Corrosion of nickel-based structural materials for nuclear reactors by molten fluoride salt: From bulk content of corrosion products to elemental imaging of corrosion changes

• Published in: Spectrochimica acta. Part B: Atomic spectroscopy Vol. 148; pp. 113 - 117
• Main Authors: Warchilová, T., Dillingerová, V., Škoda, R., Šimo, T., Matal, O., Vaculovič, T., Kanický, V.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 01-10-2018; Elsevier BV
• Subjects: Ablation; Corrosion; Corrosion products; Corrosion resistance; Corrosion tests; Electron probe; Electron probes; Elemental imaging; Emission analysis; EPMA; Ferritic stainless steels; Fluorides; Imaging techniques; Inductively coupled plasma mass spectrometry; LA-ICP-MS; Laser ablation; Lasers; Lithium fluoride; Mass spectrometry; Mass spectroscopy; Materials selection; Molten fluoride salt; Ni-based structural material; Nickel; Nickel base alloys; Nickel coatings; Nuclear reactors; Optical emission spectroscopy; Products; Protective coatings; Ratios; Salt; Steel; Molten fluoride salt; Elemental imaging; LA-ICP-MS; Corrosion; Ni-based structural material; EPMA
• ISSN: 0584-8547; 1873-3565
• DOI: 10.1016/j.sab.2018.06.010

This work is focused on the study of corrosion treatment of molten fluoride salt (MFS) on three candidate structural materials (Ni, ferritic steel with protective Ni coating, and Ni-based alloy). The samples were exposed to an MFS mixture (60 mol% LiF + 40 mol% NaF) at a temperature of 680 °C for 112, 350 and 1000 h. Their corrosion resistance was tested by the determination of the content of corrosion products in MFS by ICP-OES (Inductively Coupled Plasma with Optical Emission Spectrometry) analysis and comparison of elemental ratios. Distinctive differences in the ratios were found for ferritic steel with protective Ni coating. Morphological changes induced by MFS treatment were revealed and studied by EPMA (Electron Probe Micro Analysis) and LA-ICP-MS (Laser Ablation Inductively Coupled Plasma of Mass Spectrometry). Elemental maps of the corroded area were acquired by both methods. The analyses of corrosion products show that the best candidate material is nickel.
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•Corrosion of Ni-based materials induced by molten fluoride salt treatment.•Analysis of corrosion products•Imaging of corrosion changes by LA-ICP-MS and EPMA.