Evaluation of corrosion inhibitors for cooling water systems operating at high concentration cycles

• Published in: Materials and corrosion 2009-05, Vol.60 (5), p.323-329
• Main Authors: de Souza, E. A., Ponciano Gomes, J. A. C., Reznik, L. Y., Sathler, L.
• Format: Article
• Language: English
• Subjects: Applied sciences; cooling water; Corrosion; Corrosion environments; corrosion inhibitors; Corrosion prevention; Exact sciences and technology; high concentration cycles; Metals. Metallurgy
• ISSN: 0947-5117; 1521-4176
• DOI: 10.1002/maco.200805098

The present work aimed at evaluating AISI 1020 carbon steel corrosion resistance of a 6:4:1:1 (MoO 42−/HEDP/PO 43−/Zn2+) inhibitor mixture present in a solution which simulates an industrial cooling water system operating at high concentration cycles (1050 ppm Cl− and 450 ppm Ca2+). High concentration cycles are desirable, because system purge and treated water consumption are decreased. On the other hand, a high number of concentration cycles can increase the concentration of salts and dissolved impurities, causing corrosion, incrustations, and deposits inside the pipes, heat exchangers, and cooling towers. Thus, the chloride (Cl−) and calcium (Ca2+) ions aggressiveness was studied on the proposed inhibiting mixture, at the temperatures of 40 and 60 °C, through electrochemical techniques like open circuit potential measurements, anodic and cathodic polarization, and weight loss. The results showed that the inhibitor mixture conferred adequate protection to carbon steel in low concentrations, even in high aggressive media.