Anthocyanins as a corrosion inhibitor for 2024-T3 aluminum alloys: A study of electrochemical behavior

Abstract

Grape anthocyanin efficiency as a corrosion inhibitor for 2024-T3 aluminum alloy was evaluated by electrochemical techniques such as, electrochemical impedance spectroscopy and cathodic and anodic potentiodynamic polarization. The inhibitor behavior for 2024-T3 aluminum alloy was investigated in 800, 1000, 2000, 3000, 5000 and 7200 ppm of the grape anthocyanin solution in the presence of 0.025 mol·L-1 NaCl. According to electrochemical impedance spectroscopy results, the measured point dispersion in the low frequencies region decreased when the 2024-T3 aluminum alloy immersion time in the grape anthocyanin solution increased from 1 h to 3 days. It was also observed for samples after 3 days immersion that there was a reduction in the inductive behavior in the same region, and a considerable increase in the polarization resistance and inhibition efficiency for the 1000 ppm grape anthocyanin sample. Under anodic and cathodic polarization a generally better performance was also observed in the anticorrosive properties as potential and current corrosion and anti-corrosion protection efficiency for the above mentioned concentration sample. The grape anthocyanin adsorption characteristics, on the AA2024-T3 indicated similar behavior to Langmuir isotherm.