Corrosion resistance of Ni base alloys in supercritical water containing Sulfuric acid: Dependencies on alloying elements

Yuzo Daigo, Yutaka Watanabe, Katsuo Sugahara, Takeshi Isobe

Research output: Contribution to journalConference articlepeer-review

Abstract

Supercritical water is recognized as a promising medium for various chemical processes. However, one of the major problems to industrial application of the processes is thought to be corrosion of structural materials. In this paper, dependencies of corrosion resistance on alloying elements were investigated on twelve kinds of nickel base alloys in 400°C30MPa and 400°C60MPa supercritical water containing O.Olmol/kg sulfuric acid. The investigations reveals that Cr controls the corrosion resistance of the alloys in the test conditions and thresholds of changes in improvement rate in corrosion resistance with increasing Cr content are observed for the testing pressures. Properties of oxide on the specimens are examined by X-ray diffraction technique (XRD) to investigate correlation between the corrosion resistance of the Ni base alloys and crystallinity of the oxides on the Ni base alloys. The investigation suggests that corrosion resistance of the alloys improve with higher oxide crystallinity. The reasons for the effect of crystallinity on corrosion resistance are discussed.

Original languageEnglish
Pages (from-to)74131-741313
Number of pages667183
JournalNACE - International Corrosion Conference Series
Publication statusPublished - 2007 Dec 1
EventCorrosion 2007 - Nashville, TN, United States
Duration: 2007 Mar 112007 Mar 15

Keywords

  • Chromium
  • Corrosion
  • Crystallinity of oxide
  • Ni base alloy
  • Sulfuric acid
  • Supercritical water
  • X-ray diffraction

ASJC Scopus subject areas

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

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