Air-oxidation behavior of a [(Fe50Co50)(75)B20Si5](96)Nb-4 bulk metallic glass at 500-650 degrees C

Abstract

The oxidation behavior of a [(Fe50Co50)75B20Si5]96Nb4 bulk metallic glass was studied over the temperature range of 500–650 °C in dry air. The oxidation kinetics generally followed the parabolic-rate law, and the parabolic-rate constants (kp values) of the glassy alloy increased with increasing temperature. The kp values of the glassy alloy were lower than those of the binary FeCo alloy. The scales formed on the FeCo alloy consisted of Fe3O4 and minor Fe2O3, while B2O3 was also observed on the amorphous substrate, whose formation may be responsible for the slower oxidation rates of the glassy alloy.