Preparation and cyclic oxidation resistance of Hf-doped NiAl coating

NiAl coating, 5Hf-NiAl coating and 15Hf-NiAl coating were prepared on Ni-based superalloy by electroplating, arc ion plating (AIP) and subsequent vacuum annealing. Cyclic oxidation behavior of the three coatings was investigated at 1100 ℃. 5Hf-NiAl coating and 15f-NiAl coating exhibited excellent adhesion between thermally growth oxide (TGO) and coating. The uniformly dispersed Hf-rich precipitates contributed to the cyclic oxidation resistance. The oxidation mechanism and effect of Hf on the morphologies, rumpling and adhesion of TGO were discussed as well.