Yuan, Jia and Hapis, Stefania and Breitzke, Hergen and Xu, Yeping and Fasel, Claudia and Kleebe, Hans-Joachim and Buntkowsky, Gerd and Riedel, Ralf and Ionescu, Emanuel (2014):
Single-Source-Precursor Synthesis of Hafnium-Containing Ultrahigh-Temperature Ceramic Nanocomposites (UHTC-NCs).
In: Inorganic Chemistry, 53 (19), ACS Publications, pp. 10443-10455, ISSN 0020-1669,
[Online-Edition: http://dx.doi.org/10.1021/ic501512p],
[Article]
Abstract
Amorphous SiHfBCN ceramics were prepared from a commercial polysilazane (HTT 1800, AZ-EM), which was modified upon reactions with Hf(NEt2)4 and BH3·SMe2, and subsequently cross-linked and pyrolyzed. The prepared materials were investigated with respect to their chemical and phase composition, by means of spectroscopy techniques (Fourier transform infrared (FTIR), Raman, magic-angle spinning nuclear magnetic resonance (MAS NMR)), as well as X-ray diffraction (XRD) and transmission electron microscopy (TEM). Annealing experiments of the SiHfBCN samples in an inert gas atmosphere (Ar, N2) at temperatures in the range of 1300–1700 °C showed the conversion of the amorphous materials into nanostructured UHTC-NCs. Depending on the annealing atmosphere, HfC/HfB2/SiC (annealing in argon) and HfN/Si3N4/SiBCN (annealing in nitrogen) nanocomposites were obtained. The results emphasize that the conversion of the single-phase SiHfBCN into UHTC-NCs is thermodynamically controlled, thus allowing for a knowledge-based preparative path toward nanostructured ultrahigh-temperature stable materials with adjusted compositions.
| Item Type: | Article |
|---|---|
| Erschienen: | 2014 |
| Creators: | Yuan, Jia and Hapis, Stefania and Breitzke, Hergen and Xu, Yeping and Fasel, Claudia and Kleebe, Hans-Joachim and Buntkowsky, Gerd and Riedel, Ralf and Ionescu, Emanuel |
| Title: | Single-Source-Precursor Synthesis of Hafnium-Containing Ultrahigh-Temperature Ceramic Nanocomposites (UHTC-NCs) |
| Language: | English |
| Abstract: | Amorphous SiHfBCN ceramics were prepared from a commercial polysilazane (HTT 1800, AZ-EM), which was modified upon reactions with Hf(NEt2)4 and BH3·SMe2, and subsequently cross-linked and pyrolyzed. The prepared materials were investigated with respect to their chemical and phase composition, by means of spectroscopy techniques (Fourier transform infrared (FTIR), Raman, magic-angle spinning nuclear magnetic resonance (MAS NMR)), as well as X-ray diffraction (XRD) and transmission electron microscopy (TEM). Annealing experiments of the SiHfBCN samples in an inert gas atmosphere (Ar, N2) at temperatures in the range of 1300–1700 °C showed the conversion of the amorphous materials into nanostructured UHTC-NCs. Depending on the annealing atmosphere, HfC/HfB2/SiC (annealing in argon) and HfN/Si3N4/SiBCN (annealing in nitrogen) nanocomposites were obtained. The results emphasize that the conversion of the single-phase SiHfBCN into UHTC-NCs is thermodynamically controlled, thus allowing for a knowledge-based preparative path toward nanostructured ultrahigh-temperature stable materials with adjusted compositions. |
| Journal or Publication Title: | Inorganic Chemistry |
| Volume: | 53 |
| Number: | 19 |
| Publisher: | ACS Publications |
| 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: | 06 Nov 2014 13:27 |
| Official URL: | http://dx.doi.org/10.1021/ic501512p |
| Identification Number: | doi:10.1021/ic501512p |
| Funders: | .Y. acknowledges fi nancial support from China Scholarship Council (CSC) during his stay at TU Darmstadt., Furthermore, fi nancial support from the European Research Agency (FP7 FUNEA Functional Nitrides for Energy Applications) and the Deutsche Forschungsgemeinschaft (DFG, No. SFB595) is gratefully acknowledged. |
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