Corrosion resistance of FE-CR and NI-CR alloys in oxidizing supercritical HCL solution

Nobuyoshi Hara, Satoshi Tanaka, Saiko Soma, Katsuhisa Sugimoto

Research output: Contribution to journalConference articlepeer-review

6 Citations (Scopus)

Abstract

The corrosion behavior of binary Fe-Cr (10-40%Cr) and Ni-Cr alloys (10-30%Cr) has been examined in 1mM-HCl+0.6M-H2O2 at 500°C and 29.4MPa. By comparing the weight loss due to oxidation with that due to dissolution and examining the time dependence of the weight losses, it was found that oxidation was a dominant corrosion process of the alloys at 500°C. The corrosion rate decreased with increasing Cr content and reached a minimum at 30% and 20% Cr for Fe-Cr and Ni-Cr alloys, respectively. A further increase in the Cr content increased the corrosion rate. These results can be explained by taking account of both beneficial and detrimental effects of Cr: increasing the Cr content improves oxidation resistance but accelerates transpassive dissolution at 500°C. The addition of a small amount of Mo (1-2%) to Fe-Cr alloys (> 25%Cr) was found to be effective for further improvements of the corrosion resistance of the alloys. The corrosion tests of Fe-Cr alloys were performed at various temperatures between 300 and 500°C. The results of the tests suggested that the transpassive dissolution rate of Cr was high at temperatures around 350°C and above 500°C, but was low at temperatures of 400-450°C. At these temperatures, which is just above the critical point, the corrosion resistance of Fe-Cr alloys was improved significantly with increasing Cr content and no detrimental effect of Cr could be observed even at the Cr contents as high as 40%.

Original languageEnglish
JournalNACE - International Corrosion Conference Series
Volume2002-April
Publication statusPublished - 2002 Jan 1
EventCorrosion 2002 - Denver, United States
Duration: 2002 Apr 72002 Apr 11

Keywords

  • Dissolution
  • Fe-Cr alloy
  • Hydrochloric acid
  • Ni-Cr alloy
  • Oxidation
  • Pitting corrosion
  • Supercritical water oxidation
  • Transpassive dissolution

ASJC Scopus subject areas

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

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