Hojamberdiev, Mirabbos ; Prasad, Ravi Mohan ; Fasel, Claudia ; Riedel, Ralf ; Ionescu, Emanuel (2013)
Single-source-precursor synthesis of soft magnetic Fe3Si- and Fe5Si3-containing SiOC ceramic nanocomposites.
In: Journal of the European Ceramic Society, 33 (13-14)
doi: 10.1016/j.jeurceramsoc.2013.04.005
Artikel, Bibliographie
Kurzbeschreibung (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.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2013 |
| Autor(en): | Hojamberdiev, Mirabbos ; Prasad, Ravi Mohan ; Fasel, Claudia ; Riedel, Ralf ; Ionescu, Emanuel |
| Art des Eintrags: | Bibliographie |
| Titel: | Single-source-precursor synthesis of soft magnetic Fe3Si- and Fe5Si3-containing SiOC ceramic nanocomposites |
| Sprache: | Englisch |
| Publikationsjahr: | November 2013 |
| Verlag: | E |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Journal of the European Ceramic Society |
| Jahrgang/Volume einer Zeitschrift: | 33 |
| (Heft-)Nummer: | 13-14 |
| DOI: | 10.1016/j.jeurceramsoc.2013.04.005 |
| Kurzbeschreibung (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. |
| Freie Schlagworte: | Iron silicides, Silicon oxycarbide, Polymer-derived ceramics (PDCs), Iron (III) acetylacetonate, Soft magnetic properties |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Disperse Feststoffe 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften |
| Hinterlegungsdatum: | 21 Feb 2014 08:27 |
| Letzte Änderung: | 21 Feb 2014 08:27 |
| PPN: | |
| Sponsoren: | 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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