| Abstract: | Phenomena of metal dusting on iron and nickel (and their alloys) were studied by characterizing both microstructure and nanochemistry of the reaction zones using TEM and AEM techniques. While in case of iron a metastable carbide (cementite) is formed nickel directly disintegrates. In the chromium-rich steel HK40 and the chromium-rich Ni-base alloy Inconel 600 some microstructural chromium dependent features were observed with protective effects against metal dusting. Independent of these differences, in all groups of materials a fundamental common starting mechanism on the atomic scale could be deduced, which first of all comprises the arrangement of basal graphite lattice planes perpendicularly oriented to the carbide (or metal) surface acting as active sites in the disintegration process. |
