## 3 Results and Discussion
### Analysis of the Laws of Charge Transfer during Polarization
Higher values of the Tafel's coefficient (1/_b_) for cathode sites in 0.5 mol/L magnesium sulfate solutions characterized particle transfer with a smaller value of the activated jump distance. In sodium sulfate solutions, this difference was not significant compared to the experimental spreading. The sharp change in the shape of the curves after half an hour of corrosion after the linear site on the dependences of 1/_b_ to time is also drawn the attention. In this area, the Tafel's coefficient values for cathode and anode polarization began to converge dramatically and their practical matching after the one-hour corrosion became noticeable. Such behavior indicates the transformations in the film resulting in the identity of charge transfer therein in the cathode and anode processes, while there was a marked difference in the initial sites. According to SEM images for half an hour of corrosion, the surface was almost completely covered with the crystalline layer of the second product, but this did not allow to explain the change transfer parameters in cathode and anode polarization. As the Tafel's coefficient (1/_b_) determined in this experiment was a value proportional to the film thickness, it was noticed that the effective film thickness in sodium sulfate solutions decreased while for magnesium sulfate increased. The dependences of the polarization resistance of the magnesium electrode with the film in sodium sulfate solution presented in Figure 6c also confirmed the film resistance reduction. The polarization resistance, which in this case was the film resistance, was calculated from the initial site of the polarization curve (10-20 mV). The same as on the dependence curves of the Tafel's coefficient on time the fact of convergence and stabilization of the film resistance on magnesium in magnesium and sodium sulfate solutions after 100 min of corrosion attracts itself the attention, when the rates of their change are markedly slowed down and the values themselves are converged, demonstrating a movement towards independence from the nature of the electrolyte. This is also perfectly confirmed by the dependence of the magnesium electrode potential on time, which also passes through the acute maximum during the first half hour, and after 100 min, it does not depend on the composition of the solution, demonstrating the identity of the state in different solutions. The positive displacement of the potential of the magnesium electrode during corrosion characterizes the passivation of the surface by the corrosion film. The negative shift in the first 15 min of the magnesium potential of 0.5 mol/L MgSO\({}_{4}\) coincides with the trend of increasing film cracking in this time interval (Figure 1). The same interpretation of the potential shift in the negative direction, due to the introduction of an additive into the electrolyte that dissolves the oxide part of the film, is presented in [27]. A negligible period of the film growth under parabolic law ended with its transformation into another state, where parameters of cathode and anode process transfer were equalized. The most likely variant of such a conversion was the hydration of the primary film's magnesium oxide and its conversion to hydroxide. The general perception is that the characteristics of charge transfer through the film were solely determined by its dense part, which included only the part adjacent to the metal, initially consisting of magnesium oxide and possibly a dense part of the amorphous hydroxide layer. The layers lying above had an incoherent morphology and little determine polarization. That is why there was observed a strong change of electrical characteristics during the initial period of time and the formation of the similar final product over time. Similar regularities of behavior were demonstrated by the concentration dependence of corrosion parameters in magnesium sulfate solutions (Figure 7).