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Single-source-precursor synthesis of soft magnetic Fe3Si- and Fe5Si3-containing SiOC ceramic nanocomposites

Hojamberdiev, Mirabbos and Prasad, Ravi Mohan and Fasel, Claudia and Riedel, Ralf and Ionescu, Emanuel (2013):
Single-source-precursor synthesis of soft magnetic Fe3Si- and Fe5Si3-containing SiOC ceramic nanocomposites.
33, In: Journal of the European Ceramic Society, (13-14), E, pp. 2465-2472, ISSN 09552219, [Online-Edition: http://dx.doi.org/10.1016/j.jeurceramsoc.2013.04.005],
[Article]

Abstract

We present here the single-source-precursor synthesis of Fe3Si and Fe5Si3-containing SiOC ceramic nanocomposites and investigation of their magnetic properties. The materials were prepared upon chemical modification of a hydroxy- and ethoxy-substituted polymethylsilsesquioxane with iron (III) acetylacetonate (Fe(acac)3) in different amounts (5, 15, 30 and 50 wt%), followed by cross-linking at 180 °C and pyrolysis in argon at temperatures ranging from 1000 °C to 1500 °C. The polymer-to-ceramic transformation of the iron-modified polysilsesquioxane and the evolution at high temperatures of the synthesized SiFeOC-based nanocomposite were studied by means of thermogravimetric analysis (TGA) coupled with evolved gas analysis (EGA) as well as X-ray diffraction (XRD). Upon pyrolysis at 1100 °C, the non-modified polysilsesquioxane converts into an amorphous SiOC ceramic; whereas the iron-modified precursors lead to Fe3Si/SiOC nanocomposites. Annealing of Fe3Si/SiOC at temperatures exceeding 1300 °C induced the crystallization of Fe5Si3 and β-SiC. The crystallization of the different iron-containing phases at different temperatures is considered to be a consequence of the in situ generation of a Fe–C–Si alloy within the materials during pyrolysis. Depending on the Fe and Si content in the alloy, either Fe3Si and graphitic carbon (at 1000–1200 °C) or Fe5Si3 and β-SiC (at T > 1300 °C) crystallize. All SiFeOC-based ceramic samples were found to exhibit soft magnetic properties. Magnetization versus applied field measurements of the samples show a saturation magnetization up to 26.0 emu/g, depending on the Fe content within the SiFeOC-based samples as well as on the crystalline iron silicide phases formed during pyrolysis.

Item Type: Article
Erschienen: 2013
Creators: Hojamberdiev, Mirabbos and Prasad, Ravi Mohan and Fasel, Claudia and Riedel, Ralf and Ionescu, Emanuel
Title: Single-source-precursor synthesis of soft magnetic Fe3Si- and Fe5Si3-containing SiOC ceramic nanocomposites
Language: English
Abstract:

We present here the single-source-precursor synthesis of Fe3Si and Fe5Si3-containing SiOC ceramic nanocomposites and investigation of their magnetic properties. The materials were prepared upon chemical modification of a hydroxy- and ethoxy-substituted polymethylsilsesquioxane with iron (III) acetylacetonate (Fe(acac)3) in different amounts (5, 15, 30 and 50 wt%), followed by cross-linking at 180 °C and pyrolysis in argon at temperatures ranging from 1000 °C to 1500 °C. The polymer-to-ceramic transformation of the iron-modified polysilsesquioxane and the evolution at high temperatures of the synthesized SiFeOC-based nanocomposite were studied by means of thermogravimetric analysis (TGA) coupled with evolved gas analysis (EGA) as well as X-ray diffraction (XRD). Upon pyrolysis at 1100 °C, the non-modified polysilsesquioxane converts into an amorphous SiOC ceramic; whereas the iron-modified precursors lead to Fe3Si/SiOC nanocomposites. Annealing of Fe3Si/SiOC at temperatures exceeding 1300 °C induced the crystallization of Fe5Si3 and β-SiC. The crystallization of the different iron-containing phases at different temperatures is considered to be a consequence of the in situ generation of a Fe–C–Si alloy within the materials during pyrolysis. Depending on the Fe and Si content in the alloy, either Fe3Si and graphitic carbon (at 1000–1200 °C) or Fe5Si3 and β-SiC (at T > 1300 °C) crystallize. All SiFeOC-based ceramic samples were found to exhibit soft magnetic properties. Magnetization versus applied field measurements of the samples show a saturation magnetization up to 26.0 emu/g, depending on the Fe content within the SiFeOC-based samples as well as on the crystalline iron silicide phases formed during pyrolysis.

Journal or Publication Title: Journal of the European Ceramic Society
Volume: 33
Number: 13-14
Publisher: E
Uncontrolled Keywords: Iron silicides, Silicon oxycarbide, Polymer-derived ceramics (PDCs), Iron (III) acetylacetonate, Soft magnetic properties
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Dispersive Solids
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 21 Feb 2014 08:27
Official URL: http://dx.doi.org/10.1016/j.jeurceramsoc.2013.04.005
Identification Number: doi:10.1016/j.jeurceramsoc.2013.04.005
Funders: MH would like to thank the Alexander von Humboldt (AvH) Stiftung for the award of a postdoctoral research fellowship under which the present study was carried out., EI acknowledges financial support from the German Science Foundation DFG (IO/64-1, SPP 1181 NANOMAT).
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