Development of a metal dusting resistant functional coating by Sn and Al pack cementation

•New coating against metal dusting as well as oxidation at high temperatures is presented.•The coating concept combines oxide barrier formation and catalytic inhibition approach.•Oxide scale formation during exposure in carbon containing, reducing as well as oxidizing atmosphere at 620 °C.

A new coating against metal dusting is developed by the combination of a catalytic inhibition approach with a classical oxide barrier. Coatings were manufactured by co-deposition of tin and aluminum on nickel plated alloy 800H via powder pack cementation with different dwell times. The resulting coatings consist of two phases, a nickel-aluminide phase as oxide forming reservoir and an underlying nickel-tin phase which catalytically inhibits carbon deposition. Coated samples were exposed to H2-22%CO-10%H2O as a laboratory metal dusting environment as well as air at 620 °C. Cross sectional analysis revealed no sign for metal dusting and the formation of a thin alumina layer at the surface.