Effect of Microstructure on Corrosion of Steels in Aqueous Solutions Containing Carbon Dioxide

An In Situ Synchrotron Radiation Grazing Incidence X-Ray Diffraction Study of Carbon Dioxide Corrosion

“…Clearly, the products of the carbon dioxide corrosion of mild steel are more stable to air than previously thought, and the results of ex situ surface analyses, such as those of Al-Hassan et al, 7 appear to be credible and reliable, despite the perceived uncertainty of the aerial oxidation of the corrosion product on exposure to air.…”

“…For chromium steels, Al-Hassan et al 7 have identified the formation of Fe 2 ͑OH͒ 2 CO 3 above 60°C. This phase would explain many of the apparent anomalies that have been ascribed, possibly incorrectly, to the aerial oxidation of iron carbonate in ex situ surface studies.…”

“…[3][4][5] Nevertheless, ex situ X-ray diffraction ͑XRD͒ studies have identified siderite ͑FeCO 3 ͒ as the primary corrosion product on mild steel substrates subjected to carbon dioxide corrosion. 6,7 Previous ex situ X-ray photoelectron spectroscopy ͑XPS͒ and in situ surface-enhanced Raman spectroscopy ͑SERS͒ 8,9 have also identified iron oxides/iron hydroxides/iron carbonates on a mild steel substrate electrode subjected to carbon dioxide corrosion. The detection of iron oxides/iron hydroxides in these ex situ XPS experiments inferred that aerial oxidation of the iron carbonate corrosion product, following removal of the specimen from solution, is the cause of an oxygen/water-induced oxidative/hydrolytic decomposition of the corrosion scale.…”

Analysis of the corrosion scales formed on API 5L X70 and X80 steel pipe in the presence of CO2

“…These differences affect not only the mechanical properties of the steel but also its corrosion rate 4,12,17 . The literature indicates that growth of an FeCO 3 film is facilitated in steels with a ferrite-pearlite structure due to better anchorage of the carbonate deposits which adhere to the metal surface 5,[23][24][25][26] . The explanation is based on the fact that ferrite located within the pearlitic matrix is dissolved and the deposit of carbonate is thus anchored between the remaining plates of cementite exposed at the surface.…”

Corrosion in the Oil and Gas Industry: An Increasing Challenge for Materials

“…53 The effect of the microstructure of LAS on CO 2 corrosion has been widely studied, but many issues are still uncertain and contradictory results can be found in the literature. [54][55][56][57][58][59] Regarding the effect of steel composition, the positive influence of low Cr additions ($3%) on CO 2 corrosion performance of standard carbon steel is reported in the literature. 60,61 Energy-dispersive x-ray and Fourier transform infrared analysis showed that chromium-enriched surface films (iron/ chromium oxy-hydroxides) are formed during the corrosion process causing a corrosion rate reduction.…”