Selecting a Technique for Corrosion Monitoring

Many techniques have been used for corrosion monitoring (see Table 8.1), it is clearly possible to develop others. Consequently, when a possible new application is being considered, a problem arises in choosing the most appropriate technique. Each has its strong points and its limitations, and none 

Any monitoring technique can provide only a limited amount of information, and the techniques should be regarded as complementary rather than competitive. Where more than one technique will give the information required, the information is obtained in different ways a cross-check can be valuable and differences in detail can add meaning. 

A corrosion monitoring technique rarely gives wrong information, unless the equipment used is faulty. Nonsense results arise because the information is correct, but irrelevant in the corrosion sense. The polarization resistance method, for example, measures the combined rate of any electrochemical reactions at the surface of the test sample. If the main reactions are corrosion, the rate measured is the corrosion rate. If however, other reactions are possible at rates that are comparable or greater, the measured rate includes the other reactions. 

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