Bright O. Okonkwo , Chaewon Kim , Taejeong An , Changheui Jang , Dokyu Kang , Wonseok Yang , Sungyeol Choi
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引用次数: 0
Abstract
The corrosion behaviour of Al-containing alloys in KCl-MgCl2 at 700 °C was investigated and compared with that of commercial alloys. The developed Al-containing alloys showed less or similar weight loss compared to Hastelloy N owing to Al-rich oxide formation. While 316 SS showed both uniform and localised corrosion, a high Al-containing alloy was almost unattacked by any form of corrosion. The SEM map in this study innovatively showed and confirmed the high Cr depletion at the top matrix layer of the exposed 316 SS alloy. It was found that the primary controlling mechanism of corrosion is the outward diffusion of metal ions promoted by the volatile metal chlorides, while Cr diffusion was detrimental, Al diffusion was beneficial in mitigating corrosion via the formation of Al oxides. Noteworthily, this study revealed that the KCl-MgCl2 salt was very corrosive to the 316 SS, and its interaction led to an obvious intergranular corrosion arising from Cr-depletion of the grain boundaries due to the high Cr content of the 316 SS. While for the high Al-containing alloys, the ACES with lower Al content and higher Ni content exhibited a higher corrosion rate when in contact with KCl-MgCl2salt than the ADSS with higher Al content and lower Ni content. The mechanism of electrochemical interaction between the KCl-MgCl2 salt and the high Al-containing alloys was that, the increased Al content and decreased Ni content enabled the formation of α – Al2O3, which provided excellent protective barrier against corrosion attack, while, the lower Al and higher Ni contents lead to the formation of Mg and Ni aluminate oxides. These oxides were less protective against corrosion attack in the molten salt environment.
期刊介绍:
The Journal of Nuclear Materials publishes high quality papers in materials research for nuclear applications, primarily fission reactors, fusion reactors, and similar environments including radiation areas of charged particle accelerators. Both original research and critical review papers covering experimental, theoretical, and computational aspects of either fundamental or applied nature are welcome.
The breadth of the field is such that a wide range of processes and properties in the field of materials science and engineering is of interest to the readership, spanning atom-scale processes, microstructures, thermodynamics, mechanical properties, physical properties, and corrosion, for example.
Topics covered by JNM
Fission reactor materials, including fuels, cladding, core structures, pressure vessels, coolant interactions with materials, moderator and control components, fission product behavior.
Materials aspects of the entire fuel cycle.
Materials aspects of the actinides and their compounds.
Performance of nuclear waste materials; materials aspects of the immobilization of wastes.
Fusion reactor materials, including first walls, blankets, insulators and magnets.
Neutron and charged particle radiation effects in materials, including defects, transmutations, microstructures, phase changes and macroscopic properties.
Interaction of plasmas, ion beams, electron beams and electromagnetic radiation with materials relevant to nuclear systems.