Acta Metallurgica Sinica (English Letters) ›› 2023, Vol. 36 ›› Issue (5): 745-757.DOI: 10.1007/s40195-022-01490-8

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Effects of Aerobic and Anoxic Conditions on the Corrosion Behavior of NiCu Low Alloy Steel in the Simulated Groundwater Solutions

Xin Wei1, Yupeng Sun1,2, Junhua Dong1(), Nan Chen1, Qiying Ren1, Wei Ke3   

  1. 1Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China
    2School of Materials Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
    3Environmental Corrosion Centre of Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China
  • Received:2022-06-09 Revised:2022-08-07 Accepted:2022-08-24 Online:2022-12-04 Published:2022-12-04
  • Contact: Junhua Dong

Abstract:

The present work focused on investigating the corrosion behavior of NiCu low alloy steel in 0.05 M NaHCO3 solutions with different Cl concentrations under the aerobic-anoxic condition. The results showed that NiCu steel tended to be pseudo-passivated in the solutions of 0.05 M NaHCO3 and 0.05 M NaHCO3 + 0.01 M NaCl exposed to air. The cathodic process transformed from oxygen reduction to the common reduction of oxygen and α-FeOOH, while the anodic process was the iron dissolution. As Cl increased to 0.1 M, the steel tended to be activity dissolution. Due to the blocking effect of rust layer on the oxygen, the cathodic process transformed to the reduction of α-FeOOH. After the solutions were deoxidized, the cathodic process was controlled by only rust reduction. Meanwhile, both the cathodic process and anodic process of NiCu steel corrosion were significantly inhibited. During the whole aerobic-anoxic immersion, the corrosion rate of NiCu steel increased with Cl concentration. It was not only related to the promotion of Cl on the anodic dissolution of steel, but also related to the cathodic reduction of more α-FeOOH generated, which could accelerate the cathodic process.

Key words: Low alloy steel, Aerobic-anoxic condition, Corrosion behavior, Corrosion products, Electrochemical measurements