Corrosion resistance of amorphous and nanocrystalline Fe–M–B (MZr, Nb) alloys

Amorphous Fe–M–B (MZr, Nb) based alloys with nanometer-sized crystallites have attracted attention due to their magnetic properties. Although corrosion resistance is a desirable property in such alloys, no study concerning this aspect has been reported. The effect of metalloid content and partial crystallization on corrosion resistance of Fe–M–B (MZr, Nb) amorphous alloys, Fe84Nb7B9, Fe84Zr7B9 and Fe83Zr3.5Nb3.5B9Cu1, was investigated. Corrosion resistance measurements were carried out by mass loss, potentiodynamic polarization, and thermogravimetric mass gain measurements. The partial crystallization of the amorphous alloy results in a decrease of the corrosion resistance for all the compositions analyzed. We also observed a greater corrosion resistance when Nb was present in comparison to the case when Zr was present. These results are an effect of the superficial passive film protector formed.