Effect of Compounded Inhibitor on the Electrochemical Behaviour of 2024 Aluminum Alloy after Severe Plastic Deformation in the Ambient Corrosive Aquous Solution

Similar welds composed of 2024 alloy were fabricated by friction stir welding (FSW). In the ambient aqueous solution of 0.2 mol/L NaHSO3 + 0.6 mol/L NaCl + 0.004 mol/L Na2MoO4, with the compounding of different concentrations of thiourea, by potentiodynamic polarization curve tests and electrochemical impedance spectroscopy (EIS). The synergism of inhibitors on the corrosion behaviors of the friction stir welds (FSW) and 2024 were comparatively investigated. The results indicate that in the solution of 0.2 mol/L NaHSO3+ 0.6 mol/L NaCl + 0.004 mol/L Na2MoO4 with 0.040 mol/L CH4N2S, the polarization resistance R-p of 2024 alloy and weld is maximum, and inhibition efficiency is optimal. Meanwhile, the inhibition efficiency of the weld is superior to that of 2024 alloy at the given concentration of thiourea. This shows that the specific adsorption ability for the weld is better than that for 2024 alloy A probable mechanism is presented to explain the experimental results.