The electrochemical corrosion properties and effect of microstructures on them of a coarse grained and two nanocrystalline Fe-50Cu bulk alloys prepared by powders metallurgy (PM) as well as the liquid phase reduction (LPR) and mechanical alloying (MA) methods with hot pressing, respectively, were investigated in H2SO4 solutions by means of electrochemical methods through measuring open circuit potentials, potentiodynamic polarization, electrochemical impedance spectroscopies, and so on. The results show that the corrosion current densities of three Fe-50Cu alloys prepared by the different methods increase with the increment of H2SO4 solution concentrations. Their electrochemical impedance spectroscopies are composed of a single capacitive arc, indicating the corrosion processes are controlled by the electrochemical reactions. The changed trend of charge transfer resistances of three Fe-50Cu alloys is adverse to that of corrosion current densities. In the same H2SO4 solution concentrations, the corrosion current densities increase and therefore corrosion properties decrease when the grain sizes are decreased. The corrosion current densities of LPR Fe-50Cu alloy are larger, the activation energies and charge trnasfer resistances are lower and therefore its corrosion rates are faster than those of nanocrystalline MA Fe-50Cu alloy. © 2020, Materials Review Magazine. All right reserved.
