TY  - JOUR
AU  - Teppala, Dharma Teja
AU  - Kredel, Samuel Aeneas
AU  - Ionescu, Emanuel
AU  - Matović, Branko
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12864
AB  - Ultra-high temperature ceramics (UHTC) are a class of ceramics that possess melting points greater than 3000 °C and can withstand temperatures higher than 2000 °C without structural failure. The need to increase the performance inherently leads to the implementation of extreme temperatures, leading to the search for a new class of materials with better thermal properties. Compositionally complex ultra-high temperature ceramics with the inclusion of additional elements, whether resulting in an equimolar or non-equimolar site occupation in the respective sublattices, can improve properties due to the contributions of the configurational entropy. The term compositional complexity can be used as an umbrella term for the class of compositions with 3 or more elements and also their non-equimolar parts. The current review paper is based on the classification of the different compositionally complex ultrahigh temperature ceramics as borides, carbides, nitrides, etc., and reviews the different procedures employed for the bulk or powder synthesis thereof.
T2  - Journal of Innovative Materials in Extreme Conditions
T1  - A Review of the Synthesis of Compositionally Complex Ultra-High-Temperature Ceramics
VL  - 4
IS  - 2
SP  - 77
EP  - 103
UR  - https://hdl.handle.net/21.15107/rcub_vinar_12864
ER  - 

@article{
author = "Teppala, Dharma Teja and Kredel, Samuel Aeneas and Ionescu, Emanuel and Matović, Branko",
year = "2023",
abstract = "Ultra-high temperature ceramics (UHTC) are a class of ceramics that possess melting points greater than 3000 °C and can withstand temperatures higher than 2000 °C without structural failure. The need to increase the performance inherently leads to the implementation of extreme temperatures, leading to the search for a new class of materials with better thermal properties. Compositionally complex ultra-high temperature ceramics with the inclusion of additional elements, whether resulting in an equimolar or non-equimolar site occupation in the respective sublattices, can improve properties due to the contributions of the configurational entropy. The term compositional complexity can be used as an umbrella term for the class of compositions with 3 or more elements and also their non-equimolar parts. The current review paper is based on the classification of the different compositionally complex ultrahigh temperature ceramics as borides, carbides, nitrides, etc., and reviews the different procedures employed for the bulk or powder synthesis thereof.",
journal = "Journal of Innovative Materials in Extreme Conditions",
title = "A Review of the Synthesis of Compositionally Complex Ultra-High-Temperature Ceramics",
volume = "4",
number = "2",
pages = "77-103",
url = "https://hdl.handle.net/21.15107/rcub_vinar_12864"
}

Teppala, D. T., Kredel, S. A., Ionescu, E.,& Matović, B.. (2023). A Review of the Synthesis of Compositionally Complex Ultra-High-Temperature Ceramics. in Journal of Innovative Materials in Extreme Conditions, 4(2), 77-103.
https://hdl.handle.net/21.15107/rcub_vinar_12864

Teppala DT, Kredel SA, Ionescu E, Matović B. A Review of the Synthesis of Compositionally Complex Ultra-High-Temperature Ceramics. in Journal of Innovative Materials in Extreme Conditions. 2023;4(2):77-103.
https://hdl.handle.net/21.15107/rcub_vinar_12864 .

Teppala, Dharma Teja, Kredel, Samuel Aeneas, Ionescu, Emanuel, Matović, Branko, "A Review of the Synthesis of Compositionally Complex Ultra-High-Temperature Ceramics" in Journal of Innovative Materials in Extreme Conditions, 4, no. 2 (2023):77-103,
https://hdl.handle.net/21.15107/rcub_vinar_12864 .

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 . .