Low inter-diffusivity γ'-base bondcoats for single crystal superalloy Rene N5.II: Cyclic oxidation behavior at 1100 ℃

摘要

Three gamma'-base coatings of Hf-doped and Re-modified NiCoCrAlTaY system were deposited on Rene N5 superalloy by magnetron sputtering. The cyclic oxidation behavior of these coatings was investigated at 1100 degrees C for 500 h. The gamma'-base coatings exhibited excellent resistance against coating/substrate interdiffusion and coating rumpling. The TGO was mainly alumina. Minor TGO spallation occurred on coatings with (similar to)19 at.% and 20 at.% Al, which may be correlated with the formation of Ta-rich oxide particles within TGO scales, while severe TGO spallation occurred on coating with (similar to)25 at.% Al, which may be correlated with the formation of voids at TGO/coating interface.