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Title: Initial assessment of Ni-base alloy performance in 0.1 MPa and supercritical CO 2

There is considerable interest in increasing the working temperature of both open and closed supercritical CO 2 (sCO 2) cycles to ≥700 °C. At these temperatures, it is unlikely that any Fe-base alloys have suitable strength and therefore the focus is on Ni-base alloys for this application. To begin addressing the lack of compatibility data under these conditions, initial work exposed a wide range of candidate alloys in 500-h exposures at 20 MPa (200 bar) CO 2 at 650 -750 °C in high purity CO 2. In general, the reaction products were thin and protective in these exposures. A smaller group of alloy coupons focusing on chromia- and alumina-forming alloys was exposed for 500h in 0.1 MPa (1bar) air, CO 2, CO 2+O 2 and CO 2+H 2O for comparison. Thus, the thin surface oxides formed were very similar to those formed at high pressure and no clear detrimental effect of CO 2 oxidation or O 2 or H 2O impurities could be observed in these exposures.
Authors:
 [1] ;  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Journal of The Minerals, Metals & Materials Society
Additional Journal Information:
Journal Volume: 67; Journal Issue: 11; Journal ID: ISSN 1047-4838
Publisher:
Springer
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Fossil Energy (FE)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; supercritical CO2; Ni-base alloys; corrosion
OSTI Identifier:
1225426