Corrosion resistance of tungsten and tungsten alloys for spallation target in stagnant and flowing water

Noriaki Noji, Keisuke Kashiwagura, Noboru Akao, Saiko Soma, Nobuyoshi Hara, Katsuhisa Sugimoto

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

The corrosion resistance of W and its alloys for spallation targets was examined in stagnant and flowing water without irradiation. Commercial grade pure W (99.99%), high-purity W (99.999%), super high-purity CVD W (99.9999%), W-2%Ta alloy, W-5%Re alloy, and 93%W-7% Type 304 sintered alloy were used as specimens. Corrosion tests were carried out in boiling water at 373 K under atmosphere, in pressurized water under 1.013 MPa H2 at 373 and 453 K, and in H2-saturated flowing water at 373 K at flow-rates of 5 and 7 m·s-1. After the tests, specimen surfaces were analyzed by Auger electron spectroscopy and X-ray photoelectron spectroscopy. Electrochemical polarization curves of the specimens were measured in 1.0 kmol·m-3 Na2SO4 of pH 6.75 at 298 K. The corrosion mass loss in boiling water decreased in the order of W-Type 304 > W-5%Re > 99.99%W > 99.999%W > W-2%Ta > 99.9999%W. The corrosion mass loss in pressurized water was smaller than that in boiling water and decreased with increasing purity. In flowing water, the corrosion mass loss sharply increased with increasing flow-rate and increased with increasing purity of specimen. Surface films after the corrosion tests were composed of WO2, WOY (2 < Y < 3), WO3, and H2WO4. The anodic and cathodic polarization curves suggested that corrosion in neutral solution proceeds by an active dissolution-precipitation mechanism.

Original languageEnglish
Pages (from-to)1107-1115
Number of pages9
JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
Volume66
Issue number11
DOIs
Publication statusPublished - 2002 Nov

Keywords

  • Cooling water
  • Corrosion rate
  • Flow rate
  • Polarization curve
  • Spallation target
  • Surface film
  • Tungsten
  • Tungsten alloys

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

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