Iron-aluminide filters for hot-gas cleanup

Iron aluminides have shown good to excellent high-temperature corrosion resistance in sulfur-bearing environments and thus have potential for use as the material of construction for metallic filters used to clean fossil-fuel-derived gases prior to their introduction into gas turbine systems. Consequently. a background for consideration of such alloys for filter applications is given in terms of a brief summary of the physical metallurgy and relevant high-temperature corrosion behavior of iron aluminides. In addition, preliminary characterization results on ironaluminide filter elements exposed in test beds that simulate environments associated with advanced coal-fired energy production are presented. Although good corrosion resistance was found, there were minor to moderate strength reductions that did not necessarily scale with time. Little degradation in ductility was observed.