EVALUATION OF DETERIORATION OF ORGANIC COATED STEELS IN CO2 ABSORPTION PROCESS BY ELECTROCHEMICAL MEASUREMENT METHODS

The deterioration of polymeric resins for corrosion protection, such a s polyvinyl chloride (PVC), polyurethane (PUR), thick film of epoxy re sin containing the coloring pigments such as titanium dioxide (EP-P) a nd clear epoxy resin (EP-C), was evaluated by electrochemical impedanc e spectroscopy (EIS) and scanning vibrating electrode technique (SVET) in a CO2 absorption process environment. In this experimental system, the correlation between the film resistance (Rf) and film capacitance (C-f) was obtained from EIS measurements, and visual observation. Als o, a significant correlation was observed between the lifetime of pain t film (t(s)) obtained from EIS measurements and visual observation, a nd the current density (i) from SVET. From the experimental results, i t was proved that the corrosiveness of these coated steels in the aque ous solution of potassium carbonate was greatly dependent on the absor ption of CO2, and the more the absorption abounds, the stronger the co rrosiveness observed. (C) 1995 Elsevier Science S.A.