Inhibition mechanism of self-assembled epoxy-silane/dithiol film on copper corrosion

Inhibition effects of an γ-(2,3-epoxypropoxy) propyl-trimethoxy-silane (abbreviated as epoxy-silane) and 3,6-Dioxa-1,8-octanedithiol (abbreviated as DOT) film on copper corrosion in 3.5 wt% NaCl solution were studied by digital hsolography, electrochemical methods and surface characterization approaches. In-situ observation of the concentration change at the electrode/electrolyte interface during dynamic potential scan by holography revealed that the dissolution of copper was inhibited significantly and no CuCl film formation was found on the surface of the modified film. Sputtering measurements by X-ray photoelectron spectroscopy showed that some Cl − ions permeated into the outer layer of the epoxy-silane/DOT film and formed CuCl interlayer with the Cu + ions in the film. The CuCl interlayer in the modified film blocked its micropores, inhibiting the copper corrosion. The initial electro-dissolution reactions on bare copper and modified copper have been discussed accordingly. The study proved the digital holography to be an effective method to evaluate anti-corrosion performance and elucidate the related mechanisms in particularly.