Acta Metallurgica Sinica (English Letters) ›› 2022, Vol. 35 ›› Issue (2): 326-340.DOI: 10.1007/s40195-021-01272-8

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Passivation Behavior of 2507 Super Duplex Stainless Steel in Hot Concentrated Seawater: Influence of Temperature and Seawater Concentration

Kang Zhao1,2, Xiao-Qi Li1, Li-Wei Wang1(), Qi-Rong Yang1, Lian-Jun Cheng1, Zhong-Yu Cui2()   

  1. 1College of Mechanical and Electrical Engineering, Qingdao University, Qingdao 266071, China
    2School of Materials Science and Engineering, Ocean University of China, Qingdao 266100, China
  • Received:2021-01-08 Revised:2021-04-25 Accepted:2021-05-05 Online:2022-02-10 Published:2021-10-28
  • Contact: Li-Wei Wang,Zhong-Yu Cui
  • About author:Zhong-Yu Cui, cuizhongyu@ouc.edu.cn
    Li-Wei Wang, ustbwangliwei@126.com;

Abstract:

The electrochemical behavior and passivation properties of 2507 super duplex stainless steel (SDSS) in the hot concentrated seawater with different concentrations at different temperatures are characterized by electrochemical methods and X-ray photoelectron spectroscopy. The passive film formed on 2507 SDSS belongs to n-type semiconductor and mainly composed of hydroxides and oxides of Fe and Cr under all circumstances. The protectiveness of the passive film decreases with the increase in temperature mainly because of the increase in defect density in the passive film. The corrosion resistance of 2507 decreases with the increase in seawater concentration, and the critical pitting temperature also decreases.

Key words: Stainless steel, Hot concentrated seawater, Passive film, Pitting