Preparation and oxidation of an Al2O3-modified aluminide coating

Abstract: An Al2O3-modified aluminide coating was produced by aluminizing an as-electrodeposited Ni–Al2O3 nanocomposite film using pack cementation method at 1100  C for 4 h. For comparison, aluminizing was also performed in the same condition on an as-deposited Ni film without Al2O3 nanoparticles. SEM/EDAX and TEM results indicated that the co-deposited Al2O3 nanoparticles were homogeneously dispersed in the finer-grain nanocrystalline Ni grains. The isothermal and cyclic oxidation in air at 900 °C indicated that the Al2O3-modified aluminide coatings were profoundly oxidation resistant as compared to the Al2O3-free aluminide coatings due to the faster formation of a continuous adherent α-Al2O3 scale. The effect of Al2O3 on the microstructure and the oxidation of the aluminide coating are discussed in the detail. [Copyright &y& Elsevier]