Corrosion comparison of free and roller surfaces of Fe70Si8B12Nb10 amorphous ribbon.

The corrosion resistance of the free surface (FS) and roller surface (RS) of Fe70Si8B12Nb10 amorphous ribbon was systematically compared in simulated seawater (0.6 M NaCl). The electrochemical method and scanning electron microscopy showed that the FS corrosion resistance was higher than that of the RS. XPS etching and Mott-Schottky tests indicated that the passivation films on the FS and RS were divided into outer and inner layers. In the spinning process, the elements with a higher atomic mass tend to segregate toward the FS, while the elements with a lower atomic mass segregate toward the RS. These results provide data that can be used to improve the quality of melt spinning ribbons and to optimize the manufacturing of involved electric devices. This journal is © The Royal Society of Chemistry.