Test programs can provide useful information for a variety of tasks such as the development of new materials and coatings, the choice of protective schemes for new and old equipment. Test methods for determining corrosion resistance are specific and must be based on conditions prevailing in certain environments and applications. A large number of factors affect corrosion behavior, and therefore there is no universal corrosion test. The most reliable indication of corrosion behavior is service history. However, that information is rarely available exactly as needed, and therefore other tests are required, ranging from simple field trials to highly accelerated laboratory tests. It is the need to obtain information outside of service history that introduces ambiguity in corrosion testing.
In order to quantify the corrosion resistance of a material, it is common practice to submit the material to harsher environments than normally encountered in service, hoping to accelerate the damage. Alternatively, a corroded surface and the corrosion products formed during normal exposure can be studied with very sensitive surface analysis techniques, hoping to amplify the visibility and characteristics of the damage. Since most corrosion processes occur at the metal/environment interface, much progress in the study of corrosion mechanisms can be related to the gigantic advances made in surface analysis techniques. In fact, scientists involved in the study of fundamental processes of corrosion have often been the first to explore the application of new surface analysis techniques to materials engineering problems.