Hardness, magnetism and passivation of Fe-Si-B-Nb glasses

Abstract Nb is a noble and important element for the Fe based glass manufacture. The mechanical properties, magnetic properties and corrosion behavior of (Fe78Si9B13)100-xNbx (x = 0, 7 and 10) glassy ribbons have been studied by various experimental methods. With the addition of Nb element, the hardness of the Fe-based glasses increases and their coercivity decreases, which is attributed to the ordering tendency of atomic structure by adding Nb atoms. In the potentiodynamic polarization and Mott-Schottky plots, Fe-based glassy ribbons with x = 7 and 10 have a wide passivation platform and an n-type semiconductive surface, while the ribbon with x = 0 does not. By XPS analysis, Nb and B tend to segregate beneath the ribbon surface and form the stable passive film. The Nb addition can improve the hardness, soft magnetism and corrosion resistance of Fe based glasses and will help us to seek for the new type Fe based glasses.