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 corrosi on resistance is a desirable property in such alloys, no study concerning t his aspect has been reported. The effect of metalloid content and partial c rystallization on corrosion resistance of Fe-M-B (M=Zr, Nb) amorphous alloy s, Fe84Nb7B9, Fe84Zr7B9 and Fe83Zr3.5B9Cu1, was investigated. Corrosion res istance measurements were carried out by mass loss, potentiodynamic polariz ation. and thermogravimetric mass gain measurements. The partial crystalliz ation of the amorphous alloy results in a decrease of the corrosion resista nce for all the compositions analyzed. We also observed a greater corrosion resistance when Nb was present in comparison to the case when Zr was prese nt. These results are an effect of the superficial passive film protector f ormed. (C) 2000 Published by Elsevier Science B.V. All rights reserved.