Effect of annealing treatment on cyclic-oxidation of electrodeposited Ni-Al nanocomposite

An electrodeposited Ni-Al nanocomposite having a nanocrystalline Ni matrix dispersing Al nanoparticles was annealed in vacuum at 500 °C for different time (3, 5 and 8 h, respectively). The results show that the annealing treatment leads to the reaction of Ni and Al to form intermetallics and the coarsened Ni grains that are doped with a certain amount of Al atoms diffused from the nanoparticles. Cyclic oxidation in air at 1 000 °C indicates that the scale spallation resistance of the annealed Ni-Al nanocomposite increases with the increase of annealing time, due to prevention of the composite intergranular cracking during the cycling, reduction of numerous surface NiO nodules formed on the scale spalled area and prevention of internal oxidation.