High-temperature electrochemical corrosion behavior of SA106 Grade B carbon steel with corrosion inhibitors in HyBRID solution

The electrochemical corrosion behaviors of SA106 Grade B (SA106B) carbon steel in H2SO4-N2H4 and H2SO4-N2H4-CuSO4 solutions at 95 °C have been investigated with the addition of commercial corrosion inhibitors (CI#30 and No. 570S), to determine the stability of SA106B in the hydrazine-based reductive metal ion decontamination (HyBRID) process. The potentiodynamic polarization experiment revealed that the corrosion inhibitors were capable of lowering the corrosion rate of SA106B in H2SO4-N2H4 solution. It was found that the corrosion inhibitors induced formation of fixed surface layer on the carbon steel upon the corrosion. This corrosion inhibition performance was reduced in the presence of CuSO4 in the solution owing to the chemical reactions between organic compounds in the corrosion inhibitors and CuSO4. CI#30 showed a better corrosion inhibition effect in the H2SO4-N2H4-CuSO4 solution. Although the corrosion inhibitors can provide better stability to SA106B in the HyBRID solution, their application should be carefully considered because it may result in reduced decontamination performance and increased secondary waste generation.