Characterization of copper and brass surfaces in chlorinated tap water using phosphate ions as green corrosion inhibitor.

L.YOHAI; W. SCHREINER; M. VAZQUEZ; VALCARCE, M. B

Florianopolis

Simposio; 10th Intl. Symposium on Passivity of Metals and Semiconductors; 2011

In previous work it has been demonstrated that the corrosion behavior of copper and brass improves in the presence of phosphate ions, particularly when they are in contact with a moderately hard, highly carbonated and chloride-rich drinking water. A decrease in the copper cuprosolvency together with an increment in the pitting resistance, have been related to changes in the passive films on both materials. When PO43- is added as corrosion inhibitor, the film, becomes thinner, denser and more compact, and also changes its composition 1, 2. In addition, the efficiency of this inhibitor has been evaluated in the presence of NaOCl, the most commonly used biocide in drinking water 3. When the inhibitor is added to ATW + NaClO, weight-loss tests showed that generalized dissolution is inhibited on copper and brass. Brass presented pitting in ATW and dezincification in ATW + NaClO, but the presence of phosphate ions was able to inhibit both types of localized attack.