The Effect of Salt Composition on the Corrosion of 18Cr12Ni2Mo Stainless Steel in Molten Carbonate

The effect of salt composition on the corrosion rate of 18Cr12Ni2Mo stainless steel has been investigated by corrosion test maintained at constant potential (vs. O2/CO2/Au) and electrochemical measurements in molten carbonate at 650°C under fuel gas atmosphere. The obtained results are as follows; 1) The corrosion rate of 18Cr12Ni2Mo steel in salt is affected by the applied potential. But the corrosion rates of 18Cr12Ni2Mo steel maintained at various potentials are nearly proportional to the one-half power of time. 2) The increase of K2CO3 in binary salt (Li2CO3/K2CO3) accelerates the corrosion rate. 3) The results obtained from electrochemical measurements are consistent with the tendency of the penetration depth obtained by corrosion test maintained at constant potential. Therefore, electrochemical measurement is effective to evaluate the corrosion rate of 18Cr12Ni2Mo steel in molten carbonate.