Enhanced corrosion inhibition of copper in acidic environment by cathodic control of interface formation with 2-mercaptobenzothiazole.

• Corrosion inhibition and interfacial bonding of 2-MBT studied on copper. • Electrochemistry combined with advanced surface analysis by XPS and ToF-SIMS. • Inhibition enhanced by cathodic reduction of interface before 2-MBT adsorption. • 2-MBT bonded to metallic copper and copper oxide islands via the S atoms. • Exo- and endocyclic S atoms released by dissociation and bonded to metallic Cu. Electrochemistry along with advanced surface analyzes (X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry) were implemented to investigate copper corrosion inhibition by 2-mercaptobenzothiazole (2-MBT) in hydrochloric aqueous solution and the effects of electrochemical control on the formation of the inhibiting interface. It is shown that reducing the native surface oxide by cathodic reduction prior to exposure to the inhibitor drastically decreases the rate of anodic dissolution. Additionally, increasing the exposure time of the metal surface to the inhibitor results in even better protection against dissolution. 2-MBT adsorbs as multilayers and bonds to both metallic copper and residual copper oxide islands via its sulphur atoms. Partial dissociation of the molecule, releasing the exocyclic sulphur, which then bonds to metallic Cu, is observed. Further dissociation of the molecule, releasing the endocyclic sulphur, is induced by anodic polarization, forming defects in the organic layer and thus compromising the barrier properties of the organic layer. [ABSTRACT FROM AUTHOR]