CORROSION AND PROTECTION OF CARBON-STEEL IN LOW ENTHALPY GEOTHERMAL FLUIDS - THE CASE OF SOUSAKI IN GREECE

This experimental work is aimed at evaluating first. the effect of a s olution simulating the geothermal fluid of the field in Sousaki, New K orinthia, on the corrosion of bare steel, and, second, the protective performance that certain combinations of organic coatings provide. Thi s evaluation resulted from corrosion potential measurements, mass loss measurements, corrosion rate estimates by the Tafel method, and visua l ranking of the degree of rusting and blistering. Six combinations of organic coatings were tested. Four of them consisted of water-based p aints as primer, as well as intermediate and topcoat. Of the two remai ning combinations, the first comprised a water-based primer, including dispersed tannin and a two-component epoxy resin topcoat, while the s econd consisted of a two-component acrylic primer, containing chromate pigments and the same epoxy resin topcoat as above. All coating combi nations tested exhibited protective performance. The results of the wa ter-based coatings were less satisfactory than those of the two combin ations containing the epoxy resin topcoat. (C) 1997 CNR.