Diffusion of iron ions through protective coatings on steel
(EN)
Ragoussis, A
(EN)
Skoulikidis, T
(EN)
Quantitative electron probe microanalysis (EPMA) measurements on the cross section of a polymer or anticorrosive paint coating on steel, exposed to a corrosive environment (3.5% NaCl solution), showed diffusion of iron ions through the coating toward the environment. Quantitative measurements followed to determine the Fe2+ diffusion rates through the coatings for several temperatures and to calculate the activation energy for each type of coating. These values compare with corrosion rates and the activation energies determined from gravimetric measurements (weight loss) obtained under the same conditions. A commercial, anticorrosive paint coal tar epoxy retards this diffusion. These measurements can, in some cases, complement the electrical or weight loss measurements when the anticorrosive properties of coatings on steel exposed in a corrosive environment are tested.
(EN)
