrosion of the 2.25Cr-1Mo steel was investigated by thermogravimetry in He? O2? HCl? SO2 at 500°C with and without deposits, taken from a waste incinerator. Additions of 500 vppm HCl to He-O2 without deposits lead to accelerated corrosion due to the formation of FeCl2 at the metal/oxide interface, its evaporation and oxidation lead to Fe2O3 at the outer surface (“active oxidation”). SO2 causes FeS2 formation on the FeCl2 which retards the corrosion process. Under deposits, accelerated corrosion was observed in He-O2 due to the reaction of alkalichlorides of the deposits with the oxide scale to ferrate and chlorine, which causes active oxidation. In He? O2? HCl occurs strongly accelerated corrosion, due to transformation of the sulfates in the deposits by reaction with HCl to alkalichlorides. Addition of SO2 shifts this equilibrium to enhanced stability of the sulfates, thus the corrosion in He? O2? HCl? SO2 is reduced. |
