Corrosion Inhibition of Brass in Industrial Cooling Water Systems
Florina Branzoi *
Department of Electrochemistry and Corrosion, Institute of Physical Chemistry, 202 Splaiul Independenţei, Bucharest, Romania
Viorel Branzoi
Department of Applied Physical Chemistry and Electrochemistry, University Politehnica of Bucharest, 132 Calea Griviţei, Bucharest, Romania
*Author to whom correspondence should be addressed.
Abstract
The inhibitory effect of PASAC1, PASAC 11 and PASAC13 on the corrosion behavior of brass in cooling water system at temperature of 25°C was studied by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), FTIR spectroscopy and metallurgical microscopy techniques. In the present paper, three types of organic inhibitors obtained by radicalic polymerization, i.e., PASAC1 (urea and maleic anhydride at molar rapport 1:1.5 at temperature of 140°C), PASAC 11 (polyaspartic acid and H3PO4 molar ratio 1:0.05 at temperature of 170°C), PASAC13 (polyaspartic acid 0.07 M and H3PO4, gravimetric ratio 1/1.5 with trisodium citrate at temperature of 200°C) was selected. The result of these polymers concentration on inhibition efficiency, the corrosion rate and surface coverage is investigated. Results show that these organic inhibitors exert a strong inhibiting effect on brass corrosion and acts as a mix-type inhibitor. The inhibition efficiency of organic polymers may be due to either the adsorption of inhibitor molecules building a protective film or the formation of an insoluble complex of the inhibitor adsorption obeys the Langmuir model. Further, characterization using FT-IR demonstrates the adsorption of organic inhibitors and the development of corrosion compounds at brass surface. EIS results confirm its corrosion inhibition ability.
Keywords: Organic inhibitor, brass, cooling water, electrochemical techniques;, EIS and FT-IR.