The corrosion behavior of A106 carbon steel in piperazine, an advanced alternative postcombustion CO2 capture solvent to monoethanolamine, has been investigated. Electrochemical corrosion testing methods such as linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS) have been used to evaluate the corrosion of A106 in 0.43 mol CO2/mol alkalinity (C/N) loaded 30 wt % piperazine at 80 degrees C for 150 h. In addition, immersion corrosion has been carried out up to 1050 h in a traditional corrosion cell with the same CO2 loaded solution but at 100 degrees C and 110 psi. Subsequently, as-corroded A106 samples were characterized by scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) and X-ray diffraction (XRD). The results showed that a sharp decrease in the corrosion rate occurred before reaching a steady-state corrosion process. This was due to the growth of a protective and stable layer of FeCO3. Possible mechanisms are discussed.