AcCELERATED TESTS, A NECESSARY COMPLEMENT OF eLECTROCHEMICAL ASSAYS TO EVALUATE ANTICORROSION cOATINGS

O. D'ALESSANDRO; G. J. SELMI; R. ROMAGNOLI; M. C. DEYA

Cusco

Congreso; SIBAE; 2018

Sociedad iberoamericana de electroquímica

Corrosion processes may be monitored by accelerated and/or electrochemical assays. There is certain relationship between both types of test. Particularly, in the case of coatings with a high barrier effect (R > 108 Ω.cm2) and a low paint film capacitance (C < 10-9 F.cm-2) a good anticorrosion performance was accomplished. Once corrosion has started, a high value of the charge transfer resistance ensures kinetic inhibition of the corrosion process. The question arises when the above mentioned parameters differ from those stipulated values and a realistic evaluation of the coating is needed. In this paper it was demonstrated that, in such cases, accelerated and electrochemical assays complement each other. Accelerated tests relate to coating durability while electrochemical ones provide information about the degradation mechanism. To carry out this investigation three anticorrosion paints containing ecological pigments were prepared and subjected to the salt spray chamber and electrochemical impedance measurements.