Corrosion Testing of Materials with Metallic and Inorganic Coatings

Corrosion resistance is an important characteristic of many types of metallic and inorganic coating systems. Corrosion resistance of coatings usually involves appearance maintenance as well as protection from structural damage. Corrosion tests have been an important approach for evaluating the type and extent of damage that occurs to coated products. Corrosion tests have been used both to assure the quality and performance of coated parts and to simulate the degree of degradation that occurs to components when exposed to specific atmospheric conditions for an extended time. The standard tests that have been developed for both of these purposes are described, and some of the problems with the testing approach are reviewed. In particular, the problem of simulating and accelerating atmospheric corrosion in a laboratory environment is highlighted. Some of the newer approaches to corrosion testing using electrochemical techniques are discussed. These approaches may have merit, but many problems remain to be solved.