CYCLIC OXIDATION BEHAVIOR OF MULTILAYER NiCrAlYSi/Ru-Al COATINGS ON THE DZ125 SUPERALLOY

The fabrication of the Ru-Al modified multilayer NiCrAlYSi coatings was developed via arc ion plating technique (AIP), including the Ru-Al layer deposited by detonation spraying technology. The cyclic oxidation behavior of NiCrAlYSi coatings containing the Ru-Al composite layer at various locations was investigated. The evolution of the microstructure at various stages of cyclic oxidation and the relevant interdiffusion between the NiCrAlYSi and Ru-Al layer were studied. The results indicated that the Ru-Al modified NiCrAlYSi coating with the Ru-Al layer on the top of NiCrAlYSi layer exhibited better oxidation resistance and performance than the conventional NiCrAlYSi coating. The ruthenium contained in the Ru-Al layer diffused toward the NiCrAlYSi layer more easily and quickly than toward the substrate during cyclic oxidation at 1100 degrees C. The addition of the Ru-Al layer promoted the formation of alumina scale in the early stage of oxidation, which protected the coating system from further oxidation effectively. The NiCrAlYSi coatings modified by the Ru-Al layer were developed by the combination of arc ion-plating and detonation spraying technology, which is an economic and effective method for Ru deposition.