Electrochemical Investigation on Crevice Corrosion of P110 Steel by Using One-Dimensional Array Electrode

In order to understand the corrosion damage to the inner contact surface of screw thread joint between tubing and coupling, artificial crevice was built by one-dimensional array electrode. Potentiodynamic polarization (PDP) technique, electrochemical impedance spectroscopy (EIS), scanning electrochemical microscopy (SECM) and scanning electron microscope (SEM) were adapted to measure the electrochemical behavior for each array electrode at different sites in the crevice. The obvious crevice corrosion was found for P110 oil tube steel in the CO2 dissolved brine solution. The blockout effect inhibits carbonic species adsorbing to steel and produces low pH, which elevates corrosion in the neighboring region to the occluded area. A multi-staged model for the crevice corrosion was proposed.