Fe-Cr-Si-Alloys with Enhanced Resistance Against High Temperature Corrosion in the Presence of Molten Sulphate/Chloride Mixtures and HCl Containing Gases

摘要

Several Fe-Cr- and Fe-Cr-Si-alloys were exposed at 600 °C to N_2-5 vol. % O_2- 500 vppm HCl beneath deposits stemming from the superheater tubes of a waste incineration plant. The corrosion rates measured for the Fe-Cr-Si-alloys are about one order of magnitude lower than those observed for Alloy 625 and AC 66. The addition of 5 %Si prevents the chlorine catalysed active oxidation. Active oxidation seems to initiate the local metal consumption in the presence of molten sulfates. Fe-Cr-Si-alloys are promising coatings for the prevention of severe corrosion occuring on heat exchanger tubes in waste incineration plants.