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About a critical thickness of the passive layer on iron at the flade potential
Author(s) -
Pinkowski A.
Publication year - 1986
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.19860371003
Subject(s) - critical point (mathematics) , capacitance , stoichiometry , layer (electronics) , materials science , lattice (music) , condensed matter physics , mechanics , physics , chemistry , nanotechnology , mathematics , mathematical analysis , electrode , quantum mechanics , acoustics
An analysis of capacitance potential data of passive iron on the basis of the theory of critical states yields a critical point near the Flade potential E F . The critical point is characterized by a minimal critical thickness of the passive layer of about 1.3 nm at E F , yielding a field strength within the passive film of 4.6 · 10 6 Vcm −1 . The Flade potential can be interpreted within the framework of the PIN model of the iron passive layer [9] as the minimal external “force”, necessary for the formation of stoichiometric γ‐Fe 2 O 3 . The system behavior near the critical point can be appropriate described by the short range order or lattice gas model.