Oxidation behavior of NiCrAlYSi coatings with Re-based diffusion barriers on two superalloys

The NiCrAlYSi coatings with or without Re-based diffusion barriers (DB) were prepared on K438 and K465 superalloys by electroplating Re-Ni layer, arc ion plating (AIP) NiCrAlYSi coating and following vacuum annealing. Isothermal oxidation behaviors of all coatings were investigated at 1100 ℃ in static air. The results showed that better oxidation resistance was achieved for NiCrAlYSi coatings with Re-based DB and for NiCrAlYSi coatings on K438 than that on K465. Re diffused into NiCrAlYSi coatings during isothermal oxidation and increased spallation resistance of oxide scale. The role of Re-based DB and the effects of substrate compositions were discussed.