Fahrenholtz, William

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  • Fahrenholtz, William (1)
  • Fahrenholtz, William G. (1)

Author's Bibliography

Spark plasma sintering of magnesium titanate ceramics

Filipović, Suzana; Obradović, Nina; Fahrenholtz, William; Smith, Steven; Mirković, Miljana M.; Peleš Tadić, Adriana; Petrović, Jovana; Đorđević, Antonije

(2024)

TY  - JOUR
AU  - Filipović, Suzana
AU  - Obradović, Nina
AU  - Fahrenholtz, William
AU  - Smith, Steven
AU  - Mirković, Miljana M.
AU  - Peleš Tadić, Adriana
AU  - Petrović, Jovana
AU  - Đorđević, Antonije
PY  - 2024
UR  - https://dais.sanu.ac.rs/123456789/16383
AB  - Magnesium titanate ceramics were prepared by reactive spark plasma sintering (SPS) at 1200 °C for 5 min. Prior to sintering, MgO and TiO2 powders were mixed by high energy ball milling (HEBM) for 15, 30, or 60 min. The effect of milling time on phase composition was analyzed by X-ray diffraction (XRD) for milled powders and sintered specimens. The morphology of the sintered ceramics was investigated by scanning electron microscopy (SEM), while elemental distribution was determined by energy dispersive spectroscopy (EDS). The presence of the MgTi2O5 phase was detected in XRD and was confirmed by EDS analysis. Microcracking was observed for specimens prepared with longer milling times and attributed to the coefficient of thermal expansion (CTE) mismatch dominantly due to the anisotropic crystal structure of MgTiO3 phase. The sample milled for 15 min showed the highest Vickers hardness due to less or no microcracking and nearly full density. The dielectric measurements in the range of 10 Hz–250 MHz demonstrated extremely high dielectric permittivity, as high as 104 at 1 kHz. An increase in loss tangents was observed due to oxygen vacancy formation, which was promoted by the vacuum environment during SPS. Oxygen vacancy-related dielectric relaxation was also detected and explained.
T2  - Ceramics International
T1  - Spark plasma sintering of magnesium titanate ceramics
DO  - 10.1016/j.ceramint.2024.02.004
UR  - https://hdl.handle.net/21.15107/rcub_dais_16383
ER  - 
@article{
author = "Filipović, Suzana and Obradović, Nina and Fahrenholtz, William and Smith, Steven and Mirković, Miljana M. and Peleš Tadić, Adriana and Petrović, Jovana and Đorđević, Antonije",
year = "2024",
abstract = "Magnesium titanate ceramics were prepared by reactive spark plasma sintering (SPS) at 1200 °C for 5 min. Prior to sintering, MgO and TiO2 powders were mixed by high energy ball milling (HEBM) for 15, 30, or 60 min. The effect of milling time on phase composition was analyzed by X-ray diffraction (XRD) for milled powders and sintered specimens. The morphology of the sintered ceramics was investigated by scanning electron microscopy (SEM), while elemental distribution was determined by energy dispersive spectroscopy (EDS). The presence of the MgTi2O5 phase was detected in XRD and was confirmed by EDS analysis. Microcracking was observed for specimens prepared with longer milling times and attributed to the coefficient of thermal expansion (CTE) mismatch dominantly due to the anisotropic crystal structure of MgTiO3 phase. The sample milled for 15 min showed the highest Vickers hardness due to less or no microcracking and nearly full density. The dielectric measurements in the range of 10 Hz–250 MHz demonstrated extremely high dielectric permittivity, as high as 104 at 1 kHz. An increase in loss tangents was observed due to oxygen vacancy formation, which was promoted by the vacuum environment during SPS. Oxygen vacancy-related dielectric relaxation was also detected and explained.",
journal = "Ceramics International",
title = "Spark plasma sintering of magnesium titanate ceramics",
doi = "10.1016/j.ceramint.2024.02.004",
url = "https://hdl.handle.net/21.15107/rcub_dais_16383"
}
Filipović, S., Obradović, N., Fahrenholtz, W., Smith, S., Mirković, M. M., Peleš Tadić, A., Petrović, J.,& Đorđević, A.. (2024). Spark plasma sintering of magnesium titanate ceramics. in Ceramics International.
https://doi.org/10.1016/j.ceramint.2024.02.004
https://hdl.handle.net/21.15107/rcub_dais_16383
Filipović S, Obradović N, Fahrenholtz W, Smith S, Mirković MM, Peleš Tadić A, Petrović J, Đorđević A. Spark plasma sintering of magnesium titanate ceramics. in Ceramics International. 2024;.
doi:10.1016/j.ceramint.2024.02.004
https://hdl.handle.net/21.15107/rcub_dais_16383 .
Filipović, Suzana, Obradović, Nina, Fahrenholtz, William, Smith, Steven, Mirković, Miljana M., Peleš Tadić, Adriana, Petrović, Jovana, Đorđević, Antonije, "Spark plasma sintering of magnesium titanate ceramics" in Ceramics International (2024),
https://doi.org/10.1016/j.ceramint.2024.02.004 .,
https://hdl.handle.net/21.15107/rcub_dais_16383 .

Characterization of MgAl2O4 sintered ceramics

Obradović, Nina; Fahrenholtz, William G.; Filipović, Suzana; Đorđević, Pavle; Marković, Smilja; Rogan, Jelena; Vulić, Predrag J.; Pavlović, Vladimir B.

(Belgrade : Serbian Ceramic Society, 2019)

TY  - CONF
AU  - Obradović, Nina
AU  - Fahrenholtz, William G.
AU  - Filipović, Suzana
AU  - Đorđević, Pavle
AU  - Marković, Smilja
AU  - Rogan, Jelena
AU  - Vulić, Predrag J.
AU  - Pavlović, Vladimir B.
PY  - 2019
UR  - https://dais.sanu.ac.rs/123456789/6980
AB  - Single crystalline phase MgAl2O4 is made from the predetermined composition of MgO-Al2O3 powder mixture by using ball-milling. Mixtures of MgO and Al2O3 are treated in planetary ball mill for 30, 60, 90 and 120 minutes, in air. The aim of this experiment was to examine phase composition, microstructure, and densification behavior of all sintered samples and to find out which sample has the best features for further use. After sintering in dilatometer at 1500 °C, XRD patterns and SEM images were recorded. The results show that mechanical activation is an efficient method to improve the densification behavior of MgAl2O4 sintered specimens. With the prolonged milling time, densities increased, reaching the maximum value of 2.8 g/cm3 for sample activated 120 minutes.
PB  - Belgrade : Serbian Ceramic Society
C3  - Program and the Book of abstracts / Serbian Ceramic Society Conference Advanced Ceramics and Application VIII : New Frontiers in Multifunctional Material Science and Processing, Serbia, Belgrade, 23-25. September 2019
T1  - Characterization of MgAl2O4 sintered ceramics
SP  - 54
EP  - 54
UR  - https://hdl.handle.net/21.15107/rcub_dais_6980
ER  - 
@conference{
author = "Obradović, Nina and Fahrenholtz, William G. and Filipović, Suzana and Đorđević, Pavle and Marković, Smilja and Rogan, Jelena and Vulić, Predrag J. and Pavlović, Vladimir B.",
year = "2019",
abstract = "Single crystalline phase MgAl2O4 is made from the predetermined composition of MgO-Al2O3 powder mixture by using ball-milling. Mixtures of MgO and Al2O3 are treated in planetary ball mill for 30, 60, 90 and 120 minutes, in air. The aim of this experiment was to examine phase composition, microstructure, and densification behavior of all sintered samples and to find out which sample has the best features for further use. After sintering in dilatometer at 1500 °C, XRD patterns and SEM images were recorded. The results show that mechanical activation is an efficient method to improve the densification behavior of MgAl2O4 sintered specimens. With the prolonged milling time, densities increased, reaching the maximum value of 2.8 g/cm3 for sample activated 120 minutes.",
publisher = "Belgrade : Serbian Ceramic Society",
journal = "Program and the Book of abstracts / Serbian Ceramic Society Conference Advanced Ceramics and Application VIII : New Frontiers in Multifunctional Material Science and Processing, Serbia, Belgrade, 23-25. September 2019",
title = "Characterization of MgAl2O4 sintered ceramics",
pages = "54-54",
url = "https://hdl.handle.net/21.15107/rcub_dais_6980"
}
Obradović, N., Fahrenholtz, W. G., Filipović, S., Đorđević, P., Marković, S., Rogan, J., Vulić, P. J.,& Pavlović, V. B.. (2019). Characterization of MgAl2O4 sintered ceramics. in Program and the Book of abstracts / Serbian Ceramic Society Conference Advanced Ceramics and Application VIII : New Frontiers in Multifunctional Material Science and Processing, Serbia, Belgrade, 23-25. September 2019
Belgrade : Serbian Ceramic Society., 54-54.
https://hdl.handle.net/21.15107/rcub_dais_6980
Obradović N, Fahrenholtz WG, Filipović S, Đorđević P, Marković S, Rogan J, Vulić PJ, Pavlović VB. Characterization of MgAl2O4 sintered ceramics. in Program and the Book of abstracts / Serbian Ceramic Society Conference Advanced Ceramics and Application VIII : New Frontiers in Multifunctional Material Science and Processing, Serbia, Belgrade, 23-25. September 2019. 2019;:54-54.
https://hdl.handle.net/21.15107/rcub_dais_6980 .
Obradović, Nina, Fahrenholtz, William G., Filipović, Suzana, Đorđević, Pavle, Marković, Smilja, Rogan, Jelena, Vulić, Predrag J., Pavlović, Vladimir B., "Characterization of MgAl2O4 sintered ceramics" in Program and the Book of abstracts / Serbian Ceramic Society Conference Advanced Ceramics and Application VIII : New Frontiers in Multifunctional Material Science and Processing, Serbia, Belgrade, 23-25. September 2019 (2019):54-54,
https://hdl.handle.net/21.15107/rcub_dais_6980 .