The condition of corrosion in a concrete or metal element is determined through electrochemical corrosion testing. Electrochemical corrosion testing, which is based on electrochemical theory, evaluates corrosion damage and, when possible, determines corrosion rates. All corrosion is an electrochemical reaction involving oxidation and reduction. To assess the corrosion characteristics of metals and metal components in conjunction with various electrolyte solutions or soil conditions, controlled electrochemical experimental approaches can be utilised. Each metal/solution system has its own corrosion properties. Matergenics conducts electrochemical tests to assess or forecast metal corrosion rates in a variety of situations. The ASTM/NACE methods, Cyclic Polarization, Impedance Spectroscopy, linear polarisation tests, electrochemical testing for hydrogen permeation, real-time corrosion forecasts for materials, and others are among the electrochemical techniques.
Some Electrochemical testing involves –
1 Linear Polarization Resistance (LPR)
A very common and simple electrochemical corrosion test is LPR. In this test, when the applied potential scans in a restricted range (20 mV) from lower to higher than the corrosion potential, the current is monitored (Ecorr). The polarisation resistance, which is inversely related to the corrosion rate, is shown by the slope of the current against potential curve. This test is quick and easy to perform, and it is commonly regarded as a non-destructive test. Furthermore, this approach is particularly good for determining extremely low corrosion rates. The slope of the line shows polarization resistance(Rp).
2 Cyclic Potentiodynamic Polarization
CPDP is used to determine the resistance to localized corrosion or degradation rate in a short time. In this test, the sweeping direction of applied potential is reversed at some potential in the transpassive region. The intersection between forward and backward scans shows the tendency and intensity of localized corrosion.
3 Electrochemical Potentiodynamic Reactivation (EPR)
Electrochemical potentiodynamic reactivation (EPR) is a type of test created to evaluate susceptibility to intergranular or non-uniform corrosion. An advantage of EPR is that it makes on-site, nondestructive examination possible. EPR is a technique involving specimen polarization that is used for evaluating corrosion rates. It is a widely used method wherein the electrode potential varies on a particular rate through current application via the electrolyte. It utilizes potentiodynamic sweeps throughout potentials, such as from passive into active potential, also known as reactivation.
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