Abstract
Preliminary work has investigated the roles of the barrier properties and the metal/coating interface in the corrosion protection properties of fluoropolymer coatings. In particular, the water barrier properties and their effect on the degradation of the interface (corrosion and loss of adhesion) have been studied. The coatings used were unpigmented fluoropolymer based paints with good barrier properties in relation to ions and water, but weak adhesion properties, and the main investigation techniques used were electrochemical impedance spectroscopy and adhesion pulloff tests. Electrochemical and adhesion results show a clear influence of water uptake on the degradation of adhesion and corrosion protection properties of the organic coating, with increase of mobility of aggressive ions, i.e. chlorides, through the coating. A comparison of results shows interesting differences between the classes of materials studied. The reversibility of the water uptake process has also been studied and shows the presence of permanent effects of the water uptake process on the barrier properties of the paint, which remained less protective even after complete water desorption
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