Cyclic oxidation behavior of Hf/Zr co-doped EB-PVD β-NiAl coatings at 1200 °C

The reactive element of Hf or Zr doped and Hf/Zr co-doped beta-NiAl coatings was prepared by electron beam physical vapor deposition (EB-PVD). Cyclic oxidation behavior of the coatings at 1200 degrees C was compared. The Hf/Zr co-doped NiAl coating revealed finer grain size than the Hf or Zr single-doped coatings. Hf/Zr co-doping led to lower oxide scale growth rate than Hf or Zr single-doping. No oxide scale spallation was observed on the surfaces of the NiAlHf and NiAlHfZr coatings after 100 h cyclic oxidation, indicating improved high-temperature cyclic oxidation resistance, as compared to the NiAlZr coating. Related mechanisms were preliminarily discussed. (C) 2015 Elsevier B.V. All rights reserved.