Electrochemical investigations on Fe-Si alloys with different Si content (1.9 ai percent to 50.0 at percent) were carried out in nitrogen-purged acidic (pH =5.0) and weakly alkaline (pH =8.4) solutions. The passivation behavior of these alloys is dependent on the Si content, which leads to three different phases of the bulk metal consisting of #alpha#-Fe (1.9 at percent to 7.6 at percent Si), Fe_3Si (21.3 at percent to 25.1 at percent Si), and FeSi-phase (50 at percent Si). The phase composition influences the formation mechanisms, growth kinetics, thickness, and composition of passive layers. Results showed the positive influence of Si on the stability and electrochemical properties of passive layers on Fe-Si alloys.
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