Anodic reactions of amorphous and devitrified Fe–B–Si–Nb–Cu alloys in buffered chloride and fluoride

The anodic response of two Fe–Si–B–Cu–Nb alloys was investigated in buffered chloride and fluoride media through polarisation studies and corrosion product analysis. It was found that the anodic reactions and dissolution of the alloys were dependent on the alloy compositions as well as the state (amorphous or crystalline) of the alloy substrate. It was observed that crystallisation resulting in the formation of the ordered Fe80Si20 phase only, was beneficial to corrosion resistance in chloride media, however the presence of secondary intermetallic phases was detrimental. The anodic responses in the fluoride media were dominated by the formation of fluorosilicate.