Mechanisms for oxidation and passive behavior of nickel in molten carbonate

Journal Article · Mon Jul 01 04:00:00 EDT 1996 · Journal of the Electrochemical Society

DOI:https://doi.org/10.1149/1.1836993· OSTI ID:367777

Vossen, J P.T. ^[1]; Ament, P C.H.; Wit, J H.W. de ^[2]

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1. Netherlands Energy Research Foundation ECN, Petten (Netherlands)
2. Delft Univ. of Technology (Netherlands)

The oxidation and passivation mechanism and the passive behavior of nickel in molten carbonate have been investigated with impedance measurements, quasi-stationary polarization curve measurements, and scanning electron microscopy. The oxidation of nickel probably proceeds according to a dissolution and reprecipitation process. The slowest steps in the reaction sequence are probably dissociation of carbonate and diffusion of the formed NiO to the surface. In the passive range, it is most likely that dissolution of Ni{sup 2+} proceeds after diffusion of Ni{sup 2+} through the oxide layer. The Ni{sup 2+} is formed at the metal/oxide interface. This reaction is accompanied by the incorporation of an oxygen ion and nickel vacancy in the NiO lattice. The trivalent nickel ions and the nickel vacancy diffuse to the bulk of the oxide scale. The slowest step in this sequence is likely the dissociation of the carbonate ions and the subsequent incorporation of the oxygen ion in the NiO lattice.

• Sponsoring Organization: USDOE
• OSTI ID: 367777
• Journal Information: Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 7 Vol. 143; ISSN 0013-4651; ISSN JESOAN
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
36 MATERIALS SCIENCE
BATTERY SEPARATORS
CARBONATES
CHEMICAL REACTION KINETICS
COATINGS
DISSOCIATION
MOLTEN CARBONATE FUEL CELLS
NICKEL
NICKEL OXIDES
OXIDATION
PASSIVATION