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Title: Technical Note: Characterization of Corrosion Films Formed on Austenitic Stainless Steel in Supercritical CO2 Containing H2O and O2

Journal Article · · Corrosion
DOI: https://doi.org/10.5006/2726 · OSTI ID:1509737
 [1];  [2];  [3];  [3];  [3]
  1. National Energy Technology Lab. (NETL), Albany, OR (United States); AECOM, South Park, PA (United States)
  2. National Energy Technology Laboratory, Pittsburgh, PA (United States)
  3. National Energy Technology Lab. (NETL), Albany, OR (United States)

Future technologies require structural alloys resistant to corrosion in supercritical CO2 (sCO2) fluids containing impurities such as H2O and O2. Traditional pipeline steels are potentially unsuitable for these environments and more corrosion resistant alloys such as stainless steels might be required. Little is known about the corrosion products formed on, and hence the processes which control corrosion of, stainless steels in impure sCO2 environments. In this study, austenitic stainless steel 347H (UNS S34709) was exposed to sCO2 containing H2O and O2 at 8 MPa and 50°C or 250°C, and separately to the aqueous phase in equilibrium with the sCO2 at 50°C, to simulate conditions expected in sCO2-based power cycles and carbon capture and storage pipelines. Only thin (< 20 nm) surface films formed after 500 h resulting in small mass changes and corrosion rates < 10–4 mm/y, suggesting the material resists significant degradation in these environments. X-ray photoelectron spectroscopy and transmission electron microscopy were used to characterize the corrosion films in detail. Here, the exposure to the aqueous phase resulted in a thin (< 5 nm) Cr-oxide and/or -hydroxide passive film, while exposure to sCO2 phases resulted in a multilayer Fe-rich oxide structure characteristic of a gas-phase oxidation process.

Research Organization:
National Energy Technology Laboratory (NETL), Pittsburgh, PA, Morgantown, WV, and Albany, OR (United States)
Sponsoring Organization:
FE; USDOE
Grant/Contract Number:
FE0004000
OSTI ID:
1509737
Alternate ID(s):
OSTI ID: 1467019
Report Number(s):
CONTR-PUB-579
Journal Information:
Corrosion, Journal Name: Corrosion Journal Issue: 10 Vol. 74; ISSN 0010-9312
Publisher:
NACE InternationalCopyright Statement
Country of Publication:
United States
Language:
English