Electrochemical and gravimetric study on the corrosion and corrosion inhibition of pure copper in sodium chloride solutions by two azole derivatives

Abstract

The objective of this work was to investigate the corrosion and corrosion inhibition of 99.999% purity copper in sodium chloride (3.5% NaCl) solutions by 3-amino-5-mercapto-1,2,4-triazole (AMTA) and 5-(3-Aminophenyl)-tetrazole (APTA). Corrosion inhibition was studied using a variety of electrochemical tests and gravimetric and pH measurements. The polarization curves showed that the presence of either AMTA or APTA successfully reduced the corrosion of copper and this effect increased with increasing the compounds' concentration. Chronoamperometric experiments indicated that the highest currents for copper were recorded in 3.5% NaCl alone, while the presence of inhibitors highly decreased the dissolution currents. Electrochemical impedance spectroscopy revealed that the presence of inhibitors remarkably increased the impedance of copper over the whole studied frequency range. Gravimetric experiments showed that the dissolution rate and pH of the solution decreased to a minimum after 24 days of copper immersion due to the presence of the organic compounds. Both electrochemical and gravimetric data confirmed that the presence of inhibitors decreases the corrosion rate and increases corrosion resistance for copper in 3.5% NaCl solutions. © 2012 by ESG.