The Inhibitive Effect of 3-Methyl 4-Amino 1,2,4 Triazole on the Corrosion of Copper-Nickel 70 - 30 in NaCl 3% Solution

The effect of 3-methyl 4-amino 1,2,4 triazole (MATA) on the corrosion behaviour of copper-nickel 70 - 30 (Monel) in NaCl 3% solution is investigated at 298 K by weight loss measurements, potentiodynamic polarisation and impedance spectroscopy (EIS′) methods. Preliminary screening of the inhibition efficiency (ECR) was carried out with using weight- loss measurements. Polarization measurements showed that the organic compound investigated is mixed type inhibitor (it acts on the cathodic and the cathodic reactions), inhibiting the corrosion of Monel by blocking the active sites of the metal surface. Changes in the impedance parameters charge transfer resistance (Rct) and double layer capacitance (Cdl) are related to adsorption of organic inhibitor of the metal surface, leading to the formation of protective film, which grows with increasing exposure time. Inhibition efficiencies obtained from cathodic Tafel plots, gravimetric and EIS methods are in good agreement. Results obtained shows that the (MATA) is good inhibitor for copper – nickel, and its efficiency reaches more than 95% at 60 ppm after 30 mn of immersion.