MONITORING OF BLISTERING OF ORGANIC COATINGS BY A CONTACT-FREE MEASUREMENT

A new technique is presented, which is able to detect corroding parts of a metal surface below technical polymer coatings. The technique (vibrating reference electrode) is based on the observation, that the local corrosion potential - which in turn is given by the rates of the anodic and cathodic partial reactions of the corrosion process - is quite different for an intact and for a delaminated metal/polymer interface. In this paper two different coatings are analysed, which are used in technical flue gas desulfurisation (FGD) plants. It is shown, that the different stability of the two coatings can clearly be elucidated by mapping the corrosion potential of the surface in a humid atmosphere.