## 1 Introduction
The corrosion rates of the materials proposed in the abovementioned publication can be seen in Table 1.  
The use of different electrochemical tests is a powerful monitoring technique that is widely used in many diverse fields, including energy. The data obtained can be used to find certain physical properties, such as diffusion coefficients, chemical reaction rates and microstructural characteristics of the electrochemical system under study. Linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS) tests provide information on the corrosion rate, as well as information on the kinetics of the corrosion process that helps to identify the different anodic and cathodic \begin{table}
\begin{tabular}{c c c} \hline
**Composition of Steel** & **Generic Name of Steel** & **Descaled Weight Loss (mg/cm\({}^{2}\))** \\ \hline
0.2\% Cr & SB450 & 13.75 \\
2.25 Cr-1 Mo & T22 & 12.44 \\
5 Cr-0.5 Mo & T5 & 9.89 \\
9 Cr-1 Mo & T9 & 1.19 \\
12 Cr-1 Mo & X20 & 0.50 \\ \hline \end{tabular}
\end{table} 
Table 1: Corrosion from descaled weight losses of steel specimens following exposure to molten salt at 550 \({}^{\circ}\)C for 1000 h. (Adapted from [10]). reactions [12; 13; 14]. They also help to identify the different materials that are susceptible to corrosion under specific conditions. The electrochemical technique linear polarization resistance (LPR) is a method in which the electrochemical response of a corroding metal is investigated near its open circuit or corrosive potential. Typically, this involves polarization of the material of interest below the corrosion potential and a slow increase (or scan) of the potential to the comparable potential above the corrosion potential. Within this potential region, it is assumed that the relationship between potential and log current is linear, thereby allowing the calculation of the corrosion rate [15]. Electrochemical impedance spectroscopy (EIS) is a method that uses a small voltage signal between different amplitudes over an equilibrium or other known potential, which causes the induced current to be measured while the voltage is modulated in different frequency ranges. In contrast, the electrochemical impedance spectroscopy (EIS) test is represented by the Nyquist and Bode graphs, where the former represents the system impedance in real and imaginary coordinates and the latter describes the modulus and phase angle of the impedance. The spectrum analysis in the Nyquist graph requires fitting using equivalent electrical circuit models where this model shows different aspects of the corrosion process [16; 17; 18]. The corrosion of molten salts can take different forms, such as, for example, uniform corrosion, localized corrosion, and internal corrosion. Considering the chemical stability of different metals in molten salts, the metals can be divided into two groups, active metals and non-active metals. The active metals can undergo corrosion by the molten salts, forming a layer that can be porous or protective [19; 20; 21; 22]. Based on the considerations above, the following models can be used to describe the general situation of metals in molten salt systems, which are shown in Figure 1.  
Figure 1: Nyquist plots and the equivalent circuits representing the corrosion of metals in molten salts. (**a**) Representation of a non-active metal; (**b**) active metals forming a porous scale; (**c**) active metals forming a protective scale; (**d**) active metals suffering from localized corrosion. (Adapted from [21]). To complement the corrosion mechanisms through electrochemical testing, it is necessary to understand the fundamental chemical mechanisms that lead to corrosion, and thus contrast them with important variables that have a significant effect on corrosion. According to [PERSON] et al.