Examples of Applied Electrochemistry to Corrosion

Given the electrochemical nature of corrosion processes it is not surprising to see that measurements and control methods based on electrochemical principles are so extensively used across the whole spectrum of corrosion science and engineering. The following sections provide some examples to illustrate how these principles are applied in practice. 

A potentiod5mamic polarization variant is cyclic voltammetry which involves sweeping the potential in a positive direction until a predetermined value of current or potential is reached, then the scan is reversed toward more negative values until the original value of potential is reached. In some cases, this scan may be done repeatedly to determine changes in the current-potential curve produced with scanning. 

Another variation of potentiodynamic polarization is the potentio-staircase method which refers to a technique for polarizing an electrode in a series of potential steps where the time spent at each potential is constant, while the current is often allowed to stabilize prior to changing the potential to the next step. The step increase may be small, in which case, the technique resembles a potentiodynamic curve [6]. 

Electrochemical potentiodynamic reactivation (EPR) is another polarization method that evaluates the degree of sensitization of stainless steels such as S30400 and S30403 steels. This method uses a potentiodynamic sweep over a range of potentials from passive to active (called reactivation). 

This technique has been especially useful to assess localized corrosion for passivating alloys such as S31600 stainless steel, nickel-based alloys containing chromium, and other alloys such as titanium and zirconium. Though the generation of the polarization scan is simple, its interpretation can be difficult [7]. 

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