Coatings are widely applied to improve the durability of components. In order to understand
how corrosion protection is obtained, the behaviour of coatings in aggressive environments
must be characterized. Factors responsible for an increase of the susceptibility to corrosion
are indentified and methods available to characterize these factors are reviewed. These are
indirect methods as they do not concern the measurement of corrosion rates, nor the study of
corrosion mechanisms. They deal with morphology, composition, crystallographic structure
and mechanical properties of the coating.