Corrosion refers to a process that involves deterioration or degradation of metal. The most common example of corrosion is the degradation of metals or alloys.
Most corrosion phenomena are electrochemical in nature and consist of at least two reactions on the surface of the corroding metal. One of the reactions is the oxidation (e.g., dissolution of iron), also referred to as the anodic partial reaction. The other is a reduction reaction (e.g., reduction of oxygen), and is referred to as the cathodic partial reaction.
The products of the electrochemical reactions can react chemically with each other to form the final product (e.g., rust).
Measurement of Corrosion Rates
The simplest way of measuring the corrosion rate of a metal is to expose the sample to the test medium (e.g., sea water) and measure the loss of weight of the material as a function of time. Although these tests are simple, there is no easy way to extrapolate the results to predict the lifetime of the system under investigation. Moreover, some corrosion processes occur with no significant mass change (e.g., pitting corrosion) making them difficult to detect by gravimetric methods.
Electrochemical methods provide an alternative to traditional methods used to determine the rate of corrosion. Direct and quantitative determination of corrosion rates can be determined from simple electrochemical measurement like LSV.
Most corrosion phenomena are electrochemical in nature and consist of reactions on the surface of the corroding metal. Therefore electrochemical tests methods can be used to characterize corrosion mechanisms and predict corrosion rates.
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