Passivation of α-Fe nanoparticle by epitaxial γ-Fe2O3 shell

K. K. Fung; Boxiong Qin; X. X. Zhang

doi:10.1016/S0921-5093(00)00717-6

Passivation of α-Fe nanoparticle by epitaxial γ-Fe₂O₃ shell

K. K. Fung^*, Boxiong Qin, X. X. Zhang

^*Corresponding author for this work

Research output: Contribution to journal › Conference article › peer-review

77 Scopus citations

Abstract

Nanoparticles of iron prepared by inert gas condensation of plasma evaporated vapour exhibit remarkable resistance to oxidation. They remain rust free in air and in water for years. We have found by transmission electron microscopy and X-ray photoelectron spectroscopy, that all the passivated nanoparticles of iron are covered by an epitaxial shell of γ-Fe₂O₃ about 4 nm thick. The epitaxial relationship between the γ-Fe₂O₃ shell and the iron core is (001)_γ-Fe(2)O(3)∥(001)_α-Fe, and [110]_γ-Fe(2)O(3)∥[100]_α-Fe, [1̄10]_γ-Fe(2)O(3)∥[010]_α-Fe. The passivation of the nanoparticles of iron by an epitaxial oxide can be accounted for by the Caberra-Mott theory of oxidation of metal. The oxide layer grows rapidly at 420 K but slows down dramatically when the layer thickens. When the oxide layer thickens to 4 nm in a few hours, growth virtually stops. The 4-nm epitaxial oxide shell protects the iron core from further oxidation at room temperature.

Original language	English (US)
Pages (from-to)	135-138
Number of pages	4
Journal	Materials Science and Engineering A
Volume	286
Issue number	1
DOIs	https://doi.org/10.1016/S0921-5093(00)00717-6
State	Published - Jun 30 2000
Externally published	Yes
Event	IUMRS-ICAM'99: Symposium A - Nanostructured Materials, The 5th IUMRS International Conference on Advanced Materials - Beijing, China Duration: Jun 13 1999 → Jun 18 1999

Bibliographical note

Funding Information:
The authors would like to thank J. Zheng and Dr L. Weng of the Materials Characterization and Preparation Facility of the Hong Kong University of Science and Technology for their help in the X-ray diffraction and XPS. This work was supported in part by the Research Grants Council of Hong Kong, grant no. HKUST6111/98P.

Keywords

Epitaxy
Iron
Nanoparticle
Oxidation
TEM
γ-FeO

ASJC Scopus subject areas

General Materials Science
Condensed Matter Physics
Mechanics of Materials
Mechanical Engineering

Access to Document

10.1016/S0921-5093(00)00717-6

Cite this

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title = "Passivation of α-Fe nanoparticle by epitaxial γ-Fe2O3 shell",

abstract = "Nanoparticles of iron prepared by inert gas condensation of plasma evaporated vapour exhibit remarkable resistance to oxidation. They remain rust free in air and in water for years. We have found by transmission electron microscopy and X-ray photoelectron spectroscopy, that all the passivated nanoparticles of iron are covered by an epitaxial shell of γ-Fe2O3 about 4 nm thick. The epitaxial relationship between the γ-Fe2O3 shell and the iron core is (001)γ-Fe(2)O(3)∥(001)α-Fe, and [110]γ-Fe(2)O(3)∥[100]α-Fe, [{\=1}10]γ-Fe(2)O(3)∥[010]α-Fe. The passivation of the nanoparticles of iron by an epitaxial oxide can be accounted for by the Caberra-Mott theory of oxidation of metal. The oxide layer grows rapidly at 420 K but slows down dramatically when the layer thickens. When the oxide layer thickens to 4 nm in a few hours, growth virtually stops. The 4-nm epitaxial oxide shell protects the iron core from further oxidation at room temperature.",

keywords = "Epitaxy, Iron, Nanoparticle, Oxidation, TEM, γ-FeO",

author = "Fung, {K. K.} and Boxiong Qin and Zhang, {X. X.}",

note = "Funding Information: The authors would like to thank J. Zheng and Dr L. Weng of the Materials Characterization and Preparation Facility of the Hong Kong University of Science and Technology for their help in the X-ray diffraction and XPS. This work was supported in part by the Research Grants Council of Hong Kong, grant no. HKUST6111/98P. ; IUMRS-ICAM'99: Symposium A - Nanostructured Materials, The 5th IUMRS International Conference on Advanced Materials ; Conference date: 13-06-1999 Through 18-06-1999",

year = "2000",

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TY - JOUR

T1 - Passivation of α-Fe nanoparticle by epitaxial γ-Fe2O3 shell

AU - Fung, K. K.

AU - Qin, Boxiong

AU - Zhang, X. X.

N1 - Funding Information: The authors would like to thank J. Zheng and Dr L. Weng of the Materials Characterization and Preparation Facility of the Hong Kong University of Science and Technology for their help in the X-ray diffraction and XPS. This work was supported in part by the Research Grants Council of Hong Kong, grant no. HKUST6111/98P.

PY - 2000/6/30

Y1 - 2000/6/30

N2 - Nanoparticles of iron prepared by inert gas condensation of plasma evaporated vapour exhibit remarkable resistance to oxidation. They remain rust free in air and in water for years. We have found by transmission electron microscopy and X-ray photoelectron spectroscopy, that all the passivated nanoparticles of iron are covered by an epitaxial shell of γ-Fe2O3 about 4 nm thick. The epitaxial relationship between the γ-Fe2O3 shell and the iron core is (001)γ-Fe(2)O(3)∥(001)α-Fe, and [110]γ-Fe(2)O(3)∥[100]α-Fe, [1̄10]γ-Fe(2)O(3)∥[010]α-Fe. The passivation of the nanoparticles of iron by an epitaxial oxide can be accounted for by the Caberra-Mott theory of oxidation of metal. The oxide layer grows rapidly at 420 K but slows down dramatically when the layer thickens. When the oxide layer thickens to 4 nm in a few hours, growth virtually stops. The 4-nm epitaxial oxide shell protects the iron core from further oxidation at room temperature.

AB - Nanoparticles of iron prepared by inert gas condensation of plasma evaporated vapour exhibit remarkable resistance to oxidation. They remain rust free in air and in water for years. We have found by transmission electron microscopy and X-ray photoelectron spectroscopy, that all the passivated nanoparticles of iron are covered by an epitaxial shell of γ-Fe2O3 about 4 nm thick. The epitaxial relationship between the γ-Fe2O3 shell and the iron core is (001)γ-Fe(2)O(3)∥(001)α-Fe, and [110]γ-Fe(2)O(3)∥[100]α-Fe, [1̄10]γ-Fe(2)O(3)∥[010]α-Fe. The passivation of the nanoparticles of iron by an epitaxial oxide can be accounted for by the Caberra-Mott theory of oxidation of metal. The oxide layer grows rapidly at 420 K but slows down dramatically when the layer thickens. When the oxide layer thickens to 4 nm in a few hours, growth virtually stops. The 4-nm epitaxial oxide shell protects the iron core from further oxidation at room temperature.

KW - Epitaxy

KW - Iron

KW - Nanoparticle

KW - Oxidation

KW - TEM

KW - γ-FeO

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