Influence of Al addition on the corrosion resistance and magnetic properties of FeZrNbBCu alloy

In this paper, the influence of Al addition on the magnetic properties and corrosion resistance of amorphous and nanocrystalline FeZrNbBCu alloy were investigated. Small additions of Al affect not only the magnetic properties but also the increment of corrosion resistance. The corrosion resistance of nanocrystalline alloy was obviously lower than that of the amorphous alloy. The reason can be explained by the fact that the uniformity of the passive film was affected and decreased the corrosion resistance for the formation of nanocrystalline embedded in the amorphous alloy. The Al addition is effective in improving the corrosion resistance and will lead to the increase of the relaxation frequency when the Al content is over 2 at%. A layer of protective oxides was formed in the surface of the ribbons after corrosion. The two magnetization processes in the corroded samples were attributed to the coexistence of the surface oxide layer and the inner un-corroded layer of the ribbons.