Electrochemical Techniques for Predicting Galvanic Corrosion

Abstract

The various electrochemical techniques for predicting galvanic corrosion behavior of metals are described. Each method is evaluated on the basis of practicality using specific galvanic couples as examples. The paper describes some serious shortcomings of the existing techniques and warns of the dangers of their improper use.

Practical Corrosion Prediction Using Electrochemical Techniques

“…The effect of fluid velocity was examined by coupling the EIS measurement with a rotating-cylinder electrode and estimating polarization resistance as a function of rotation rate. 1  10 2 (2.5) 10 3 1  10 (0.25) 10 4 1 (0.025) 10 5 l  10 À 1 (0.0025) 10 6 1  10 À 2 (0.00025) 10 7 1  10 À 3 (0.000025) corrosion rates were estimated by assuming a proportionality constant of 0.025 V between the polarization resistance and the corrosion current because of difficulties in estimating reasonable Tafel slopes under the dynamic conditions in these complex systems. The time-averaged corrosion rate was compared to that estimated from mass loss of the electrode.…”

“…The best approach is to apply several independent techniques, some of which may be nonelectrochemical, to the same problem. Thermodynamics, various electrochemical techniques, theoretical calculations, various types of spectroscopies, and traditional coupon immersion tests have been combined to provide the insights needed to make reliable corrosion predictions [1][2][3][4].…”

Galvanic Corrosion between Nonmetallic Composites and Metals II. Effect of Area Ratio and Environmental Degradation

“…The test cell adopted in this paper is similar to that reported in the literature. 2 A description of it is omitted for simplicity. Before each experiment, the surface of the metallic electrode was cleaned with a fine emery paper, rinsed in distilled water, degreased in acetone, dried in an air stream, and weighed.…”

Fundamentals and applications of laser-optical interferometry as electromagnetic tools for materials evaluation in complex medias

“…But the most significant parameter for this investigation is the polarization resistance of the carbon steel samples in different solutions of seawater. This is because from the polarization resistance values, the corrosion current density can be determined from the linear polarization method [4] . It is worth mentioning that in each experiment, the holographic interferograms were recorded as a function of time, in which each test lasted for less than 30 minutes, the duration of the A.C. impedance test.…”