Affiliation:
1. Institute of High-Temperature Electrochemistry, Ural Branch of the RAS
Abstract
The successful use of molten alkali metal fluorides as an electrolyte for high-temperature devices requires the development of such reactor materials that have high corrosion resistance in melts with compositions characteristic of liquid-salt mixing reactors. This is one of the most important unresolved problems. One of the effective ways to reduce corrosion losses is to create a layer on the surface of the material that protects the metal from the corrosive effects of the environment. In this paper, molybdenum insulating coatings on steel 12Kh18Ni10Ti obtained in molten salts of various compositions and by various methods are considered as protective layers. Experiments were carried out on the electrodeposition of molybdenum coatings on structural materials based on iron (steel 12Cr18Ni10Ti). The coatings obtained by the electrochemical method are inhomogeneous and easily exfoliating. The thickness of molybdenum coatings obtained from molten salts is 8.15 and 20.34 μm on steel in FLiNaK and LiCl–KCl melt, respectively. Corrosion tests have shown the inefficiency of the molybdenum coating obtained from both chloride and fluoride melts. The corrosion rate of 12Cr18Ni10Ti steel in FLiNaK/FLiNaK + 5% CeF3 melts at 650°C and a holding time of 100 hours decreases in the following row: 12Cr18Ni10Ti + Mo (0.75/0.77 mm/year) 12Cr18Ni10Ti (0.45/0.50 mm/year).
Publisher
The Russian Academy of Sciences
Reference35 articles.
1. Vas’ko A.T., Kovach S.K. Elektrokhimiya tugoplavkikh metallov [Electrochemistry of refractory metals]. Kiyev: Tekhnika, 1983. [In Russian].
2. Spitsyn V.I., Drobysheva T.I. Kozanskiy L.P. Khimicheskiye vzaimodeystviya v vol’framatnykh sistemakh. Khimiya soyedineniy Mo(VI) i W(VI) [Chemical interactions in tungstate systems. Chemistry of Mo(VI) and W(VI) compounds]. Novosibirsk: Nauka, 1989. P. 3. [In Russian].
3. Senderoff S., Mellors G.W. Electrodeposition of coherent deposits of refractory metals. V. Mechanism for the deposition of molybdenum from a chloride melt // J. Electrochem. Soc. 1967. 114. P. 556.
4. Brencic J.V., Cotton F.A. Mechanism for the deposition of molybdenum from a chloride melt // Inorg. Chem. 1970. 9. P. 351–358.
5. Inman D., Williams D.E. Electrochemistry – the past thirty years and the next thirty years. New York: Plenum Press, 1975.