The corrosion inhibition effect of sodium silicate and Triton X-100 on 2024-T3 aluminum alloy in NaOH medium: Experimental and theoretical research

Abstract

The corrosion inhibition performances of Triton X-100 (TX-100), sodium silicate (Na2SiO3) and their mixture for aluminum alloy in 0.01 mol·L−1 NaOH solution were investigated by weight loss methods, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and Fourier transform infrared (FTIR). The corrosion inhibition mechanism was explored by quantum chemical calculation and molecular dynamics simulation. From the results of tests, it was shown that the inhibition efficiency of TX-100 was about 44.03 % at concentration of 0.01 mol·L−1. And the inhibition efficiency reached about 85.84% when the mixture of TX-100 and Na2SiO3 at the same concentration 0.005 mol·L−1. The inhibition efficiency of Na2SiO3 was 97.23 % at 0.01 mol·L−1 due to the coating formation by higher aggregates silicates, which was different from mechanism of traditional inhibitor. Quantum chemical calculations manifested that SiO32− had a smaller energy gap (ΔE) than TX-100. The adsorption energy results of molecular dynamics simulation were consistent with the experimental results. The corrosion inhibition mechanism of the protective layers was also discussed by experimental methods and verified by theoretical research.