Corrosion behavior of thermal sprayed carbide cermet coating in an alkaline aqueous solution that was exposed to air and aerated was examined by electrochemical processes. In this study, the galvanic corrosion due to contact with under-coating or substrate was considered. The results obtained are following:(1) Anodic polarization of thermal sprayed Cr3C2/NiCr coating indicates active dissolution. The NiCr matrix may have major influence on it.(2) The corrosion rate of thermal sprayed NiP under-coating tends to be faster than that of carbon steel.(3) Chloride ions in 1M·NaOH solution may have minor influence on the corrosion behavior of thermal sprayed Cr3C2/NiCr and NiP coatings and carbon steel.