journal article·2020-10Open access

Carburization of metals by a chemical mechanism of carbon transport through molten fluoride salts

Kevin J. Chan, Preet M. Singh

Abstract

Abstract Carburization of structural alloys used in Fluoride Cooled High Temperature Reactors (FHR) can result from the interaction between the metal and graphite components and cause changes in alloy properties. However, carburization requires transport of carbon from graphite to alloy surfaces through the molten fluoride coolant. This work introduces an alternative to previously proposed carbon transport mechanisms. The new mechanism is based on the generation of carbonate ions (CO32−) by oxide impurities in the salt reacting with graphite. CO32− is then reduced on metal surfaces to deposit carbon. This work demonstrates the reduction of dissolved CO32− on pure Fe, Ni, Cr, Mo, and W surfaces without an applied potential in molten FLiNaK at 700 °C. We also demonstrate that the interaction between oxide and graphite in molten FLiNaK media produces CO32−.
Source: openaire · Quality: candidate unverified · Source record ↗

Research context

OpenAlex topics: Graphite, nuclear technology, radiation studies · Advanced ceramic materials synthesis · Thermal properties of materials

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References (47)

Show source-provided references
1. The molten salt reactor (MSR) in generation IV: overview and perspectives10.1016/j.pnucene.2014.02.014 ↗
2. Wright · 2018 · 34
3. Varma · 2012
4. Andreades · 2014 · 1
5. Corrosion of 316L Stainless steel alloy and hastelloy-N superalloy in molten eutectic LiF-NaF-KF salt and interaction with graphite10.13182/NT13-95 ↗
6. Impact of corrosion test container material in molten fluorides
7. Influence of graphite-alloy interactions on corrosion of Ni-Mo-Cr alloy in molten fluorides10.1016/j.jnucmat.2018.03.001 ↗
8. Mechanical behaviour of pack carburized AISI 316L austenitic stainless steel10.17159/2411-9717/2015/v115n12a6 ↗
9. Enhanced fatigue resistance in 316L austenitic stainless steel due to low-temperature paraequilibrium carburization10.1016/j.actamat.2007.06.025 ↗
10. Davis · 2002
11. Lovering · 1983
12. Corrosion of 316 stainless steel in high temperature molten Li2BeF4 (FLiBe) salt10.1016/j.jnucmat.2015.03.004 ↗
13. Corrosion-induced microstructural developments in 316 stainless steel during exposure to molten Li2BeF4(FLiBe) salt10.1016/j.jnucmat.2016.10.023 ↗
14. High-temperature corrosion of UNS N10003 in molten Li2BeF4 (FLiBe) salt10.5006/1657 ↗
15. Schulze · 1961 · vol. 3124
16. McCoy · 1972 · vol. 4829
17. Carburization effects on the corrosion of Cr, Fe, Ni, W, and Mo in fluoride-salt cooled high temperature reactor (FHR) coolant10.1016/j.anucene.2018.05.013 ↗
18. Ozeryanaya · 1975 · vol. 11 · 62
19. Study on the mechanism of deoxidization and purification for Li2BeF4 molten salt via graphite nanoparticles10.1016/j.jnucmat.2017.01.055 ↗
20. Electrodeposition of refractory carbide coatings from fluoride melts10.1007/BF01027499 ↗
21. Electrodeposition of tantalum carbide coatings from molten-salts10.1149/1.2119699 ↗
22. Molten-salt electrodeposition of refractory-metal carbide .2. Mechanism and nucleation studies10.1149/1.2221050 ↗
23. Schaffer · 1971 · vol. 4616
24. Preparation of high-purity molten FLiNaK salt by the hydrofluorination process10.1016/j.jfluchem.2017.03.006 ↗
25. The synthesis of borides, carbides and silicides of refractory metals in ionic-electronic melts
26. Dense carbon film coated 316L via in-situ synthesized CaC2 in FLiNaK molten salts and its high performance of anti-corrosion property10.1016/j.electacta.2019.05.100 ↗
27. Corrosion of Si, C, and SiC in molten salt10.1016/j.corsci.2018.10.027 ↗
28. Thermal-decomposition and reduction of carbonate ion in fluoride melts10.1149/1.2108802 ↗
29. Electrodeposition of carbon films from molten alkaline fluoride media10.1016/S0013-4686(02)00047-6 ↗
30. Theme and variations on tantalum-carbonate reactions in molten fluorides10.1149/1.2096543 ↗
31. Structural properties and electrochemistry of alpha-LiFeO210.1016/j.jpowsour.2011.09.054 ↗
32. Raman study of magnetite (Fe3O4): laser-induced thermal effects and oxidation10.1002/jrs.1056 ↗
33. Raman spectroscopy of Fe2O3 to 62 GPa10.2138/am-2002-2-314 ↗
34. Corrosion behavior of nickel-iron alloys in molten carbonate10.1149/1.1836387 ↗
35. Hot corrosion study of coated separator plates of molten carbonate fuel cells by slurry aluminides10.1016/S0257-8972(02)00417-6 ↗
36. Effects of temperature and partial pressure of CO2/O-2 on corrosion behaviour of stainless-steel in molten Li/Na carbonate salt10.1016/S0378-7753(00)00376-1 ↗
37. Raman spectroscopy of graphene and graphite: disorder, electron-phonon coupling, doping and nonadiabatic effects10.1016/j.ssc.2007.03.052 ↗
38. Application of a chronoamperometric measurement to the on-line monitoring of a lithium metal reduction for uranium oxide10.1016/j.jnucmat.2007.12.002 ↗
39. Corrosion of INCONEL alloy 625 in molten LiCl-Li2O-Li10.13182/NT15-126 ↗
40. Effects of O2- additive on corrosion behavior of Fe-Cr-Ni alloy in molten fluoride salts10.1016/j.corsci.2019.01.040 ↗
41. Corrosion behavior of chromium in molten carbonate10.1149/1.1836388 ↗
42. General equation for the determination of the crystallite size L-a of nanographite by Raman spectroscopy10.1063/1.2196057 ↗
43. Matrix-isolated Al2OF6 2- ion in molten and solid LiF/NaF/KF10.1021/ic000489x ↗
44. Infrared reflectivity and Raman-scattering of lithium-oxide single-crystals10.1016/0038-1098(84)90126-1 ↗
45. Measurement of the Raman spectrum of liquid water10.1063/1.475659 ↗
46. Raman-spectra of lithium hydroxide single-crystals10.1016/0022-3697(75)90149-3 ↗
47. Vibrational spectroscopic studies of aqueous alkali-metal bicarbonate and carbonate solutions10.1139/v73-106 ↗