An electrochemical and X-ray computed tomography investigation of the effect of temperature on CO2 corrosion of 1Cr carbon steel

This paper presents the investigation on the effect of temperature on the corrosion behavior of 1Cr carbon steel at 40 degrees C and 80 degrees C in 1 wt. % NaCl aqueous solution saturated with CO2. The evolution of the corrosion process was followed with Linear Polarization Resistance (LPR) and Electrochemical Impedance Spectroscopy (EIS). Xray Computed Tomography was used for 3D structure of the scale ex-situ to correlate with electrochemical investigation. Additionally, the surface morphology of the corrosion products was analyzed with Scanning Electron Microscopy (SEM) and structural information using X-ray powder diffraction (XRD). Tomography results showed protective FeCO3 formation with three different layers at 80 degrees C, where corrosion underneath the scale was uniform. The 3D image of the corrosion products formed at 40 degrees C showed loose and porous, and consequently did not reduce the corrosion rate unlike for 80 degrees C. Low temperature test also showed signs of localized corrosion beneath the corrosion products.