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Single-source-precursor synthesis of novel V8C7/SiC(O)-based ceramic nanocomposites

Kaur, Sarabjeet and Cherkashinin, Gennady and Fasel, Claudia and Kleebe, Hans-Joachim and Ionescu, Emanuel and Riedel, Ralf (2016):
Single-source-precursor synthesis of novel V8C7/SiC(O)-based ceramic nanocomposites.
In: Journal of the European Ceramic Society, Elsevier Science Publishing, pp. 3553-3563, 36, (15), ISSN 09552219,
[Online-Edition: http://doi.org/10.1016/j.jeurceramsoc.2016.03.023],
[Article]

Abstract

In the present work, novel V8C7/SiC(O) ceramic nanocomposites were synthesized upon thermal transformation of a polymer-derived single-source-precursor, which was obtained by the chemical modification of a polycarbosilane with vanadyl acetylacetonate. High-temperature treatment of the precursor in argon atmosphere first leads to an amorphous SiVOC single-phase ceramic which subsequently undergoes phase-separation, crystallization and finally converts into V8C7/SiC(O) ceramic nanocomposites. Interestingly, the high-temperature stability of V8C7/SiC(O) was shown to strongly depend on the oxygen content present either in the SiC(O) matrix or in the atmosphere during the annealing process. Thus, larger oxygen contents induce a conversion of the V8C7 phase into V5Si3. The specific surface area (SSA) of the obtained nanocomposite powders depends on the processing temperature: The SSA decreases from 64 to 4 m2/g as the pyrolysis temperature increases from 600 to 1300 °C, respectively. Whereas it increases again to ca. 50 m2/g as the sample is exposed to 1700 °C (6 h annealing), due to the evolution of CO. Preliminary results of the catalytic activity of the V8C7/SiC(O)-based materials show that they are active for the decomposition of the ammonia. The maximum ammonia conversion efficiency was found to be 35% at around 650 °C, which is higher than that of the pure vanadium carbide reported in the literature (ca. 13%).

Item Type: Article
Erschienen: 2016
Creators: Kaur, Sarabjeet and Cherkashinin, Gennady and Fasel, Claudia and Kleebe, Hans-Joachim and Ionescu, Emanuel and Riedel, Ralf
Title: Single-source-precursor synthesis of novel V8C7/SiC(O)-based ceramic nanocomposites
Language: English
Abstract:

In the present work, novel V8C7/SiC(O) ceramic nanocomposites were synthesized upon thermal transformation of a polymer-derived single-source-precursor, which was obtained by the chemical modification of a polycarbosilane with vanadyl acetylacetonate. High-temperature treatment of the precursor in argon atmosphere first leads to an amorphous SiVOC single-phase ceramic which subsequently undergoes phase-separation, crystallization and finally converts into V8C7/SiC(O) ceramic nanocomposites. Interestingly, the high-temperature stability of V8C7/SiC(O) was shown to strongly depend on the oxygen content present either in the SiC(O) matrix or in the atmosphere during the annealing process. Thus, larger oxygen contents induce a conversion of the V8C7 phase into V5Si3. The specific surface area (SSA) of the obtained nanocomposite powders depends on the processing temperature: The SSA decreases from 64 to 4 m2/g as the pyrolysis temperature increases from 600 to 1300 °C, respectively. Whereas it increases again to ca. 50 m2/g as the sample is exposed to 1700 °C (6 h annealing), due to the evolution of CO. Preliminary results of the catalytic activity of the V8C7/SiC(O)-based materials show that they are active for the decomposition of the ammonia. The maximum ammonia conversion efficiency was found to be 35% at around 650 °C, which is higher than that of the pure vanadium carbide reported in the literature (ca. 13%).

Journal or Publication Title: Journal of the European Ceramic Society
Volume: 36
Number: 15
Publisher: Elsevier Science Publishing
Uncontrolled Keywords: V8C7/SiC, Single-source precursor, Polycarbosilane, Polymer-derived ceramic nanocomposites (PDC-NCs)
Divisions: 11 Department of Materials and Earth Sciences > Earth Science > Geo-Material-Science
11 Department of Materials and Earth Sciences > Material Science > Dispersive Solids
11 Department of Materials and Earth Sciences > Material Science > Surface Science
11 Department of Materials and Earth Sciences > Earth Science
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 17 Aug 2016 08:47
Official URL: http://doi.org/10.1016/j.jeurceramsoc.2016.03.023
Additional Information:

Preparation and Application of Ultra-high Temperature Ceramic Matrix Composites

Identification Number: doi:10.1016/j.jeurceramsoc.2016.03.023
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