The Impact of Impurities on Alloy Behavior in Supercritical CO2 at 700 °C

Juho Lehmusto, James M. Kurley, Michael J. Lance, James R. Keiser, Bruce A. Pint

Research output: Contribution to journalArticleScientificpeer-review

15 Citations (Scopus)
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As part of round robin testing, specimens of commercial alloys 316, 120, 625, and 740 were exposed to 20 MPa research grade CO2 at 700 °C for up to 1500 h. The first set of specimens had higher mass gain likely due to impurities not flushed from the autoclave at startup. After this issue was corrected, an identical set of specimens exhibited lower mass gains for both the Fe- and Ni-based alloys. The differences in reaction products were characterized to understand the effect of impurities under these conditions. As suggested by the mass change, thicker oxides were formed in each case, primarily for the Fe-based alloys. For the Ni-based alloys, the difference was primarily in the transient stage of oxidation with no change in rate constant. Alloy 120 exhibited increased internal attack, and differences in the scale phases formed were characterized to better understand the effect of impurities. Alloy 740 primarily exhibited a greater depth of internal attack in the first run.

Original languageEnglish
Pages (from-to)95–111
JournalOxidation of Metals
Issue number1-2
Publication statusPublished - 2020
MoE publication typeA1 Journal article-refereed


  • Supercritical CO2
  • Impurities
  • Internal oxidation
  • Cr-rich oxide scale


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