Effect of initial CaCO<sub>3</sub> saturation levels on the CO<sub>2</sub> corrosion of 1Cr carbon steel
Riccardo Rizzo, Rajan Ambat
Abstract
Abstract This paper presents the investigation on the effect of calcium on the corrosion behavior of 1Cr carbon steel under various levels of initial CaCO 3 saturation ( ) of the bulk solutions. All the experiments were performed at 80°C in 1 wt% aqueous NaCl solution saturated with CO 2 . Four initial levels were investigated, namely 0, 0.6, 2, and 10. The corrosion process was followed using linear polarization resistance, potentiodynamic sweeps, and electrochemical impedance spectroscopy. The surface morphology of the corrosion products was analyzed with scanning electron microscopy and structural information using X‐ray powder diffraction. Precipitation of a substitutional solid solution of Fe x Ca y CO 3 ( x + y = 1) was found on the steel surface. The growth of this layer was delayed by Ca 2+ ions in the solution, but its protectiveness was not affected and was comparable with the pure FeCO 3 corrosion product. No signs of localized corrosion were detected on the material.