An Electrochemical Impedance Study of AISI 321 Stainless Steel in 0.5 M H₂SO₄

Figure 1

Interfacial defect generation-annihilation reactions that are postulated to occur in the growth of anodic barrier oxide films according to the PDM. 𝑚 = metal atom, V^𝜒−_M = cation vacancy on the metal sublattice of the barrier layer, M^𝜒+_i = interstitial cation, M_M = metal cation on the metal sublattice of the barrier layer, V^⋅⋅_O = oxygen vacancy on the oxygen sublattice of the barrier layer, O_O = oxygen anion on the oxygen sublattice of the barrier layer, M^Γ+ = metal cation in solution [10–13].