## 3 Results and Discussion
The oxygen equilibrium line potential is calculated according to Nernst equation at RT (see Equation (1)):  
\[E_{\rm O_{2}/OH^{-}}=E_{\rm O_{2}/OH^{-}}-0.059\log\frac{\left[\rm OH^{-} \right]}{p_{O_{2}}^{1/4}} \tag{1}\]  
where \(E_{\rm O_{2}/OH^{-}}\) is the reversible potential of the oxygen, \(E_{\rm O_{2}/OH^{-}}\) is the standard reduction potential, 0.401 V\({}_{\rm SHE}\) for alkaline media, \(\log\left[\rm OH^{-}\right]\) is a function of the pH, and \(p_{O_{2}}\) is the partial pressure of O\({}_{2}\) and equals 1 atm. For the synthetic FA pore solution, the oxygen equilibrium line is at 0.160 V\({}_{\rm SCE}\). It can be seen from Table 2 how the as-received and normalized samples have the largest ORR kinetics. In addition to the \(i_{\rm 0,ORR}\), the anodic and cathodic charge transfer coefficients can be obtained and discussed using Equations (2) and (3), respectively [49]:  
\[\alpha_{\rm a}=\frac{RT}{nF}\frac{1}{\beta_{\rm a}} \tag{2}\]  
\[\alpha_{\rm c}=\frac{RT}{nF}\frac{1}{\beta_{\rm c}} \tag{3}\]  
where \(\alpha_{\rm a}\) and \(\alpha_{\rm c}\) are the anodic and cathodic charge transfer coefficients, respectively, \(R\) is the ideal gas constant (8.314 J mol\({}^{-1}\) K\({}^{-1}\)), \(T\) is temperature in K, \(n\) is the number of electrons, \(F\) is the Faraday constant (96,485 C mol\({}^{-1}\)), and \(\beta_{\rm a}\) and \(\beta_{\rm c}\) are the anodic and cathodic Tafel slopes in V/dec. The \(\alpha_{\rm a}\) varies among the different thermomechanical treatments, indicating an anodically controlled electrochemical corrosion process, thus showing the influence of the phases present in the microstructure on the dissolution kinetics. However, the \(\alpha_{\rm c}\) does not vary with the applied thermomechanical treatment as all the values fall in the range of 0.100 \(\pm\) 0.04, indicating that the process is not controlled by the ORR. Before performing the EIS analysis, Kramers-Kronig (KK) transforms were produced to determine robustness of the data. The analysis consists of calculating the real impedance values using the imaginary experimental data and vice versa. In order to determine the robustness of the experimental data, both results, experimental and calculated data, must have a good correlation [50,51]. This can be seen in Figure 6, where the empty symbols \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Specimen** & \(i_{\rm corr}\) & \(E_{\rm corr}\) & \(\beta_{\rm a}\) & \(\beta_{\rm c}\) & \(B\) & \multirow{2}{*}{\(\alpha_{\rm a}\)} & \multirow{2}{*}{\(\alpha_{\rm c}\)} & \(i_{\rm 0,ORR}\) \\  & **(A/cm\({}^{2}\))** & **(V\({}_{\rm SCE}\))** & **(V/dec)** & **(V/dec)** & **(mV)** & & & **(A/cm\({}^{2}\))** \\ \hline As-received & 2.13 \(\times\) 10\({}^{-6}\) & \(-\)0.500 & 0.091 & 0.181 & 26.33 & 0.282 & 0.142 & 5.91 \(\times\) 10\({}^{-8}\) \\ Normalized & 1.84 \(\times\) 10\({}^{-6}\) & \(-\)0.423 & 0.265 & 0.208 & 50.67 & 0.097 & 0.124 & 1.77 \(\times\) 10\({}^{-8}\) \\ Annealed & 2.09 \(\times\) 10\({}^{-5}\) & \(-\)0.561 & 0.252 & 0.269 & 56.57 & 0.102 & 0.096 & 1.18 \(\times\) 10\({}^{-9}\) \\ Water quenched & 3.18 \(\times\) 10\({}^{-5}\) & \(-\)0.496 & 0.292 & 0.295 & 63.80 & 0.088 & 0.087 & 4.86 \(\times\) 10\({}^{-9}\) \\ Oil quenched & 2.20 \(\times\) 10\({}^{-5}\) & \(-\)0.504 & 0.284 & 0.271 & 60.29 & 0.091 & 0.095 & 4.12 \(\times\) 10\({}^{-9}\) \\ WQ + Sub. Annealing & 2.18 \(\times\) 10\({}^{-6}\) & \(-\)0.592 & 0.182 & 0.231 & 44.26 & 0.141 & 0.111 & 3.48 \(\times\) 10\({}^{-9}\) \\ OQ + Sub. Annealing & 2.77 \(\times\) 10\({}^{-6}\) & \(-\)0.615 & 0.232 & 0.245 & 51.81 & 0.111 & 0.105 & 1.79 \(\times\) 10\({}^{-9}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: \(E_{\rm corr}\) and \(i_{\rm corr}\) parameters obtained via CPP of CS samples in FA pore solution (pH 13.6). represent the experimental values and the crosses represent the calculated values, the overlapping indicates a good fit, thus showing the robustness of the data obtained.