Effects of hydrogen on the anodic behavior of Alloy 690 at 60 °C

Tichun Dan, Tetsuo Shoji, Zhanpeng Lu, Kazuhiko Sakaguchi, Jianqiu Wang, En Hou Han, Wei Ke

Research output: Contribution to journalArticlepeer-review

38 Citations (Scopus)

Abstract

Polarization and electrochemical impedance spectroscopy (EIS) measurements, Mott-Schottky (M-S) analysis and X-ray photoelectron spectroscopy (XPS) were used to investigate the effects of hydrogen on the anodic behavior of a one-dimensionally (1D) 25% cold worked (CW) Alloy 690 thermal treated (TT) in a boric acid and sodium sulphate solution at 60 °C. The pre-hydrogen-charged specimen exhibited a higher anodic current than that of the uncharged specimen below the transpassive potential. The charged hydrogen can be trapped in the metal. Electrochemical impedance spectroscopy (EIS) showed that the resistance capacitance loop of the hydrogen-charged specimen was significantly smaller than that of the uncharged specimen. Mott-Schottky analyses indicated that the passive film formed on Alloy 690 at -0.2 VSCE was an n-type semiconductor, with a p-n hetero-junction at 0.2 VSCE. Charged hydrogen increased the carrier density and the thickness of the passive film both at -0.2 VSCE and 0.2 VSCE. The Ni/Cr ratio in the surface film decreased after hydrogen charging, indicating that charged hydrogen could enhance the oxide film growth by increasing the OH- (O2-) concentrations through its reaction with vacancies. Crown

Original languageEnglish
Pages (from-to)1228-1236
Number of pages9
JournalCorrosion Science
Volume52
Issue number4
DOIs
Publication statusPublished - 2010 Apr 1

Keywords

  • A. Alloy 690
  • B. EIS
  • B. Mott-Schottky plot
  • B. XPS
  • C. Anodic behavior
  • C. Hydrogen charging

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Science(all)

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