Rotated cage corrosion experiments (4 m/s) were performed with flat coupons of 2 carbon steels
(38Mn6/C75, X65) and 3 corrosion resistant alloys [X20Cr13, X2CrNiMoN22-5-3 (1.4462, duplex)
and X1NiCrMoCu 25-20-5 (1.4539; alloy 904L)] in water saturated with CO2 under conditions of
supercritical carbon dioxide (scCO2). In this corrosion system the performance of inhibitors (oleic acidbased
imidazolines, alkenylsuccinic acid anhydrides, and quaternary ammonium salts) was studied at 50,
80, 110 and 130oC using mass loss measurements and topographical scanning (in case of localized
attack). The corrosion inhibitors applied proved to be effective not only for the carbon steels but also for
the corrosion resistant alloys (CRAs). Maximum corrosion rates of CRAs encountered at 110°C in the
absence of inhibitors (13 Cr steel: 0.3-0.8 mm/y; duplex steel: >0.1 mm/y; austenitic CrNi steel >0.1
mm/y) could be reduced with inhibitors to very low corrosion intensities (< 0.04 mm/y). However, none
of the inhibitors could reduce the corrosion rates of carbon steels below 1 mm/y.
Keywords: carbon steels, X65, 13 Cr steel, duplex steel, austenitic CrNi steel, water; corrosion,
supercritical carbon dioxide, rotated cage, inhibitors,