Electrochemical study of copper corrosion inhibition in acidic environment by 5-(4'-isopropylbenzylidene)-2,4-dioxotetrahydro-1,3-thiazole

Abstract

Corrosion inhibition properties of the thiazole derivatives, namely (5-(4'-isopropylbenzylidene)-2,4-dioxotetrahydro-1,3-thiazole) (5-IPBDT), as a corrosion inhibitor for copper in acidic sodium sulphate solution 0.1 M have been studied by electrochemical and electro-gravimetrical methods such as potentiodynamic polarization measurements, electrochemical impedance spectroscopy (EIS), electrochemical quartz crystal microbalance (EQCM), and scanning electrochemical microscopy (SECM. The polarization curves showed that the presence of 5-IPBDT successfully reduced the corrosion of copper and this effect increased with increasing the applied concentration. EIS revealed that the presence of inhibitor remarkably increased the impedance of copper electrode over the whole studied frequency range. By obtaining the polarization resistance, the inhibition efficiency of 5-IPBDT as high as 93%, which is in a good agreement with the results obtained by the polarization curves (96%). By using SECM, the formation of the inhibitive film was followed in time. At the open circuit potential, the surface changed gradually from a conductive to an insulating surface in the presence of 5-IPBDT. EQCM studies revealed that the inhibitor shifted the breakdown potential (Eb) of copper electrode to more anodic value, reduced the corrosion current density and hindered the electrode mass loss. Both electrochemical and gravimetric data confirmed that the presence of inhibitor decreases the corrosion rate and thus increases corrosion resistance for copper in 0.1 M Na2SO4solution.