Co-effect of bis(cyclohexanone) oxalyldihydrazone and copper(II) ion on the corrosion of cold rolled steel in 0.5 M hydrochloric acid solution

✍ Scribed by Q. Qu; G. Gao; H. Guo; L. Li; Z. Ding

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: German
• Weight: 680 KB
• Volume: 62
• Category: Article
• ISSN: 0947-5117
• DOI: 10.1002/maco.200905522

✦ Synopsis

Abstract

Effects of bis(cyclohexanone) oxalyldihydrazone (BCO) and copper(II) ion (Cu^2+^) on the corrosion of cold rolled steel (CRS) in 0.5 M hydrochloric acid (HCl) solution were investigated using Tafel polarization curve and electrochemical impedance spectroscopy (EIS) at 20 °C. Results elucidate that the inhibition efficiency increases with increase in BCO concentration, and the addition of 10^−5^ M Cu^2+^ significantly enhances the inhibition efficiency of BCO. Polarization curve results elucidate that the single BCO acts as a mixed‐type inhibitor while the combination of Cu^2+^ and BCO acts as cathodic inhibitor. Ultraviolet and visible spectrophotometer (UV–Vis) results show that BCO molecules do not interact with Cu^2+^ and Fe^2+^ in 0.5 M HCl solution. Atomic force microscope (AFM) result indicates that a protective layer forms on CRS surface after immersion in 0.5 M HCl containing BCO in the absence and presence of Cu^2+^. The adsorption of BCO is found to follow the Langmuir adsorption isotherm in the presence and absence of Cu^2+^. The mechanism of typically chemical adsorption is proposed via the value of free energy of adsorption (ΔG) in the presence of BCO and Cu^2+^.