Corrosion behavior of pre-oxidized HR-224 superalloy in supercritical water environment at 700 °C

Corrosion of cladding materials in supercritical water (SCW) environment is a key reliability issue for the safety of nuclear power plant. In this study, we propose to use the pre-oxidized treatment to provide better corrosion resistance of cladding materials in the SCW environment. The nickel-based...

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Bibliographic Details
Published in:Journal of nuclear materials 2018-07, Vol.505, p.7-14
Main Authors: Liu, Yu-Chen, Chen, Shih-Ming, Ouyang, Fan-Yi, Kai, Ji-Jung
Format: Article
Language:English
Subjects:
Alumina-forming alloys
Aluminum alloys
Aluminum oxide
Chromium
Cladding
Corrosion
Corrosion resistance
Corrosion resistant alloys
Electron microscopes
Electron microscopy
Environment
High temperature corrosion
High temperature physics
Marine environment
Metal ions
Migration
Nickel
Nickel base alloys
Nuclear accidents & safety
Nuclear energy
Nuclear engineering
Nuclear power plants
Nuclear safety
Oxidation
Oxygen content
Plant reliability
Superalloys
Supercritical water
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Summary:Corrosion of cladding materials in supercritical water (SCW) environment is a key reliability issue for the safety of nuclear power plant. In this study, we propose to use the pre-oxidized treatment to provide better corrosion resistance of cladding materials in the SCW environment. The nickel-based superalloy HR-224 was first pre-oxidized in flowing air at 982 °C for 100 h to establish a continuous and dense scales and then exposed in the SCW environment with high oxygen content (8.3 ppm) at 700 °C and 24.8 MPa for cyclic oxidation testing up to 1300 h. The pre-oxidized samples exhibit better corrosion resistance than as-received samples in the SCW environment. After pre-oxidizing process, triple scales, Ni(Cr, Fe)2O4 spinel/Cr2O3/α-Al2O3 were observed, and the growth of inner α-Al2O3 layer is predominant in the SCW environment. The α-Al2O3 layer in pre-oxidized samples was found to effectively decrease outward migration of metal ions in Alloy HR-224 and thus provides better corrosion resistance than as-received samples in SCW environment. •Pre-oxidized HR-224 provides better corrosion resistance than as-received one.•Ni(Cr, Fe)2O4 spinel/Cr2O3/α-Al2O3 were observed after pre-oxidized treatment.•Continuous Al2O3 layer can effectively decrease outward migration of metal ions.
ISSN:0022-3115
1873-4820
DOI:10.1016/j.jnucmat.2018.03.053