Corrosion Inhibition Properties of Thiazolidinedione Derivatives for Copper in 3.5 wt.% NaCl Medium

Copper is the third-most-produced metal globally due to its exceptional mechanical and thermal properties, among others. However, it suffers serious dissolution issues when exposed to corrosive mediums. Herein, two thiazolidinedione derivatives, namely, (Z)-5-(4-methylbenzylidene)thiazolidine-2,4-dione (MTZD) and (Z)-3-allyl-5-(4-methylbenzylidene)thiazolidine-2,4-dione (ATZD), were synthesized and applied for corrosion protection of copper in 3.5 wt.% NaCl medium. The corrosion inhibition performance of tested compounds was evaluated at different experimental conditions using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization curves (PPC) and atomic force microscopy (AFM). EIS results revealed that the addition of studied inhibitors limited the dissolution of copper in NaCl solution, leading to a high polarization resistance compared with the blank solution. In addition, PPC suggested that tested compounds had a mixed-type effect, decreasing anodic and cathodic corrosion reactions. Moreover, surface characterization by AFM indicated a significant decrease in surface roughness of copper after the addition of inhibitors. Outcomes from the present study suggest that ATZD (IE% = 96%) outperforms MTZD (IE% = 90%) slightly, due to the presence of additional –C3H5 unit (–CH2–CH = CH2) in the molecular scaffold of MTZD.