Electrochemical behaviour of brass in artificial seawater: effect of organic inhibitors

The electrochemical behaviour of brass was studied in artificial seawater with two organic inhibitors namely N,N-dibenzotriazol-1-ylmethylaminomethane (DBMM) and 3-hydroxypropyl benzotriazole (HPBT) using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), cyclic voltammetry and current transient techniques. Preliminary screening of the inhibition efficiency (IE) was carried out using weight-loss measurements. Polarization measurements showed that the organic compounds investigated are mixed type inhibitors, inhibiting the corrosion of brass by blocking the active sites of the metal surface. Changes in the impedance parameters (charge transfer resistance (R-ct) and double layer capacitance (C-dl)) are related to adsorption of organic inhibitors on the metal surface, leading to the formation of a protective film, which grows with increasing exposure time. Cyclic voltammetric studies confirmed that the addition of inhibitors effectively inhibits the anodic dissolution of brass in artificial seawater. (C) 2004 Elsevier B.V. All rights reserved.