Effect of CeO2 on the microstructure and isothermal oxidation of Ni-Al alloy coatings transformed from electrodeposited Ni-Al films at 800 °C

The electrodeposited two-phase γ-Ni + γ′-Ni3Al and single-phase γ′-Ni3Al coatings with and without CeO2 particles were developed by the conversion of electrodeposited Ni-Al or Ni-Al-CeO2 films with dispersed Al microparticles in Ni matrix into γ′-Ni3Al by vacuum annealing at 800 °C for 3 h. SEM/EDAX and TEM characterizations showed that the CeO2-dispersed γ-Ni + γ′-Ni3Al or γ′-Ni3Al coatings exhibited finer grains compared to the CeO2-free Ni-Al alloy coatings. The oxidation at 1000 °C for 20 h showed that for a given Al content the addition of CeO2 significantly improved the oxidation resistance of the electrodeposited Ni-Al alloy coatings. The effect of CeO2 particles on the microstructure and oxidation behavior of the electrodeposited Ni-Al alloy coating is discussed in detail.