Compatibility of nickel-based alloys with supercritical water applications: Aging effects on corrosion resistance and mechanical properties

Y. Daigo, Y. Watanabe, K. Sugahara, T. Isobe

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

Corrosion-resistant Ni-based alloys are thought to be strong candidates as a structural material for chemical processes using supercritical water (SCW). In recent years, Cr was considered as the most important alloying element to improve corrosion resistance in SCW. However, high Cr content can cause a phase transformation in Ni-based alloys because of poor phase stability at elevated temperatures for SCW processes from 400°C up to 650°C. The change in the microstructure of the alloy can lead to degradation in corrosion resistance and mechanical properties. In this study, thermal aging effects on corrosion resistance and mechanical properties of various Ni-based alloys were investigated through a corrosion test in SCW containing 0.01 mol/kg sulfuric acid (H2SO4) at 400°C/30 MPa and using Charpy impact tests. A reduction in impact toughness was observed for all the alloys tested, and the reduction in corrosion resistance was more significant for alloys with higher Cr content. The importance of susceptibility to thermal aging in materials selection for supercritical applications was discussed.

Original languageEnglish
Pages (from-to)174-181
Number of pages8
JournalCorrosion
Volume62
Issue number2
DOIs
Publication statusPublished - 2006 Feb

Keywords

  • Aging effect
  • Charpy impact value
  • Degradation
  • Fracture toughness
  • Mechanical property
  • Nickel-based alloy
  • Supercritical water

ASJC Scopus subject areas

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

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