TY  - JOUR
AU  - Umićević, Ana
AU  - Cekić, Božidar Đ.
AU  - Belošević-Čavor, Jelena
AU  - Koteski, Vasil J.
AU  - Papendorf, Benjamin
AU  - Riedel, Ralf
AU  - Ionescu, Emanuel
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/185
AB  - 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 degrees 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 Si-M-O-C (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. (C) 2014 Elsevier Ltd. All rights reserved.
T2  - Journal of the European Ceramic Society
T1  - Evolution of the local structure at Hf sites in SiHfOC upon ceramization of a hafnium-alkoxide-modified polysilsesquioxane: A perturbed angular correlation study
VL  - 35
IS  - 1
SP  - 29
EP  - 35
DO  - 10.1016/j.jeurceramsoc.2014.08.023
ER  - 

@article{
author = "Umićević, Ana and Cekić, Božidar Đ. and Belošević-Čavor, Jelena and Koteski, Vasil J. and Papendorf, Benjamin and Riedel, Ralf and Ionescu, Emanuel",
year = "2015",
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 degrees 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 Si-M-O-C (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. (C) 2014 Elsevier Ltd. All rights reserved.",
journal = "Journal of the European Ceramic Society",
title = "Evolution of the local structure at Hf sites in SiHfOC upon ceramization of a hafnium-alkoxide-modified polysilsesquioxane: A perturbed angular correlation study",
volume = "35",
number = "1",
pages = "29-35",
doi = "10.1016/j.jeurceramsoc.2014.08.023"
}

Umićević, A., Cekić, B. Đ., Belošević-Čavor, J., Koteski, V. J., Papendorf, B., Riedel, R.,& Ionescu, E.. (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), 29-35.
https://doi.org/10.1016/j.jeurceramsoc.2014.08.023

Umićević A, Cekić BĐ, Belošević-Čavor J, Koteski VJ, Papendorf B, Riedel R, Ionescu E. 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. 2015;35(1):29-35.
doi:10.1016/j.jeurceramsoc.2014.08.023 .

Umićević, Ana, Cekić, Božidar Đ., Belošević-Čavor, Jelena, Koteski, Vasil J., Papendorf, Benjamin, Riedel, Ralf, Ionescu, Emanuel, "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, no. 1 (2015):29-35,
https://doi.org/10.1016/j.jeurceramsoc.2014.08.023 . .