The electrochemical corrosion behavior of Pb-0.23 wt.% Ca-0.93 wt.% Sn and Pb-0.23 wt.% Ca-0.92 wt.% Sn-0.18 wt.% Sm alloys in 4.8 M H2SO4 at 25
C was studied using open circuit potential (OCP), cyclic polarization, electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV) and Mott eSchottky plot. The findings of this study show that the samarium added to PbeCaeSn alloy increases the general corrosion resistance of this alloy and inhibits the growth of the anodic corrosion layer, it can promote the pitting corrosion tendency of PbeCaeSn alloy. MotteSchottky plot also reveals that the anodic films on PbeCaeSn and PbeCaeSneSm alloys at þ1.5 V vs. SCE exhibit an n-type semi-conductive character. Sm increases the slope of MotteSchottky plot, implying the reduction of the defect density within the anodic film, which is beneficial to increase the resistance of anodic film.

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