Carbon induced metal dusting of iron-nickel-chromium alloy surfaces: a scanning auger microscopy study

In this work, we present an investigation on metal dusting of iron-nickel-chromium (Fe-Ni-Cr) alloy surfaces using scanning auger microscopy. It is shown that the formation of surface Cr-oxide and the surface finish condition can strongly influence and interrupt this catastrophic phenomenon. The accumulation of C within the metal matrix was not always prevented by the Cr-oxide layer. The formation of Cr-oxide was accompanied by a depleted Cr layer (next to the oxide layer) with a depth of several hundreds of nanometers. The depleted Cr layer was significantly broader if the C diffusion within the metal matrix was prevented, while no preferential enrichment of Ni or Fe close to the alloy surface was observed.