Eco-friendly approach to corrosion inhibition of AA5083 aluminum alloy in HCl solution by the expired Vitamin B1 drugs

Abstract The purpose of present work is to understand the influence of molecular structure of drug on corrosion inhibition properties. Expired Vitamin B1(VB1) containing thiazole ring is first used as eco-friendly inhibitor for AA5083 aluminum alloy in acid medium. The anti-corrosion performance of expired VB1 is estimated by weight loss method, potentiodynamic polarization, impedance measurement and surface analyses. The results indicate that the inhibition efficiency increase with the increase of concentration at different temperatures, and the maximum inhibition efficiency reach 87.85% at 288 K. Electrochemical methods show that VB1 act as a mix-type corrosion inhibitor. The adsorption model of VB1 on the surface of AA5083 obeys Langmuir adsorption isotherm, and the value of the standard Gibbs free energy manifest that VB1 involve a mixed function concerning physisorption and chemisorption. Surface analyses including scanning electron microscopy (SEM), atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS) confirm that VB1 can retard effectively corrosion by adsorption film. Theoretical calculation further reveals the adsorption mechanism of corrosion inhibitor VB1.