Abstract:Ni₃Al coatings with and without Y₂O₃ particles were developed by annealing the electrodeposited Ni-Al composite coatings with and without Y₂O₃ particles at 800 °C for 3 h. The microstructures and cyclic oxidation performances of the produced Ni₃Al coatings were comparatively investigated, with the emphasis on the effect of Y₂O₃. SEM/EDAX and TEM characterizations showed that the dispersion of Y₂O₃ refines the grains. Oxidation at 900 °C for 100 h showed that the addition of Y₂O₃ significantly improved the cyclic oxidation resistance of Ni₃Al coating. The effect of Y₂O₃ on the microstructure and the oxidation of the Ni₃Al coating were discussed in detail.

Key words: electrodeposition; Ni₃Al; cyclic oxidation; reactive element effect