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Single-source-precursor synthesis of high temperature stable SiC/C/Fe nanocomposites from a processable hyperbranched polyferrocenylcarbosilane with high ceramic yield

Yu, Zhaoju and Yang, Le and Min, Hao and Zhang, Pei and Zhou, Cong and Riedel, Ralf (2014):
Single-source-precursor synthesis of high temperature stable SiC/C/Fe nanocomposites from a processable hyperbranched polyferrocenylcarbosilane with high ceramic yield.
In: Journal of Materials Chemistry C, 2 (6), Royal Society of Chemistry Publishing, p. 1057, ISSN 2050-7526,
[Online-Edition: http://dx.doi.org/10.1039/c3tc32088j],
[Article]

Abstract

Hydrosilylation of vinyl ferrocene with allylhydridopolycarbosilane was used to synthesize a processable hyperbranched polyferrocenylcarbosilane (HBPFCS), which was characterized by combination of gel permeation chromatography, Fourier transform infrared (FT-IR) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. The polymer-to-ceramic transformation of the HBPFCSs was then investigated by FT-IR and 13C MAS NMR spectroscopy as well as by thermal gravimetric analysis (TGA). A self-catalytic effect of ferrocenyl units in the HBPFCS skeleton on dehydrocoupling was found during a curing process at 170 °C resulting in a high ceramic yield of ca. 80% at 1200 °C in Ar. Finally, microstructures and magnetic properties of the final ceramics were studied by techniques such as X-ray diffraction, energy dispersive spectroscopy, Raman spectroscopy, transmission electron microscopy and vibrating sample magnetometry. The final ceramic (pyrolysis temperature ≥900 °C) is characterized by a microstructure comprised of a SiC/C/Fe nanocomposite. Turbostratic carbon layers located at the segregated α-Fe crystal boundary avoid interdiffusion and explain the exclusive existence of α-Fe in a SiC/C matrix even at 1300 °C. Variations of the iron content in the HBPFCSs and of the pyrolysis conditions facilitate the control of the composition and ceramic micro/nanostructure, influencing in particular magnetic properties of the final SiC/C/Fe nanocomposite ceramic.

Item Type: Article
Erschienen: 2014
Creators: Yu, Zhaoju and Yang, Le and Min, Hao and Zhang, Pei and Zhou, Cong and Riedel, Ralf
Title: Single-source-precursor synthesis of high temperature stable SiC/C/Fe nanocomposites from a processable hyperbranched polyferrocenylcarbosilane with high ceramic yield
Language: English
Abstract:

Hydrosilylation of vinyl ferrocene with allylhydridopolycarbosilane was used to synthesize a processable hyperbranched polyferrocenylcarbosilane (HBPFCS), which was characterized by combination of gel permeation chromatography, Fourier transform infrared (FT-IR) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. The polymer-to-ceramic transformation of the HBPFCSs was then investigated by FT-IR and 13C MAS NMR spectroscopy as well as by thermal gravimetric analysis (TGA). A self-catalytic effect of ferrocenyl units in the HBPFCS skeleton on dehydrocoupling was found during a curing process at 170 °C resulting in a high ceramic yield of ca. 80% at 1200 °C in Ar. Finally, microstructures and magnetic properties of the final ceramics were studied by techniques such as X-ray diffraction, energy dispersive spectroscopy, Raman spectroscopy, transmission electron microscopy and vibrating sample magnetometry. The final ceramic (pyrolysis temperature ≥900 °C) is characterized by a microstructure comprised of a SiC/C/Fe nanocomposite. Turbostratic carbon layers located at the segregated α-Fe crystal boundary avoid interdiffusion and explain the exclusive existence of α-Fe in a SiC/C matrix even at 1300 °C. Variations of the iron content in the HBPFCSs and of the pyrolysis conditions facilitate the control of the composition and ceramic micro/nanostructure, influencing in particular magnetic properties of the final SiC/C/Fe nanocomposite ceramic.

Journal or Publication Title: Journal of Materials Chemistry C
Volume: 2
Number: 6
Publisher: Royal Society of Chemistry Publishing
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: 07 Jul 2014 11:45
Official URL: http://dx.doi.org/10.1039/c3tc32088j
Identification Number: doi:10.1039/c3tc32088j
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