Effect of structural evolution and surface morphological changes on the electrochemical response of an FeNbAlMnCuSiB alloy

The electrochemical response of a soft magnetic FeNbAlMnCuSiB alloy was studied through different stages of devitrification. The structural evolution including appearance of a nanocrystalline phase and intermetallics, and accompanying surface topographical changes were studied and correlated to the electrochemical behavior of this alloy. The electrochemical behavior was not directly related to changes in surface roughness but it was very responsive to the structural changes, particularly to the formation of the nanocrystalline phase and to the precipitation of Fe7Nb6 phase. There was a progressive passivation breakdown with the appearance of crystalline phases on annealing.