Microstructure of iron particles reduced from silica-coated hematite in hydrogen

Yuichi Yonemochi, Motoyuki Iijima, Mayumi Tsukada, Hua Jiang, Esko I. Kauppinen, Mitsumasa Kimata, Masahiro Hasegawa, Hidehiro Kamiya (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

6 Citations (Scopus)

Abstract

Poly- and nearly monocrystalline hematite particles having diameters of around 2 and 0.1 μm, respectively, were prepared by the gel-sol method and coated with a uniform silica layer by the sol-gel method. The core in the silica shell was reduced to iron without agglomerate formation between the particles by using a hydrogen stream. The microstructure and morphology of these cores and the silica layers were examined by high-resolution transmission electron microscopy, and electron and X-ray diffraction analysis. In hematite particles, around 2 μm in diameter, the reduced products were mostly α-Fe, but partially magnetite. In hematite particles, around 0.1 μm in diameter, only α-Fe was observed. Most of the raw hematite and iron particles produced were monocrystalline, and part of core grew hexagonal prism-shaped monocrystalline particles. In the case of the growth of a crystal to a hexagonal prism, a nanometer-scaled space at the interface between the iron crystal core and the silica layer was discovered.
Original languageEnglish
Pages (from-to)621-637
JournalAdvanced Powder Technology
Volume16
Issue number6
DOIs
Publication statusPublished - 2005
MoE publication typeA1 Journal article-refereed

Fingerprint

Hematite
Silicon Dioxide
Hydrogen
Iron
Silica
Microstructure
Prisms
Sol-gel process
Ferrosoferric Oxide
Crystals
Magnetite
High resolution transmission electron microscopy
X ray diffraction analysis
ferric oxide
Electrons

Cite this

Yonemochi, Y., Iijima, M., Tsukada, M., Jiang, H., Kauppinen, E. I., Kimata, M., ... Kamiya, H. (2005). Microstructure of iron particles reduced from silica-coated hematite in hydrogen. Advanced Powder Technology, 16(6), 621-637. https://doi.org/10.1163/156855205774483325
Yonemochi, Yuichi ; Iijima, Motoyuki ; Tsukada, Mayumi ; Jiang, Hua ; Kauppinen, Esko I. ; Kimata, Mitsumasa ; Hasegawa, Masahiro ; Kamiya, Hidehiro. / Microstructure of iron particles reduced from silica-coated hematite in hydrogen. In: Advanced Powder Technology. 2005 ; Vol. 16, No. 6. pp. 621-637.
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abstract = "Poly- and nearly monocrystalline hematite particles having diameters of around 2 and 0.1 μm, respectively, were prepared by the gel-sol method and coated with a uniform silica layer by the sol-gel method. The core in the silica shell was reduced to iron without agglomerate formation between the particles by using a hydrogen stream. The microstructure and morphology of these cores and the silica layers were examined by high-resolution transmission electron microscopy, and electron and X-ray diffraction analysis. In hematite particles, around 2 μm in diameter, the reduced products were mostly α-Fe, but partially magnetite. In hematite particles, around 0.1 μm in diameter, only α-Fe was observed. Most of the raw hematite and iron particles produced were monocrystalline, and part of core grew hexagonal prism-shaped monocrystalline particles. In the case of the growth of a crystal to a hexagonal prism, a nanometer-scaled space at the interface between the iron crystal core and the silica layer was discovered.",
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Yonemochi, Y, Iijima, M, Tsukada, M, Jiang, H, Kauppinen, EI, Kimata, M, Hasegawa, M & Kamiya, H 2005, 'Microstructure of iron particles reduced from silica-coated hematite in hydrogen', Advanced Powder Technology, vol. 16, no. 6, pp. 621-637. https://doi.org/10.1163/156855205774483325

Microstructure of iron particles reduced from silica-coated hematite in hydrogen. / Yonemochi, Yuichi; Iijima, Motoyuki; Tsukada, Mayumi; Jiang, Hua; Kauppinen, Esko I.; Kimata, Mitsumasa; Hasegawa, Masahiro; Kamiya, Hidehiro (Corresponding Author).

In: Advanced Powder Technology, Vol. 16, No. 6, 2005, p. 621-637.

Research output: Contribution to journalArticleScientificpeer-review

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AU - Yonemochi, Yuichi

AU - Iijima, Motoyuki

AU - Tsukada, Mayumi

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AU - Kauppinen, Esko I.

AU - Kimata, Mitsumasa

AU - Hasegawa, Masahiro

AU - Kamiya, Hidehiro

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AB - Poly- and nearly monocrystalline hematite particles having diameters of around 2 and 0.1 μm, respectively, were prepared by the gel-sol method and coated with a uniform silica layer by the sol-gel method. The core in the silica shell was reduced to iron without agglomerate formation between the particles by using a hydrogen stream. The microstructure and morphology of these cores and the silica layers were examined by high-resolution transmission electron microscopy, and electron and X-ray diffraction analysis. In hematite particles, around 2 μm in diameter, the reduced products were mostly α-Fe, but partially magnetite. In hematite particles, around 0.1 μm in diameter, only α-Fe was observed. Most of the raw hematite and iron particles produced were monocrystalline, and part of core grew hexagonal prism-shaped monocrystalline particles. In the case of the growth of a crystal to a hexagonal prism, a nanometer-scaled space at the interface between the iron crystal core and the silica layer was discovered.

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