Corrosion Resistance of Protective Coatings on 12Kh18N10T Steel in an FLiBe Melt

Molten FLiBe-based mixtures are promising technological media for molten-salt nuclear reactors (MSRs) due to their physicochemical properties. There is no structural material resistant to fluoride melts due to their high aggressiveness. It is purposeful to search for and develop new method of protecting structural materials, including the deposition of corrosion-resistant protective coatings. The corrosion behavior of laser-surfaced coatings made of STELLITE 6 alloy, WC–Ni/Cr composite material, metallic nickel, and NiCrSiBFe alloy on a 12Kh18N10T steel substrate is studied. Corrosion tests for 100 h have been carried out in the 73 LiF–27 BeF2 (mol %) salt melt at a temperature of 700°C. Quantitative and qualitative corrosion characteristics demonstrate that the coatings made of metallic nickel and STELLITE 6 alloy are most resistant. Samples with NiCrSiBFe and WC–Ni/Cr coatings have substantial defects (cracks) after deposition, and they are the main cause of their degradation during corrosion tests.