Deposition of Cerium(III)-chloride heptahydrate on Aluminium Alloy 2024-T3 in Chloride Solution

In the present work the corrosion protection of aluminium alloy AA2024-T3 has been studied in chloride solution with and without addition of cerium (III) chloride heptahydrate (CeCl3 X 7H2O). Inhibition efficiency as a function of concentration, temperature and exposure period of immersion (240 h) into 0.01 M NaCl, containing 3 mM, 4 mM and 5 mM of CeCl3 X 7H2O, are investigated at 20 °C, 40 °C and 60 °C. Quantitative tests performed include electrochemical techniques, such as method of quasi-potentiostatic polarization (Tafel extrapolation) to determine corrosion current density (jcorr), inhibition efficiency (η), and degree of surface coverage (ϑ). The kinetic and thermodynamic parameters of adsorption process, such as activation energy (EA), enthalpy of activation (ΔHa0), entropy of activation (ΔSa0), standard adsorption enthalpy (ΔHads0), standard adsorption entropy (ΔSads0) and the adsorption free energy (ΔGads0) were also determined. Adsorption of the cerium ions on the AA2024-T3 surface follows the Langmuir isotherm model.