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Evolution of the local structure at Hf sites in SiHfOC upon ceramization of a hafnium-alkoxide-modified polysilsesquioxane: A perturbed angular correlation study

Umićević, Ana B. and Cekić, Božidar Đ. and Belošević-Čavor, Jelena N. and Koteski, Vasil J. and Papendorf, Benjamin and Riedel, Ralf and Ionescu, Emanuel (2015):
Evolution of the local structure at Hf sites in SiHfOC upon ceramization of a hafnium-alkoxide-modified polysilsesquioxane: A perturbed angular correlation study.
In: Journal of the European Ceramic Society, 35 (1), Elsevier Science Publishing, pp. 29-35, ISSN 09552219,
[Online-Edition: http://dx.doi.org/10.1016/j.jeurceramsoc.2014.08.023],
[Article]

Abstract

The evolution of the environment of Hf sites in a hafnium-alkoxide-modified polysilsesquioxane upon polymer-to-ceramic transformation was investigated via the perturbed angular correlation (PAC) method. The results of the PAC measurements on samples thermally treated at temperatures from 400 to 1300 °C indicate that Hf is surrounded only by oxygen at all studied temperatures. This finding is in agreement with the evolution pathway of polymer-derived SiHfOC ceramics, which were reported to be generated as single-phase amorphous materials upon pyrolysis of alkoxide-modified polysiloxanes and subsequently to phase separate and crystallize towards HfO2/SiOC nanocomposites. Thus, the results presented here support our previous statement that there is a thermodynamic control on the phase separation and crystallization behavior of Sisingle bondMsingle bondOsingle bondC (M = metal) ceramics (Ionescu et al. 96;2013:1899–1903), which in the case of Hf leads to the precipitation and crystallization of hafnia nanoparticles within a SiOC matrix.

Item Type: Article
Erschienen: 2015
Creators: Umićević, Ana B. and Cekić, Božidar Đ. and Belošević-Čavor, Jelena N. and Koteski, Vasil J. and Papendorf, Benjamin and Riedel, Ralf and Ionescu, Emanuel
Title: Evolution of the local structure at Hf sites in SiHfOC upon ceramization of a hafnium-alkoxide-modified polysilsesquioxane: A perturbed angular correlation study
Language: English
Abstract:

The evolution of the environment of Hf sites in a hafnium-alkoxide-modified polysilsesquioxane upon polymer-to-ceramic transformation was investigated via the perturbed angular correlation (PAC) method. The results of the PAC measurements on samples thermally treated at temperatures from 400 to 1300 °C indicate that Hf is surrounded only by oxygen at all studied temperatures. This finding is in agreement with the evolution pathway of polymer-derived SiHfOC ceramics, which were reported to be generated as single-phase amorphous materials upon pyrolysis of alkoxide-modified polysiloxanes and subsequently to phase separate and crystallize towards HfO2/SiOC nanocomposites. Thus, the results presented here support our previous statement that there is a thermodynamic control on the phase separation and crystallization behavior of Sisingle bondMsingle bondOsingle bondC (M = metal) ceramics (Ionescu et al. 96;2013:1899–1903), which in the case of Hf leads to the precipitation and crystallization of hafnia nanoparticles within a SiOC matrix.

Journal or Publication Title: Journal of the European Ceramic Society
Volume: 35
Number: 1
Publisher: Elsevier Science Publishing
Uncontrolled Keywords: Polymer-derived ceramics (PDCs), Perturbed angular correlation (PAC); HfO2/SiOC nanocomposites, Polymer-to-ceramic transformation, Nanostructure evolution
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 13:17
Official URL: http://dx.doi.org/10.1016/j.jeurceramsoc.2014.08.023
Identification Number: doi:10.1016/j.jeurceramsoc.2014.08.023
Funders: The Ministry of Education, Science and Technological Development of the Republic of Serbia (Project no. 171001) provided the financial support for this study through the project no. 171001., EI and RR thank to the German Science Foundation (DFG) (DFG: IO 64/7-1) for financial support.
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