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SiC/HfyTa1−yCxN1−x/C ceramic nanocomposites with HfyTa1−yCxN1−x-carbon core–shell nanostructure and the influence of the carbon-shell thickness on electrical properties

Wen, Qingbo and Yu, Zhaoju and Xu, Yeping and Lu, Yan and Fasel, Claudia and Morita, Koji and Guillon, Olivier and Buntkowsky, Gerd and Ionescu, Emanuel and Riedel, Ralf (2018):
SiC/HfyTa1−yCxN1−x/C ceramic nanocomposites with HfyTa1−yCxN1−x-carbon core–shell nanostructure and the influence of the carbon-shell thickness on electrical properties.
In: Journal of Materials Chemistry C, Royal Society of Chemistry Publishing, pp. 855-864, 6, (4), ISSN 2050-7526, DOI: 10.1039/c7tc05023b, [Online-Edition: https://doi.org/10.1039/c7tc05023b],
[Article]

Abstract

Dense monolithic SiC/HfyTa1−yCxN1−x/C (y = 0, 0.2 and 0.7) ceramic nanocomposites were prepared upon spark plasma sintering of amorphous SiHfTaC(N) ceramic powders which were synthesized from single-source-precursors. The microstructural evolution of the ceramic powders was investigated using elemental analysis, X-ray diffraction, Raman spectroscopy and transmission electron microscopy (TEM). The results reveal that the powdered and dense monoliths of SiC/HfyTa1−yCxN1−x/C ceramic nanocomposites annealed at T ≥ 1700 °C and at 2200 °C, respectively, are characterized by the presence of a homogeneous dispersion of HfyTa1−yCxN1−x-carbon core–shell nanoparticles within a β-SiC matrix. Hf/Ta atomic ratios (or y values) of the in situ generated HfyTa1−yCxN1−x-carbon core–shell nanoparticles can be controlled precisely by molecular tailoring of the preceramic precursors, which further tunes the thickness of the in situ formed carbon shell. Interestingly, with increasing the value y the thickness of the carbon shell increases, while the electrical conductivity of the dense monolithic SiC/HfyTa1−yCxN1−x/C (y = 0, 0.2 and 0.7) nanocomposites significantly reduces. The unique HfyTa1−yCxN1−x-carbon core–shell nanostructure opens a new strategy towards tailoring the electrical conductivity of SiC/HfyTa1−yCxN1−x/C nanocomposites for potential electromagnetic applications in harsh environments.

Item Type: Article
Erschienen: 2018
Creators: Wen, Qingbo and Yu, Zhaoju and Xu, Yeping and Lu, Yan and Fasel, Claudia and Morita, Koji and Guillon, Olivier and Buntkowsky, Gerd and Ionescu, Emanuel and Riedel, Ralf
Title: SiC/HfyTa1−yCxN1−x/C ceramic nanocomposites with HfyTa1−yCxN1−x-carbon core–shell nanostructure and the influence of the carbon-shell thickness on electrical properties
Language: English
Abstract:

Dense monolithic SiC/HfyTa1−yCxN1−x/C (y = 0, 0.2 and 0.7) ceramic nanocomposites were prepared upon spark plasma sintering of amorphous SiHfTaC(N) ceramic powders which were synthesized from single-source-precursors. The microstructural evolution of the ceramic powders was investigated using elemental analysis, X-ray diffraction, Raman spectroscopy and transmission electron microscopy (TEM). The results reveal that the powdered and dense monoliths of SiC/HfyTa1−yCxN1−x/C ceramic nanocomposites annealed at T ≥ 1700 °C and at 2200 °C, respectively, are characterized by the presence of a homogeneous dispersion of HfyTa1−yCxN1−x-carbon core–shell nanoparticles within a β-SiC matrix. Hf/Ta atomic ratios (or y values) of the in situ generated HfyTa1−yCxN1−x-carbon core–shell nanoparticles can be controlled precisely by molecular tailoring of the preceramic precursors, which further tunes the thickness of the in situ formed carbon shell. Interestingly, with increasing the value y the thickness of the carbon shell increases, while the electrical conductivity of the dense monolithic SiC/HfyTa1−yCxN1−x/C (y = 0, 0.2 and 0.7) nanocomposites significantly reduces. The unique HfyTa1−yCxN1−x-carbon core–shell nanostructure opens a new strategy towards tailoring the electrical conductivity of SiC/HfyTa1−yCxN1−x/C nanocomposites for potential electromagnetic applications in harsh environments.

Journal or Publication Title: Journal of Materials Chemistry C
Volume: 6
Number: 4
Publisher: Royal Society of Chemistry Publishing
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Dispersive Solids
07 Department of Chemistry
07 Department of Chemistry > Physical Chemistry
Date Deposited: 13 Apr 2018 11:50
DOI: 10.1039/c7tc05023b
Official URL: https://doi.org/10.1039/c7tc05023b
Funders: Qingbo Wen acknowledges the China Scholarship Council (CSC) for financial support (No. 201206130059)., Zhaoju Yu thanks the Natural Science Foundation of Fujian Province of China (No. 2015J01221), the Creative Research Foundation of Science, (No. 6142911040114) and the Alexander von Humboldt Foundation for financial support.
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