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Obradović, Nina

Link to this page

Authority KeyName Variants
orcid::0000-0002-7993-293X
  • Obradović, Nina (166)
Projects
Directed synthesis, structure and properties of multifunctional materials Investigation of the relation in triad: Synthesis structure-properties for functional materials
Ministry of Education, Youth and Sports (MEYS) of Czech Republic - CEITEC 2020 [LQ1601] Development and application of multifunctional materials using domestic raw materials in upgraded processing lines
United States National Aeronautics and Space Administration (NASA), Grant NNX09AV07A Serbian Academy of Sciences and Arts, Project F-198
Synthesis, processing and applications of nanostructured multifunctional materials with defined properties Algorithms and software for frequency-domain and time-domain simulations of RF subsystems and electromagnetic sensors in ICT
United States National Science Foundation (NSF) / Centers of Research Excellence in Science and Technology (CREST), Grant HRD-0833184 Bilateral cooperation between Serbia and France, No. 4510339/2016/09/03 “Inteligent econanomaterials and nanocomposites”
Grant Agency of the Czech Republic, Project 15-06390S Zero- to Three-Dimensional Nanostructures for Application in Electronics and Renewable Energy Sources: Synthesis, Characterization and Processing
National Science Foundation, North Carolina State University, Project No. HRD-1345219 United States National Science Foundation (NSF) / Partnerships for Research and Education in Materials (PREM), Grant 1523617
Czech Science Foundation (GACR) - 17-05620S Investigation of intermetallics and semiconductors and possible application in renewable energy sources
Geologic and ecotoxicologic research in identification of geopathogen zones of toxic elements in drinking water reservoirs- research into methods and procedures for reduction of biochemical anomalies Brno University of Technology - BUT Internal Projects: STI-J-18-5456, Czechia
CEITEC Nano RI, MEYS CR, 2016–2019 CONACYT grant 2018-000022-01EXTV-00188, Mexico
DAAD scholarship project "Development of materials and manufacturing technologies for electric discharge machinable Zirconia–CNT/Graphene composites" Innovative electronic components and systems based on inorganic and organic technologies embedded in consumer goods and products
Serbian Academy of Sciences and Arts, Project F-7/II Austrian Federal Funding Agency (FFG), MagnetoPIM (programme CIR-CE - Cooperation in Innovation and Research with Central and Eastern Europe)
European Regional Development Fund through a project CEITEC, CZ.1.05/1.1.00/02.0068 Functional, Functionalized and Advanced Nanomaterials
Synthesis, processing and characterization of nanostructured materials for application in the field of energy, mechanical engineering, environmental protection and biomedicine Develooment and utilization of novel and traditional technologies in production of competitive food products with added valued for national and global market - CREATING WEALTH FROM THE WEALTH OF SERBIA
Novel encapsulation and enzyme technologies for designing of new biocatalysts and biologically active compounds targeting enhancement of food quality, safety and competitiveness Razvoj i primena metoda za praćenje kvaliteta industrijskih proizvoda i životne sredine

Author's Bibliography

Formation kinetics and cation inversion in mechanically activated MgAl2O4 spinel ceramics

Obradović, Nina; Fahrenholtz, William G.; Filipović, Suzana; Marković, Smilja; Blagojević, Vladimir A.; Lević, Steva; Savić, Slobodan; Đorđević, Antonije; Pavlović, Vladimir B.

(Springer, 2020)

TY  - JOUR
AU  - Obradović, Nina
AU  - Fahrenholtz, William G.
AU  - Filipović, Suzana
AU  - Marković, Smilja
AU  - Blagojević, Vladimir A.
AU  - Lević, Steva
AU  - Savić, Slobodan
AU  - Đorđević, Antonije
AU  - Pavlović, Vladimir B.
PY  - 2020
UR  - http://dais.sanu.ac.rs/123456789/6910
AB  - Solid-state mechanical activation of MgO and α-Al2O3 powders was used to produce MgAl2O4. The cation site occupancy in the resulting MgAl2O4 spinel was investigated using different methods. Differential thermal analysis and thermal gravimetry showed that mechanical activation reduced the spinel formation temperature by around 200 °C, and the corresponding activation energy by about 25%. In addition, characteristic temperatures for evaporation of physisorbed water and decomposition of Mg(OH)2 shifted to lower values, and peaks were more pronounced. Raman spectra were used to characterize the degree of inversion as a function of the sintering temperature for all of the sintered specimens, indicating that the breaking point for ordering of the crystal structure was around 1500 °C for non-activated samples, and 1400 °C for activated samples.
PB  - Springer
T2  - Journal of Thermal Analysis and Calorimetry
T1  - Formation kinetics and cation inversion in mechanically activated MgAl2O4 spinel ceramics
DO  - 10.1007/s10973-019-08846-w
ER  - 
@article{
author = "Obradović, Nina and Fahrenholtz, William G. and Filipović, Suzana and Marković, Smilja and Blagojević, Vladimir A. and Lević, Steva and Savić, Slobodan and Đorđević, Antonije and Pavlović, Vladimir B.",
year = "2020",
url = "http://dais.sanu.ac.rs/123456789/6910",
abstract = "Solid-state mechanical activation of MgO and α-Al2O3 powders was used to produce MgAl2O4. The cation site occupancy in the resulting MgAl2O4 spinel was investigated using different methods. Differential thermal analysis and thermal gravimetry showed that mechanical activation reduced the spinel formation temperature by around 200 °C, and the corresponding activation energy by about 25%. In addition, characteristic temperatures for evaporation of physisorbed water and decomposition of Mg(OH)2 shifted to lower values, and peaks were more pronounced. Raman spectra were used to characterize the degree of inversion as a function of the sintering temperature for all of the sintered specimens, indicating that the breaking point for ordering of the crystal structure was around 1500 °C for non-activated samples, and 1400 °C for activated samples.",
publisher = "Springer",
journal = "Journal of Thermal Analysis and Calorimetry",
title = "Formation kinetics and cation inversion in mechanically activated MgAl2O4 spinel ceramics",
doi = "10.1007/s10973-019-08846-w"
}
1
1
2

Robocasting of controlled porous CaSiO3–SiO2 structures: Architecture – Strength relationship and material catalytic behavior

Casas-Luna, Mariano; Torres-Rodríguez, Jorge Alberto; Valdés-Martínez, Omar Uriel; Obradović, Nina; Slámečka, Karel; Maca, Karel; Kaiser, Jozef; Montúfar, Edgar B.; Čelko, Ladislav

(Elsevier, 2020)

TY  - JOUR
AU  - Casas-Luna, Mariano
AU  - Torres-Rodríguez, Jorge Alberto
AU  - Valdés-Martínez, Omar Uriel
AU  - Obradović, Nina
AU  - Slámečka, Karel
AU  - Maca, Karel
AU  - Kaiser, Jozef
AU  - Montúfar, Edgar B.
AU  - Čelko, Ladislav
PY  - 2020
UR  - https://linkinghub.elsevier.com/retrieve/pii/S027288421933620X
UR  - http://dais.sanu.ac.rs/123456789/8943
AB  - Wollastonite (CaSiO3) based porous structures are useful in a wide range of applications including catalysis. Furthermore, the use of additive manufac…
PB  - Elsevier
T2  - Ceramics International
T1  - Robocasting of controlled porous CaSiO3–SiO2 structures: Architecture – Strength relationship and material catalytic behavior
SP  - 8853
EP  - 8861
VL  - 46
IS  - 7
DO  - 10.1016/j.ceramint.2019.12.130
ER  - 
@article{
author = "Casas-Luna, Mariano and Torres-Rodríguez, Jorge Alberto and Valdés-Martínez, Omar Uriel and Obradović, Nina and Slámečka, Karel and Maca, Karel and Kaiser, Jozef and Montúfar, Edgar B. and Čelko, Ladislav",
year = "2020",
url = "https://linkinghub.elsevier.com/retrieve/pii/S027288421933620X, http://dais.sanu.ac.rs/123456789/8943",
abstract = "Wollastonite (CaSiO3) based porous structures are useful in a wide range of applications including catalysis. Furthermore, the use of additive manufac…",
publisher = "Elsevier",
journal = "Ceramics International",
title = "Robocasting of controlled porous CaSiO3–SiO2 structures: Architecture – Strength relationship and material catalytic behavior",
pages = "8853-8861",
volume = "46",
number = "7",
doi = "10.1016/j.ceramint.2019.12.130"
}
1
1

Robocasting of controlled porous CaSiO3–SiO2 structures: Architecture – Strength relationship and material catalytic behavior

Casas-Luna, Mariano; Torres-Rodríguez, Jorge Alberto; Valdés-Martínez, Omar Uriel; Obradović, Nina; Slámečka, Karel; Maca, Karel; Kaiser, Jozef; Montúfar, Edgar B.; Čelko, Ladislav

(Elsevier, 2020)

TY  - JOUR
AU  - Casas-Luna, Mariano
AU  - Torres-Rodríguez, Jorge Alberto
AU  - Valdés-Martínez, Omar Uriel
AU  - Obradović, Nina
AU  - Slámečka, Karel
AU  - Maca, Karel
AU  - Kaiser, Jozef
AU  - Montúfar, Edgar B.
AU  - Čelko, Ladislav
PY  - 2020
UR  - https://linkinghub.elsevier.com/retrieve/pii/S027288421933620X
UR  - http://dais.sanu.ac.rs/123456789/6942
AB  - Wollastonite (CaSiO3) based porous structures are useful in a wide range of applications including catalysis. Furthermore, the use of additive manufac…
PB  - Elsevier
T2  - Ceramics International
T1  - Robocasting of controlled porous CaSiO3–SiO2 structures: Architecture – Strength relationship and material catalytic behavior
SP  - 8853
EP  - 8861
VL  - 46
IS  - 7
DO  - 10.1016/j.ceramint.2019.12.130
ER  - 
@article{
author = "Casas-Luna, Mariano and Torres-Rodríguez, Jorge Alberto and Valdés-Martínez, Omar Uriel and Obradović, Nina and Slámečka, Karel and Maca, Karel and Kaiser, Jozef and Montúfar, Edgar B. and Čelko, Ladislav",
year = "2020",
url = "https://linkinghub.elsevier.com/retrieve/pii/S027288421933620X, http://dais.sanu.ac.rs/123456789/6942",
abstract = "Wollastonite (CaSiO3) based porous structures are useful in a wide range of applications including catalysis. Furthermore, the use of additive manufac…",
publisher = "Elsevier",
journal = "Ceramics International",
title = "Robocasting of controlled porous CaSiO3–SiO2 structures: Architecture – Strength relationship and material catalytic behavior",
pages = "8853-8861",
volume = "46",
number = "7",
doi = "10.1016/j.ceramint.2019.12.130"
}
1
1

The effect of ball milling on properties of sintered manganese-doped alumina

Filipović, Suzana; Obradović, Nina; Marković, Smilja; Mitrić, Miodrag; Balać, Igor; Đorđević, Antonije; Pavlović, Vladimir B.

(Elsevier, 2019)

TY  - JOUR
AU  - Filipović, Suzana
AU  - Obradović, Nina
AU  - Marković, Smilja
AU  - Mitrić, Miodrag
AU  - Balać, Igor
AU  - Đorđević, Antonije
AU  - Pavlović, Vladimir B.
PY  - 2019
UR  - http://www.sciencedirect.com/science/article/pii/S0921883119302596
UR  - http://dais.sanu.ac.rs/123456789/6951
AB  - Alumina-based compounds have many technological applications and attract great attention even after decades of investigation, due to their good chemical, electrical, and mechanical properties. A mixture of several alumina modifications (α-, κ-, γ-Al2O3) doped with 1 wt% of Mn2O3 was used for this experiment. The powder was mechanically activated for 60 min in an ethanol medium. After compaction, green bodies were sintered in the temperature range from 1200 to 1400 °C. Microstructures of the obtained specimens were investigated by scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS). The influence of morphological changes on electrical and mechanical properties was examined in detail. We have developed a test fixture and corresponding software for measurement of the relative dielectric permittivity and the loss tangent of ceramic specimens. This new method overcomes the problems of dimensions and shape of samples, as well as the problem of applying silver paste. The accuracy is around 2% for ε'r and 0.003 for tanδ. We demonstrate that the mechanical activation (MA) has the dominant influence on lowering the characteristic temperatures and microstructure development, which further leads to increased permittivity and tensile strength.
PB  - Elsevier
T2  - Advanced Powder Technology
T1  - The effect of ball milling on properties of sintered manganese-doped alumina
SP  - 2533
EP  - 2540
VL  - 30
IS  - 11
DO  - 10.1016/j.apt.2019.07.033
ER  - 
@article{
author = "Filipović, Suzana and Obradović, Nina and Marković, Smilja and Mitrić, Miodrag and Balać, Igor and Đorđević, Antonije and Pavlović, Vladimir B.",
year = "2019",
url = "http://www.sciencedirect.com/science/article/pii/S0921883119302596, http://dais.sanu.ac.rs/123456789/6951",
abstract = "Alumina-based compounds have many technological applications and attract great attention even after decades of investigation, due to their good chemical, electrical, and mechanical properties. A mixture of several alumina modifications (α-, κ-, γ-Al2O3) doped with 1 wt% of Mn2O3 was used for this experiment. The powder was mechanically activated for 60 min in an ethanol medium. After compaction, green bodies were sintered in the temperature range from 1200 to 1400 °C. Microstructures of the obtained specimens were investigated by scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS). The influence of morphological changes on electrical and mechanical properties was examined in detail. We have developed a test fixture and corresponding software for measurement of the relative dielectric permittivity and the loss tangent of ceramic specimens. This new method overcomes the problems of dimensions and shape of samples, as well as the problem of applying silver paste. The accuracy is around 2% for ε'r and 0.003 for tanδ. We demonstrate that the mechanical activation (MA) has the dominant influence on lowering the characteristic temperatures and microstructure development, which further leads to increased permittivity and tensile strength.",
publisher = "Elsevier",
journal = "Advanced Powder Technology",
title = "The effect of ball milling on properties of sintered manganese-doped alumina",
pages = "2533-2540",
volume = "30",
number = "11",
doi = "10.1016/j.apt.2019.07.033"
}
2
1

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  - http://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
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",
url = "http://dais.sanu.ac.rs/123456789/6980",
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"
}

Influence of mechanical activation on kinetics and formation of spinel monitored by DTA

Obradović, Nina; Fahrenholtz, William G.; Filipović, Suzana; Marković, Smilja; Blagojević, Vladimir A.; Lević, Steva; Đorđević, Antonije; Pavlović, Vladimir B.

(Central and Eastern European Committee for Thermal Analysis and Calorimetry, 2019)

TY  - CONF
AU  - Obradović, Nina
AU  - Fahrenholtz, William G.
AU  - Filipović, Suzana
AU  - Marković, Smilja
AU  - Blagojević, Vladimir A.
AU  - Lević, Steva
AU  - Đorđević, Antonije
AU  - Pavlović, Vladimir B.
PY  - 2019
UR  - http://dais.sanu.ac.rs/123456789/7020
AB  - Magnesium aluminate and other alumina-based spinels are refractory ceramics with excellent properties, such as high hardness, high mechanical strength, and low dielectric constant, applicable in many modern industries. MgAl2O4 was produced by solid state reaction between MgO and alpha-Al2O3 powders. Mechanical activation represents a very efficient method for increasing the reactivity of powders, accelerating chemical reactions and decreasing the sintering temperatures. Mechanical activation of mixed powders was performed in a high-energy planetary ball mill in air for 60 minutes. Sintering was performed in air at temperatures ranging from 1200°C to 1600 °C with a 2 h dwell time. Initial powders and sintered samples were characterized using X-ray diffraction and scanning electron microscopy. Differential thermal analysis (DTA) and thermal gravimetry (TG) were used to determine the temperatures for synthesis reactions and phase transformations. Based on the DTA results, several different processes occured during heating, including evaporation of physisorbed water, decomposition of Mg(OH)2, and spinel formation. With mechanical activation, all characteristic temperatures shifted to lower values, and peaks were more pronounced. Raman spectra were used to characterize the degree of inversion as a function of sintering temperature for all of the sintered specimens.
PB  - Central and Eastern European Committee for Thermal Analysis and Calorimetry
C3  - Book of abstracts of the 5th Central and Eastern European Conference on Thermal Analysis and Calorimetry (CEEC-TAC5) and 14th Mediterranean Conference on Calorimetry and Thermal Analysis (Medicta2019)
T1  - Influence of mechanical activation on kinetics and formation of spinel monitored by DTA
SP  - 70
EP  - 70
ER  - 
@conference{
author = "Obradović, Nina and Fahrenholtz, William G. and Filipović, Suzana and Marković, Smilja and Blagojević, Vladimir A. and Lević, Steva and Đorđević, Antonije and Pavlović, Vladimir B.",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/7020",
abstract = "Magnesium aluminate and other alumina-based spinels are refractory ceramics with excellent properties, such as high hardness, high mechanical strength, and low dielectric constant, applicable in many modern industries. MgAl2O4 was produced by solid state reaction between MgO and alpha-Al2O3 powders. Mechanical activation represents a very efficient method for increasing the reactivity of powders, accelerating chemical reactions and decreasing the sintering temperatures. Mechanical activation of mixed powders was performed in a high-energy planetary ball mill in air for 60 minutes. Sintering was performed in air at temperatures ranging from 1200°C to 1600 °C with a 2 h dwell time. Initial powders and sintered samples were characterized using X-ray diffraction and scanning electron microscopy. Differential thermal analysis (DTA) and thermal gravimetry (TG) were used to determine the temperatures for synthesis reactions and phase transformations. Based on the DTA results, several different processes occured during heating, including evaporation of physisorbed water, decomposition of Mg(OH)2, and spinel formation. With mechanical activation, all characteristic temperatures shifted to lower values, and peaks were more pronounced. Raman spectra were used to characterize the degree of inversion as a function of sintering temperature for all of the sintered specimens.",
publisher = "Central and Eastern European Committee for Thermal Analysis and Calorimetry",
journal = "Book of abstracts of the 5th Central and Eastern European Conference on Thermal Analysis and Calorimetry (CEEC-TAC5) and 14th Mediterranean Conference on Calorimetry and Thermal Analysis (Medicta2019)",
title = "Influence of mechanical activation on kinetics and formation of spinel monitored by DTA",
pages = "70-70"
}

Electrical and mechanical properties of alumina doped with transition metal oxides sintered at 1400°C

Filipović, Suzana; Obradović, Nina; Marković, Smilja; Balać, Igor; Đorđević, Antonije; Pavlović, Vladimir B.

(Societa ceramica italiana, 2019)

TY  - CONF
AU  - Filipović, Suzana
AU  - Obradović, Nina
AU  - Marković, Smilja
AU  - Balać, Igor
AU  - Đorđević, Antonije
AU  - Pavlović, Vladimir B.
PY  - 2019
UR  - http://dais.sanu.ac.rs/123456789/7025
AB  - Corundum (alpha-alumina) is one of the most exploited materials in ceramic industry due to its good physico-chemical properties, mechanical properties, and, importantly, due to its low cost. Advantageous properties, such as hardness, dielectric and thermal properties, and refractoriness, open the door to a wide range of applications of corundum. Porous alumina ceramics is often used for filters and as a catalytic substrate, whereas dense alumina ceramics is frequently used in automotive and aerospace industry. Hence, there is a great interest in exploring this type of ceramics. The aim of this work is to explain the influence of preparation parameters (mechanical activation, addition of transition metal oxides, and sintering conditions) on the final electrical and mechanical properties of alumina. 
As a starting powder, a mix of a few alumina modifications (α-, κ-,γ - Al2O3) was used. It was doped with 1 wt % of Mn2O3, Cr2O3, and NiO, respectively. Three of the obtained mixtures were homogenized and three were ball milled for 60 min. Particle size analysis, SEM, and EDS were performed in order to demonstrate changes in the microstructure after milling. DTA/TG analyses were used to determine all characteristic temperatures. After sintering at 1400 oC in an air atmosphere, mechanical, electrical, and physico-chemical properties of the obtained ceramics were determined. 
Results showed that the mechanical treatment lead to a decrease in temperatures of phase transitions and sintering for approximately 100 oC. Incorporation of cations of transition metals into the crystal lattice of alumina was noticed. Activated and sintered samples showed a higher tensile strength and higher relative dielectric permittivity then the sample doped with Cr2O3. 
The main conclusion of this investigation is that the mechanical activation has the dominant influence on lowering the characteristic temperatures of all detected phase transitions and sintering processes. Using a mixture of several crystalline phases of alumina as a starting powder alleviates the incorporation of transition-metal cations into the alumina crystal lattice, leading to changes in microstructures of the prepared ceramics. Finally, changes in the microstructure and lattice disordering have the dominant influence on the final mechanical properties.
PB  - Societa ceramica italiana
PB  - Politecnico di Torino
C3  - Abstract Book / XVI Conference and Exhibition of the European Ceramic Society XVI ECerS Conference, Torino, 16-20 June 2019
T1  - Electrical and mechanical properties of alumina doped with transition metal oxides sintered at 1400°C
SP  - 682
EP  - 682
ER  - 
@conference{
author = "Filipović, Suzana and Obradović, Nina and Marković, Smilja and Balać, Igor and Đorđević, Antonije and Pavlović, Vladimir B.",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/7025",
abstract = "Corundum (alpha-alumina) is one of the most exploited materials in ceramic industry due to its good physico-chemical properties, mechanical properties, and, importantly, due to its low cost. Advantageous properties, such as hardness, dielectric and thermal properties, and refractoriness, open the door to a wide range of applications of corundum. Porous alumina ceramics is often used for filters and as a catalytic substrate, whereas dense alumina ceramics is frequently used in automotive and aerospace industry. Hence, there is a great interest in exploring this type of ceramics. The aim of this work is to explain the influence of preparation parameters (mechanical activation, addition of transition metal oxides, and sintering conditions) on the final electrical and mechanical properties of alumina. 
As a starting powder, a mix of a few alumina modifications (α-, κ-,γ - Al2O3) was used. It was doped with 1 wt % of Mn2O3, Cr2O3, and NiO, respectively. Three of the obtained mixtures were homogenized and three were ball milled for 60 min. Particle size analysis, SEM, and EDS were performed in order to demonstrate changes in the microstructure after milling. DTA/TG analyses were used to determine all characteristic temperatures. After sintering at 1400 oC in an air atmosphere, mechanical, electrical, and physico-chemical properties of the obtained ceramics were determined. 
Results showed that the mechanical treatment lead to a decrease in temperatures of phase transitions and sintering for approximately 100 oC. Incorporation of cations of transition metals into the crystal lattice of alumina was noticed. Activated and sintered samples showed a higher tensile strength and higher relative dielectric permittivity then the sample doped with Cr2O3. 
The main conclusion of this investigation is that the mechanical activation has the dominant influence on lowering the characteristic temperatures of all detected phase transitions and sintering processes. Using a mixture of several crystalline phases of alumina as a starting powder alleviates the incorporation of transition-metal cations into the alumina crystal lattice, leading to changes in microstructures of the prepared ceramics. Finally, changes in the microstructure and lattice disordering have the dominant influence on the final mechanical properties.",
publisher = "Societa ceramica italiana, Politecnico di Torino",
journal = "Abstract Book / XVI Conference and Exhibition of the European Ceramic Society XVI ECerS Conference, Torino, 16-20 June 2019",
title = "Electrical and mechanical properties of alumina doped with transition metal oxides sintered at 1400°C",
pages = "682-682"
}

The effect of ball milling on properties of sintered manganese-doped alumina

Filipović, Suzana; Obradović, Nina; Marković, Smilja; Mitrić, Miodrag; Balać, Igor; Đorđević, Antonije; Pavlović, Vladimir B.

(Elsevier, 2019)

TY  - JOUR
AU  - Filipović, Suzana
AU  - Obradović, Nina
AU  - Marković, Smilja
AU  - Mitrić, Miodrag
AU  - Balać, Igor
AU  - Đorđević, Antonije
AU  - Pavlović, Vladimir B.
PY  - 2019
UR  - http://www.sciencedirect.com/science/article/pii/S0921883119302596
UR  - http://dais.sanu.ac.rs/123456789/7027
AB  - Alumina-based compounds have many technological applications and attract great attention even after decades of investigation, due to their good chemical, electrical, and mechanical properties. A mixture of several alumina modifications (α-, κ-, γ-Al2O3) doped with 1 wt% of Mn2O3 was used for this experiment. The powder was mechanically activated for 60 min in an ethanol medium. After compaction, green bodies were sintered in the temperature range from 1200 to 1400 °C. Microstructures of the obtained specimens were investigated by scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS). The influence of morphological changes on electrical and mechanical properties was examined in detail. We have developed a test fixture and corresponding software for measurement of the relative dielectric permittivity and the loss tangent of ceramic specimens. This new method overcomes the problems of dimensions and shape of samples, as well as the problem of applying silver paste. The accuracy is around 2% for ε'r and 0.003 for tanδ. We demonstrate that the mechanical activation (MA) has the dominant influence on lowering the characteristic temperatures and microstructure development, which further leads to increased permittivity and tensile strength.
PB  - Elsevier
T2  - Advanced Powder Technology
T1  - The effect of ball milling on properties of sintered manganese-doped alumina
SP  - 2533
EP  - 2540
VL  - 30
IS  - 11
DO  - 10.1016/j.apt.2019.07.033
ER  - 
@article{
author = "Filipović, Suzana and Obradović, Nina and Marković, Smilja and Mitrić, Miodrag and Balać, Igor and Đorđević, Antonije and Pavlović, Vladimir B.",
year = "2019",
url = "http://www.sciencedirect.com/science/article/pii/S0921883119302596, http://dais.sanu.ac.rs/123456789/7027",
abstract = "Alumina-based compounds have many technological applications and attract great attention even after decades of investigation, due to their good chemical, electrical, and mechanical properties. A mixture of several alumina modifications (α-, κ-, γ-Al2O3) doped with 1 wt% of Mn2O3 was used for this experiment. The powder was mechanically activated for 60 min in an ethanol medium. After compaction, green bodies were sintered in the temperature range from 1200 to 1400 °C. Microstructures of the obtained specimens were investigated by scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS). The influence of morphological changes on electrical and mechanical properties was examined in detail. We have developed a test fixture and corresponding software for measurement of the relative dielectric permittivity and the loss tangent of ceramic specimens. This new method overcomes the problems of dimensions and shape of samples, as well as the problem of applying silver paste. The accuracy is around 2% for ε'r and 0.003 for tanδ. We demonstrate that the mechanical activation (MA) has the dominant influence on lowering the characteristic temperatures and microstructure development, which further leads to increased permittivity and tensile strength.",
publisher = "Elsevier",
journal = "Advanced Powder Technology",
title = "The effect of ball milling on properties of sintered manganese-doped alumina",
pages = "2533-2540",
volume = "30",
number = "11",
doi = "10.1016/j.apt.2019.07.033"
}
2
1

Kinetics of thermally activated processes in cordierite-based ceramics

Obradović, Nina; Blagojević, Vladimir A.; Filipović, Suzana; Đorđević, Nataša; Kosanović, Darko; Marković, Smilja; Kachlik, Martin; Maca, Karel; Pavlović, Vladimir B.

(Springer, 2019)

TY  - JOUR
AU  - Obradović, Nina
AU  - Blagojević, Vladimir A.
AU  - Filipović, Suzana
AU  - Đorđević, Nataša
AU  - Kosanović, Darko
AU  - Marković, Smilja
AU  - Kachlik, Martin
AU  - Maca, Karel
AU  - Pavlović, Vladimir B.
PY  - 2019
UR  - http://dais.sanu.ac.rs/123456789/7048
AB  - Thermally activated processes in cordierite-based ceramics were investigated to determine the effect of the mechanical activation and the addition of TeO2 on kinetic and thermodynamic parameters of these processes. Using a combination of dilatometry and DTA measurements in the 100–1400 °C temperature range, it was established that both the mechanical activation and the addition of TeO2 have a significant effect on processes in cordierite-based ceramics. A combination of 5 mass% addition of TeO2 and mechanical activation for 40 min reduced the sintering temperature of cordierite ceramics to around 1100 °C. In addition, the analysis of DTA measurements of mechanically activated samples indicates that the mechanical activation leads to intensification of the cordierite formation through an increase in concentration of surface defects and an increase in grain contact surface in the initial powder.
PB  - Springer
T2  - Journal of Thermal Analysis and Calorimetry
T1  - Kinetics of thermally activated processes in cordierite-based ceramics
SP  - 2989
EP  - 2998
VL  - 138
DO  - 10.1007/s10973-018-7924-1
ER  - 
@article{
author = "Obradović, Nina and Blagojević, Vladimir A. and Filipović, Suzana and Đorđević, Nataša and Kosanović, Darko and Marković, Smilja and Kachlik, Martin and Maca, Karel and Pavlović, Vladimir B.",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/7048",
abstract = "Thermally activated processes in cordierite-based ceramics were investigated to determine the effect of the mechanical activation and the addition of TeO2 on kinetic and thermodynamic parameters of these processes. Using a combination of dilatometry and DTA measurements in the 100–1400 °C temperature range, it was established that both the mechanical activation and the addition of TeO2 have a significant effect on processes in cordierite-based ceramics. A combination of 5 mass% addition of TeO2 and mechanical activation for 40 min reduced the sintering temperature of cordierite ceramics to around 1100 °C. In addition, the analysis of DTA measurements of mechanically activated samples indicates that the mechanical activation leads to intensification of the cordierite formation through an increase in concentration of surface defects and an increase in grain contact surface in the initial powder.",
publisher = "Springer",
journal = "Journal of Thermal Analysis and Calorimetry",
title = "Kinetics of thermally activated processes in cordierite-based ceramics",
pages = "2989-2998",
volume = "138",
doi = "10.1007/s10973-018-7924-1"
}
1
1
1

Controllable synthesis of Fe3O4-wollastonite adsorbents for efficient heavy metal ions/oxyanions removal

Rusmirović, Jelena; Obradović, Nina; Perendija, Jovana; Umićević, Ana; Kapidžić, Ana; Vlahović, Branislav; Pavlović, Vera P.; Marinković, Aleksandar D.; Pavlović, Vladimir B.

(Springer, 2019)

TY  - JOUR
AU  - Rusmirović, Jelena
AU  - Obradović, Nina
AU  - Perendija, Jovana
AU  - Umićević, Ana
AU  - Kapidžić, Ana
AU  - Vlahović, Branislav
AU  - Pavlović, Vera P.
AU  - Marinković, Aleksandar D.
AU  - Pavlović, Vladimir B.
PY  - 2019
UR  - http://dais.sanu.ac.rs/123456789/5764
AB  - Iron oxide, in the form of magnetite (MG)–functionalized porous wollastonite (WL), was used as an adsorbent for heavy metal ions (cadmium and nickel) and oxyanions (chromate and phosphate) removal from water. The porous WL was synthesized from calcium carbonate and siloxane by controlled sintering process using low molecular weight submicrosized poly(methyl methacrylate) as a pore-forming agent. The precipitation of MG nanoparticles was carried out directly by a polyol-medium solvothermal method or via branched amino/carboxylic acid cross-linker by solvent/nonsolvent method producing WL/MG and WL-γ-APS/MG adsorbents, respectively. The structure/properties of MG functionalized WL was confirmed by applying FTIR, Raman, XRD, Mössbauer, and SEM analysis. Higher adsorption capacities of 73.126, 66.144, 64.168, and 63.456 mg g−1 for WL-γ-APS/MG in relation to WL/MG of 55.450, 52.019, 48.132, and 47.382 mg g−1 for Cd2+, Ni2+, phosphate, and chromate, respectively, were obtained using nonlinear Langmuir model fitting. Adsorption phenomena were analyzed using monolayer statistical physics model for single adsorption with one energy. Kinetic study showed exceptionally higher pseudo-second-order rate constants for WL-γ-APS/MG, e.g., 1.17–13.4 times, with respect to WL/MG indicating importance of both WL surface modification and controllable precipitation of MG on WL-γ-APS.
PB  - Springer
T2  - Environmental Science and Pollution Research
T1  - Controllable synthesis of Fe3O4-wollastonite adsorbents for efficient heavy metal ions/oxyanions removal
SP  - 12379
EP  - 12398
VL  - 26
IS  - 12
DO  - 10.1007/s11356-019-04625-0
ER  - 
@article{
author = "Rusmirović, Jelena and Obradović, Nina and Perendija, Jovana and Umićević, Ana and Kapidžić, Ana and Vlahović, Branislav and Pavlović, Vera P. and Marinković, Aleksandar D. and Pavlović, Vladimir B.",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/5764",
abstract = "Iron oxide, in the form of magnetite (MG)–functionalized porous wollastonite (WL), was used as an adsorbent for heavy metal ions (cadmium and nickel) and oxyanions (chromate and phosphate) removal from water. The porous WL was synthesized from calcium carbonate and siloxane by controlled sintering process using low molecular weight submicrosized poly(methyl methacrylate) as a pore-forming agent. The precipitation of MG nanoparticles was carried out directly by a polyol-medium solvothermal method or via branched amino/carboxylic acid cross-linker by solvent/nonsolvent method producing WL/MG and WL-γ-APS/MG adsorbents, respectively. The structure/properties of MG functionalized WL was confirmed by applying FTIR, Raman, XRD, Mössbauer, and SEM analysis. Higher adsorption capacities of 73.126, 66.144, 64.168, and 63.456 mg g−1 for WL-γ-APS/MG in relation to WL/MG of 55.450, 52.019, 48.132, and 47.382 mg g−1 for Cd2+, Ni2+, phosphate, and chromate, respectively, were obtained using nonlinear Langmuir model fitting. Adsorption phenomena were analyzed using monolayer statistical physics model for single adsorption with one energy. Kinetic study showed exceptionally higher pseudo-second-order rate constants for WL-γ-APS/MG, e.g., 1.17–13.4 times, with respect to WL/MG indicating importance of both WL surface modification and controllable precipitation of MG on WL-γ-APS.",
publisher = "Springer",
journal = "Environmental Science and Pollution Research",
title = "Controllable synthesis of Fe3O4-wollastonite adsorbents for efficient heavy metal ions/oxyanions removal",
pages = "12379-12398",
volume = "26",
number = "12",
doi = "10.1007/s11356-019-04625-0"
}
1
3
4
3

Characterization of MgAl2O4 sintered ceramics

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

(ETRAN, 2019)

TY  - JOUR
AU  - Obradović, Nina
AU  - Fahrenholtz, William G.
AU  - Filipović, Suzana
AU  - Corlett, Cole
AU  - Đorđević, Pavle
AU  - Rogan, Jelena
AU  - Vulić, Predrag J.
AU  - Buljak, Vladimir
AU  - Pavlović, Vladimir B.
PY  - 2019
UR  - http://dais.sanu.ac.rs/123456789/6949
AB  - Single phase MgAl2O4 was made from a one-to-one molar ratio of MgO and Al2O3 powders mixed using ball-milling. Mixtures of MgO and Al2O3 were subsequently treated in planetary ball mill for 30, 60, 90 and 120 minutes in air. The aim of this study was to examine phase composition, microstructure, and densification behavior of sintered specimens. After sintering in dilatometer at 1500 °C, the powder was converted to single phase MgAl2O4. The results show that mechanical activation improved the densification behavior of MgAl2O4 sintered specimens, and it reduced the onset temperature for sintering by approx. 100 oC. Based on dilatometer data, powders were subsequently densified at 1450 oC by hot pressing. Almost аll specimens exhibited full density, while sample activated for 30 minutes showed the fastest densification rate.
PB  - ETRAN
T2  - Science of Sintering
T1  - Characterization of MgAl2O4 sintered ceramics
SP  - 363
EP  - 376
VL  - 51
IS  - 4
DO  - 10.2298/SOS1904363O
ER  - 
@article{
author = "Obradović, Nina and Fahrenholtz, William G. and Filipović, Suzana and Corlett, Cole and Đorđević, Pavle and Rogan, Jelena and Vulić, Predrag J. and Buljak, Vladimir and Pavlović, Vladimir B.",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/6949",
abstract = "Single phase MgAl2O4 was made from a one-to-one molar ratio of MgO and Al2O3 powders mixed using ball-milling. Mixtures of MgO and Al2O3 were subsequently treated in planetary ball mill for 30, 60, 90 and 120 minutes in air. The aim of this study was to examine phase composition, microstructure, and densification behavior of sintered specimens. After sintering in dilatometer at 1500 °C, the powder was converted to single phase MgAl2O4. The results show that mechanical activation improved the densification behavior of MgAl2O4 sintered specimens, and it reduced the onset temperature for sintering by approx. 100 oC. Based on dilatometer data, powders were subsequently densified at 1450 oC by hot pressing. Almost аll specimens exhibited full density, while sample activated for 30 minutes showed the fastest densification rate.",
publisher = "ETRAN",
journal = "Science of Sintering",
title = "Characterization of MgAl2O4 sintered ceramics",
pages = "363-376",
volume = "51",
number = "4",
doi = "10.2298/SOS1904363O"
}
1
1

Controllable synthesis of Fe3O4-wollastonite adsorbents for efficient heavy metal ions/oxyanions removal

Rusmirović, Jelena; Obradović, Nina; Perendija, Jovana; Umićević, Ana; Kapidžić, Ana; Vlahović, Branislav; Pavlović, Vera; Marinković, Aleksandar D.; Pavlović, Vladimir B.

(Springer, 2019)

TY  - JOUR
AU  - Rusmirović, Jelena
AU  - Obradović, Nina
AU  - Perendija, Jovana
AU  - Umićević, Ana
AU  - Kapidžić, Ana
AU  - Vlahović, Branislav
AU  - Pavlović, Vera
AU  - Marinković, Aleksandar D.
AU  - Pavlović, Vladimir B.
PY  - 2019
UR  - https://doi.org/10.1007/s11356-019-04625-0
UR  - http://dais.sanu.ac.rs/123456789/5273
AB  - Iron oxide, in the form of magnetite (MG)–functionalized porous wollastonite (WL), was used as an adsorbent for heavy metal ions (cadmium and nickel) and oxyanions (chromate and phosphate) removal from water. The porous WL was synthesized from calcium carbonate and siloxane by controlled sintering process using low molecular weight submicrosized poly(methyl methacrylate) as a pore-forming agent. The precipitation of MG nanoparticles was carried out directly by a polyol-medium solvothermal method or via branched amino/carboxylic acid cross-linker by solvent/nonsolvent method producing WL/MG and WL-γ-APS/MG adsorbents, respectively. The structure/properties of MG functionalized WL was confirmed by applying FTIR, Raman, XRD, Mössbauer, and SEM analysis. Higher adsorption capacities of 73.126, 66.144, 64.168, and 63.456 mg g−1 for WL-γ-APS/MG in relation to WL/MG of 55.450, 52.019, 48.132, and 47.382 mg g−1 for Cd2+, Ni2+, phosphate, and chromate, respectively, were obtained using nonlinear Langmuir model fitting. Adsorption phenomena were analyzed using monolayer statistical physics model for single adsorption with one energy. Kinetic study showed exceptionally higher pseudo-second-order rate constants for WL-γ-APS/MG, e.g., 1.17–13.4 times, with respect to WL/MG indicating importance of both WL surface modification and controllable precipitation of MG on WL-γ-APS.
PB  - Springer
T2  - Environmental Science and Pollution Research
T1  - Controllable synthesis of Fe3O4-wollastonite adsorbents for efficient heavy metal ions/oxyanions removal
SP  - 12379
EP  - 12398
VL  - 26
IS  - 12
DO  - 10.1007/s11356-019-04625-0
ER  - 
@article{
author = "Rusmirović, Jelena and Obradović, Nina and Perendija, Jovana and Umićević, Ana and Kapidžić, Ana and Vlahović, Branislav and Pavlović, Vera and Marinković, Aleksandar D. and Pavlović, Vladimir B.",
year = "2019",
url = "https://doi.org/10.1007/s11356-019-04625-0, http://dais.sanu.ac.rs/123456789/5273",
abstract = "Iron oxide, in the form of magnetite (MG)–functionalized porous wollastonite (WL), was used as an adsorbent for heavy metal ions (cadmium and nickel) and oxyanions (chromate and phosphate) removal from water. The porous WL was synthesized from calcium carbonate and siloxane by controlled sintering process using low molecular weight submicrosized poly(methyl methacrylate) as a pore-forming agent. The precipitation of MG nanoparticles was carried out directly by a polyol-medium solvothermal method or via branched amino/carboxylic acid cross-linker by solvent/nonsolvent method producing WL/MG and WL-γ-APS/MG adsorbents, respectively. The structure/properties of MG functionalized WL was confirmed by applying FTIR, Raman, XRD, Mössbauer, and SEM analysis. Higher adsorption capacities of 73.126, 66.144, 64.168, and 63.456 mg g−1 for WL-γ-APS/MG in relation to WL/MG of 55.450, 52.019, 48.132, and 47.382 mg g−1 for Cd2+, Ni2+, phosphate, and chromate, respectively, were obtained using nonlinear Langmuir model fitting. Adsorption phenomena were analyzed using monolayer statistical physics model for single adsorption with one energy. Kinetic study showed exceptionally higher pseudo-second-order rate constants for WL-γ-APS/MG, e.g., 1.17–13.4 times, with respect to WL/MG indicating importance of both WL surface modification and controllable precipitation of MG on WL-γ-APS.",
publisher = "Springer",
journal = "Environmental Science and Pollution Research",
title = "Controllable synthesis of Fe3O4-wollastonite adsorbents for efficient heavy metal ions/oxyanions removal",
pages = "12379-12398",
volume = "26",
number = "12",
doi = "10.1007/s11356-019-04625-0"
}
1
3
4
3

Effect of Mechanical Activation on the Densification Behavior of MgAl2O4 Spinel

Obradović, Nina; Fahrenholtz, William G.; Filipović, Suzana; Đorđević, Pavle; Rogan, Jelena; Pavlović, Vladimir B.

(The Ceramic Society of Japan, 2019)

TY  - CONF
AU  - Obradović, Nina
AU  - Fahrenholtz, William G.
AU  - Filipović, Suzana
AU  - Đorđević, Pavle
AU  - Rogan, Jelena
AU  - Pavlović, Vladimir B.
PY  - 2019
UR  - http://dais.sanu.ac.rs/123456789/7050
AB  - Magnesium aluminate and other alumina-based spinels attract attention due to their high hardness, high mechanical strength, and low dielectric constant. MgAl2O4 was produced by solid-state reaction between MgO and a-Al2O3 powders. Mechanical activation was used to increase the reactivity of powders and decrease the sintering temperatures. Mechanical activation of mixed powders was performed in a high-energy planetary ball mill in air for 30, 60, 90, and 120 minutes. The resulting powders were characterized to determine the effect of activation on surface area, particle size, and crystallinity. Mechanical activation decreased particle size, increased surface area, and increased the width of peaks in x-ray diffraction. Dilatometry was used to monitor densification behavior up to 1500 °C. For non-activated powders, sintering started at approximately 1400 °C, while for activated powders, the onset temperature decreased to about 1340 °C. Mechanical activation is an efficient method to improve the densification behaviour of MgAl2O4 produced from mixed oxide powders.
PB  - The Ceramic Society of Japan
C3  - The 13th Pacific Rim Conference of Ceramic Societies (PACRIM13), October 27 - November 1, 2019, Okinawa Convention Center, Japan
T1  - Effect of Mechanical Activation on the Densification Behavior of MgAl2O4 Spinel
SP  - 30-B1C-S13-14
ER  - 
@conference{
author = "Obradović, Nina and Fahrenholtz, William G. and Filipović, Suzana and Đorđević, Pavle and Rogan, Jelena and Pavlović, Vladimir B.",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/7050",
abstract = "Magnesium aluminate and other alumina-based spinels attract attention due to their high hardness, high mechanical strength, and low dielectric constant. MgAl2O4 was produced by solid-state reaction between MgO and a-Al2O3 powders. Mechanical activation was used to increase the reactivity of powders and decrease the sintering temperatures. Mechanical activation of mixed powders was performed in a high-energy planetary ball mill in air for 30, 60, 90, and 120 minutes. The resulting powders were characterized to determine the effect of activation on surface area, particle size, and crystallinity. Mechanical activation decreased particle size, increased surface area, and increased the width of peaks in x-ray diffraction. Dilatometry was used to monitor densification behavior up to 1500 °C. For non-activated powders, sintering started at approximately 1400 °C, while for activated powders, the onset temperature decreased to about 1340 °C. Mechanical activation is an efficient method to improve the densification behaviour of MgAl2O4 produced from mixed oxide powders.",
publisher = "The Ceramic Society of Japan",
journal = "The 13th Pacific Rim Conference of Ceramic Societies (PACRIM13), October 27 - November 1, 2019, Okinawa Convention Center, Japan",
title = "Effect of Mechanical Activation on the Densification Behavior of MgAl2O4 Spinel",
pages = "30-B1C-S13-14"
}

Three-Axis’ Heat Loss Anemometer Comprising Thick-Film Segmented Thermistors

Aleksić, Stanko O.; Mitrović, Nebojša S.; Nikolić, Zoran; Luković, Miloljub D.; Obradović, Nina; Luković, Snežana G.

(IEEE, 2019)

TY  - JOUR
AU  - Aleksić, Stanko O.
AU  - Mitrović, Nebojša S.
AU  - Nikolić, Zoran
AU  - Luković, Miloljub D.
AU  - Obradović, Nina
AU  - Luković, Snežana G.
PY  - 2019
UR  - http://dais.sanu.ac.rs/123456789/7037
AB  - NTC thick-film segmented thermistors were used as anemometer sensing devices. They were screen printed of thick-film thermistor paste based on modified NiMn2O4 fine powder, organic vehicle, and glass frit. Their electrical properties, such as resistance vs. temperature R(T) and thermistor exponential factor B were obtained using measurements in the climatic test chamber. A uniaxial anemometer was formed using a thick-film segmented thermistor, which was placed in the hole drilled in rectangular piece of thermally insulating material. The uniaxial anemometer was used for the optimization of operating point of segmented thermistors as self-heating/wind sensing devices. The dc supply voltage was correlated with the air temperature sub-ranges (RCV). The power save mode such as 30s self-heating/5 min pause was used to measure the thermistor response on stable wind blow. The three-axis' anemometer was formed using five sensor devices placed in five holes drilled in the cubical piece of thermally insulating material: three thermistor sensors measure wind speed on the x, y, z - axes, the fourth sensor Pt 1000 measures the air temperature T, while the fifth sensor (capacitive type) measures humidity H. The obtained sensitivity and inaccuracy were compared with respective ones of other anemometers.
PB  - IEEE
T2  - IEEE Sensors Journal
T1  - Three-Axis’ Heat Loss Anemometer Comprising Thick-Film Segmented Thermistors
SP  - 10228
EP  - 10235
VL  - 19
IS  - 22
DO  - 10.1109/JSEN.2019.2929356
ER  - 
@article{
author = "Aleksić, Stanko O. and Mitrović, Nebojša S. and Nikolić, Zoran and Luković, Miloljub D. and Obradović, Nina and Luković, Snežana G.",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/7037",
abstract = "NTC thick-film segmented thermistors were used as anemometer sensing devices. They were screen printed of thick-film thermistor paste based on modified NiMn2O4 fine powder, organic vehicle, and glass frit. Their electrical properties, such as resistance vs. temperature R(T) and thermistor exponential factor B were obtained using measurements in the climatic test chamber. A uniaxial anemometer was formed using a thick-film segmented thermistor, which was placed in the hole drilled in rectangular piece of thermally insulating material. The uniaxial anemometer was used for the optimization of operating point of segmented thermistors as self-heating/wind sensing devices. The dc supply voltage was correlated with the air temperature sub-ranges (RCV). The power save mode such as 30s self-heating/5 min pause was used to measure the thermistor response on stable wind blow. The three-axis' anemometer was formed using five sensor devices placed in five holes drilled in the cubical piece of thermally insulating material: three thermistor sensors measure wind speed on the x, y, z - axes, the fourth sensor Pt 1000 measures the air temperature T, while the fifth sensor (capacitive type) measures humidity H. The obtained sensitivity and inaccuracy were compared with respective ones of other anemometers.",
publisher = "IEEE",
journal = "IEEE Sensors Journal",
title = "Three-Axis’ Heat Loss Anemometer Comprising Thick-Film Segmented Thermistors",
pages = "10228-10235",
volume = "19",
number = "22",
doi = "10.1109/JSEN.2019.2929356"
}

The effect of mechanical activation on synthesis and properties of MgAl2O4 ceramics

Obradović, Nina; Fahrenholtz, William G.; Filipović, Suzana; Kosanović, Darko; Dapčević, Aleksandra; Rogan, Jelena; Pavlović, Vladimir B.

(Societa ceramica italiana, 2019)

TY  - CONF
AU  - Obradović, Nina
AU  - Fahrenholtz, William G.
AU  - Filipović, Suzana
AU  - Kosanović, Darko
AU  - Dapčević, Aleksandra
AU  - Rogan, Jelena
AU  - Pavlović, Vladimir B.
PY  - 2019
UR  - http://dais.sanu.ac.rs/123456789/7022
AB  - Magnesium aluminate, MgAl2O4, and other alumina-based spinels are refractory ceramics with high hardness and resistance to chemical attack while also being possible microwave dielectrics. Pure MgAl2O4 can be optically transparent when fully dense. Spinels exhibit inversion, which results in disorder among occupancy of A and B site cations. The goal of this study was to examine the effects of mechanical activation and composition on the temperature required for spinel formation and the site occupancy in the resulting spinel. 
MgAl2O4 was produced by solid state reaction between MgO and alpha-Al2O3. The starting powders were mixed by ball milling to homogenize the powders without significant particle size reduction. Mechanical activation of mixed powders was performed in a high-energy planetary ball mill in air for 1 h. Powders were compacted at 300 MPa. Heat treatments were performed in air, at temperatures ranging from 1200 to 1500 °C with 2 h dwell time, to determine the amount of spinel formation as a function of temperature. Phase composition and microstructure of initial powders and heated samples were determined by means of X-ray diffraction, particle size analysis, and scanning electron microscopy. The influence of milling and consolidation parameters were studied by electrical measurements and mechanical characterization. 
The main results of this study were that mechanical activation for 60 minutes initiated a mechano-chemical reaction, and resulted in spinel formation at much lower temperatures than within non-activated powders. Microstructures of ceramics sintered below 1400 oC indicated that final stage sintering started at much lower temperatures for activated samples than for non-activated samples. 
Changes in microstructure parameters, as a consequence of mechanical treatment and subsequent heating of investigated powder mixtures, strongly affect electrical and mechanical properties of the final ceramics.
PB  - Societa ceramica italiana
PB  - Politecnico di Torino
C3  - Abstract Book / XVI Conference and Exhibition of the European Ceramic Society XVI ECerS Conference, Torino, 16-20 June 2019
T1  - The effect of mechanical activation on synthesis and properties of MgAl2O4 ceramics
SP  - 262
EP  - 262
ER  - 
@conference{
author = "Obradović, Nina and Fahrenholtz, William G. and Filipović, Suzana and Kosanović, Darko and Dapčević, Aleksandra and Rogan, Jelena and Pavlović, Vladimir B.",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/7022",
abstract = "Magnesium aluminate, MgAl2O4, and other alumina-based spinels are refractory ceramics with high hardness and resistance to chemical attack while also being possible microwave dielectrics. Pure MgAl2O4 can be optically transparent when fully dense. Spinels exhibit inversion, which results in disorder among occupancy of A and B site cations. The goal of this study was to examine the effects of mechanical activation and composition on the temperature required for spinel formation and the site occupancy in the resulting spinel. 
MgAl2O4 was produced by solid state reaction between MgO and alpha-Al2O3. The starting powders were mixed by ball milling to homogenize the powders without significant particle size reduction. Mechanical activation of mixed powders was performed in a high-energy planetary ball mill in air for 1 h. Powders were compacted at 300 MPa. Heat treatments were performed in air, at temperatures ranging from 1200 to 1500 °C with 2 h dwell time, to determine the amount of spinel formation as a function of temperature. Phase composition and microstructure of initial powders and heated samples were determined by means of X-ray diffraction, particle size analysis, and scanning electron microscopy. The influence of milling and consolidation parameters were studied by electrical measurements and mechanical characterization. 
The main results of this study were that mechanical activation for 60 minutes initiated a mechano-chemical reaction, and resulted in spinel formation at much lower temperatures than within non-activated powders. Microstructures of ceramics sintered below 1400 oC indicated that final stage sintering started at much lower temperatures for activated samples than for non-activated samples. 
Changes in microstructure parameters, as a consequence of mechanical treatment and subsequent heating of investigated powder mixtures, strongly affect electrical and mechanical properties of the final ceramics.",
publisher = "Societa ceramica italiana, Politecnico di Torino",
journal = "Abstract Book / XVI Conference and Exhibition of the European Ceramic Society XVI ECerS Conference, Torino, 16-20 June 2019",
title = "The effect of mechanical activation on synthesis and properties of MgAl2O4 ceramics",
pages = "262-262"
}

Influence of Mechanical Activation on Electrical Properties of Ceramic Materials in VHF Band

Obradović, Nina; Đorđević, Antonije

(Belgrade : ETRAN, 2019)

TY  - CONF
AU  - Obradović, Nina
AU  - Đorđević, Antonije
PY  - 2019
UR  - http://dais.sanu.ac.rs/123456789/6962
AB  - Mechanical activation is commonly used as a pre-sintering process in order to enhance the reactivity of materials, reduce the particle size, increase diffusion rates, accelerate the reaction, and lower the sintering temperature. The mechanical activation can affect the final electrical and mechanical characteristics. In this paper we consider the influence of the mechanical activation on the permittivity and the loss tangent. We outline methods for evaluation of these parameters, with emphasis on our coaxial-chamber technique for measurements in the VHF band.
PB  - Belgrade : ETRAN
PB  - Belgrade : Academic Mind
C3  - Proceedings of Papers – 6th International Conference on Electrical, Electronic and Computing Engineering, IcETRAN 2019, Silver Lake, Serbia, June 03 – 06, 2019 / Zbornik radova - 63. Konferencija za elektroniku, telekomunikacije, računarstvo, automatiku i nuklearnu tehniku, Srebrno jezero, 03 – 06. juna, 2019. godine
T1  - Influence of Mechanical Activation on Electrical Properties of Ceramic Materials in VHF Band
SP  - 636
EP  - 645
ER  - 
@conference{
author = "Obradović, Nina and Đorđević, Antonije",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/6962",
abstract = "Mechanical activation is commonly used as a pre-sintering process in order to enhance the reactivity of materials, reduce the particle size, increase diffusion rates, accelerate the reaction, and lower the sintering temperature. The mechanical activation can affect the final electrical and mechanical characteristics. In this paper we consider the influence of the mechanical activation on the permittivity and the loss tangent. We outline methods for evaluation of these parameters, with emphasis on our coaxial-chamber technique for measurements in the VHF band.",
publisher = "Belgrade : ETRAN, Belgrade : Academic Mind",
journal = "Proceedings of Papers – 6th International Conference on Electrical, Electronic and Computing Engineering, IcETRAN 2019, Silver Lake, Serbia, June 03 – 06, 2019 / Zbornik radova - 63. Konferencija za elektroniku, telekomunikacije, računarstvo, automatiku i nuklearnu tehniku, Srebrno jezero, 03 – 06. juna, 2019. godine",
title = "Influence of Mechanical Activation on Electrical Properties of Ceramic Materials in VHF Band",
pages = "636-645"
}

Application of magnetite/3D-printed wollastonite hybrid sorbent for As(V) removal from water

Trajković, Isaak; Obradović, Nina; Marinković, Aleksandar; Casas Luna, Mariano; Pavlović, Vladimir B.

(Belgrade : Serbian Ceramic Society, 2019)

TY  - CONF
AU  - Trajković, Isaak
AU  - Obradović, Nina
AU  - Marinković, Aleksandar
AU  - Casas Luna, Mariano
AU  - Pavlović, Vladimir B.
PY  - 2019
UR  - http://dais.sanu.ac.rs/123456789/6920
AB  - The maximal allowed concentration (MAC) for As(V) in water decreased from 50 to 10 μg/l, by considering the harmful effects of arsenic on the environment and human health. In order to achieve the established rigorous requirements, it is necessary to develop new materials and design new forms of adsorbents that can reduce the concentration of arsenic in drinking water. In this paper, the synthesized magnetite/3D-printed wollastonite hybrid sorbent was used to remove As(V) from aqueous solutions. 3D-printed wollastonite was obtained using the 3D-printing technique from methylhydrocyclosiloxane and calcium carbonate as precursors. Synthesis of adsorption material was carried out by depositing magnetite from an iron(II)-sulfate solution by potassium hydroxide on 3D-printed wollastonite. The adsorption properties of the hybrid adsorbent depend on the properties of magnetite and its porosity. This could be achieved by modifying the processes of depositing magnetite on the porous 3D-printed wollastonite. Characterization of the obtained material was performed using FTIR, SEM and TG-DTA. An investigation of the sorption properties of hybrid adsorbents was carried out for As(V) removal - one relative to the starting pH value of the solution, the adsorbent mass, the temperature and the adsorption time. Determination of adsorption parameters was performed by applying Langmuir, Freundlich and Dubinin- Radushkevich equations. Kinetics, using pseudo-first, pseudo-second and second order equations, as well as diffusion rate were determined using Veber-Moris and HSDM models. Determination of kinetics and adhesion parameters at three different temperatures enabled the calculation of thermodynamic and activation parameters of the adsorption process, which contributed to a better understanding of the adsorption mechanism.
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  - Application of magnetite/3D-printed wollastonite hybrid sorbent for As(V) removal from water
SP  - 52
EP  - 52
ER  - 
@conference{
author = "Trajković, Isaak and Obradović, Nina and Marinković, Aleksandar and Casas Luna, Mariano and Pavlović, Vladimir B.",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/6920",
abstract = "The maximal allowed concentration (MAC) for As(V) in water decreased from 50 to 10 μg/l, by considering the harmful effects of arsenic on the environment and human health. In order to achieve the established rigorous requirements, it is necessary to develop new materials and design new forms of adsorbents that can reduce the concentration of arsenic in drinking water. In this paper, the synthesized magnetite/3D-printed wollastonite hybrid sorbent was used to remove As(V) from aqueous solutions. 3D-printed wollastonite was obtained using the 3D-printing technique from methylhydrocyclosiloxane and calcium carbonate as precursors. Synthesis of adsorption material was carried out by depositing magnetite from an iron(II)-sulfate solution by potassium hydroxide on 3D-printed wollastonite. The adsorption properties of the hybrid adsorbent depend on the properties of magnetite and its porosity. This could be achieved by modifying the processes of depositing magnetite on the porous 3D-printed wollastonite. Characterization of the obtained material was performed using FTIR, SEM and TG-DTA. An investigation of the sorption properties of hybrid adsorbents was carried out for As(V) removal - one relative to the starting pH value of the solution, the adsorbent mass, the temperature and the adsorption time. Determination of adsorption parameters was performed by applying Langmuir, Freundlich and Dubinin- Radushkevich equations. Kinetics, using pseudo-first, pseudo-second and second order equations, as well as diffusion rate were determined using Veber-Moris and HSDM models. Determination of kinetics and adhesion parameters at three different temperatures enabled the calculation of thermodynamic and activation parameters of the adsorption process, which contributed to a better understanding of the adsorption mechanism.",
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 = "Application of magnetite/3D-printed wollastonite hybrid sorbent for As(V) removal from water",
pages = "52-52"
}

Three-Axis’ Heat Loss Anemometer Comprising Thick-Film Segmented Thermistors

Aleksić, Stanko O.; Mitrović, Nebojša S.; Nikolić, Zoran; Luković, Miloljub D.; Obradović, Nina; Luković, Snežana G.

(IEEE, 2019)

TY  - JOUR
AU  - Aleksić, Stanko O.
AU  - Mitrović, Nebojša S.
AU  - Nikolić, Zoran
AU  - Luković, Miloljub D.
AU  - Obradović, Nina
AU  - Luković, Snežana G.
PY  - 2019
UR  - http://dais.sanu.ac.rs/123456789/6907
AB  - NTC thick-film segmented thermistors were used as anemometer sensing devices. They were screen printed of thick-film thermistor paste based on modified NiMn2O4 fine powder, organic vehicle, and glass frit. Their electrical properties, such as resistance vs. temperature R(T) and thermistor exponential factor B were obtained using measurements in the climatic test chamber. A uniaxial anemometer was formed using a thick-film segmented thermistor, which was placed in the hole drilled in rectangular piece of thermally insulating material. The uniaxial anemometer was used for the optimization of operating point of segmented thermistors as self-heating/wind sensing devices. The dc supply voltage was correlated with the air temperature sub-ranges (RCV). The power save mode such as 30s self-heating/5 min pause was used to measure the thermistor response on stable wind blow. The three-axis' anemometer was formed using five sensor devices placed in five holes drilled in the cubical piece of thermally insulating material: three thermistor sensors measure wind speed on the x, y, z - axes, the fourth sensor Pt 1000 measures the air temperature T, while the fifth sensor (capacitive type) measures humidity H. The obtained sensitivity and inaccuracy were compared with respective ones of other anemometers.
PB  - IEEE
T2  - IEEE Sensors Journal
T1  - Three-Axis’ Heat Loss Anemometer Comprising Thick-Film Segmented Thermistors
SP  - 10228
EP  - 10235
VL  - 19
IS  - 22
DO  - 10.1109/JSEN.2019.2929356
ER  - 
@article{
author = "Aleksić, Stanko O. and Mitrović, Nebojša S. and Nikolić, Zoran and Luković, Miloljub D. and Obradović, Nina and Luković, Snežana G.",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/6907",
abstract = "NTC thick-film segmented thermistors were used as anemometer sensing devices. They were screen printed of thick-film thermistor paste based on modified NiMn2O4 fine powder, organic vehicle, and glass frit. Their electrical properties, such as resistance vs. temperature R(T) and thermistor exponential factor B were obtained using measurements in the climatic test chamber. A uniaxial anemometer was formed using a thick-film segmented thermistor, which was placed in the hole drilled in rectangular piece of thermally insulating material. The uniaxial anemometer was used for the optimization of operating point of segmented thermistors as self-heating/wind sensing devices. The dc supply voltage was correlated with the air temperature sub-ranges (RCV). The power save mode such as 30s self-heating/5 min pause was used to measure the thermistor response on stable wind blow. The three-axis' anemometer was formed using five sensor devices placed in five holes drilled in the cubical piece of thermally insulating material: three thermistor sensors measure wind speed on the x, y, z - axes, the fourth sensor Pt 1000 measures the air temperature T, while the fifth sensor (capacitive type) measures humidity H. The obtained sensitivity and inaccuracy were compared with respective ones of other anemometers.",
publisher = "IEEE",
journal = "IEEE Sensors Journal",
title = "Three-Axis’ Heat Loss Anemometer Comprising Thick-Film Segmented Thermistors",
pages = "10228-10235",
volume = "19",
number = "22",
doi = "10.1109/JSEN.2019.2929356"
}

Morphological and structural characterization of spinel MgAl2O4

Filipović, Suzana; Obradović, Nina; Fahrenholtz, William G.; Marinković, Bojan A.; Rogan, Jelena; Lević, S.; Pavlović, Vladimir B.

(Belgrade : Serbian Ceramic Society, 2019)

TY  - CONF
AU  - Filipović, Suzana
AU  - Obradović, Nina
AU  - Fahrenholtz, William G.
AU  - Marinković, Bojan A.
AU  - Rogan, Jelena
AU  - Lević, S.
AU  - Pavlović, Vladimir B.
PY  - 2019
UR  - http://dais.sanu.ac.rs/123456789/6779
AB  - Magnesium aluminate has spinel structure and very good mechanical, chemical, and thermal properties. Owing to these properties, it has a wide range of applications including refractory ceramics, optically transparent ceramic windows and armors. Its low dielectric permeability and low loss tangent enable its using for integrated electronic devices, as well. Furthermore, as a porous ceramic, magnesium aluminate has important application as humidity sensor, catalyst and filter for waste water purification. In this paper, synthesis and characterization of MgAl2O4 was performed. Stochiometric ratio of MgO and Al2O3powders was mixed and calcined within the temperatures range 1500-1800 oC to produce pure spinel phase. Thereafter pellets were crushed and treated in planetary ball mill for 60 minutes to obtained fine grain. All powders, calcined and milled, were examined for phase composition, crystal structure, and morphology. The obtained results showed that by increasing the temperature denser samples but more fragile have been synthesized. Milling for 1 hour leads to crumble of bigger particles and getting finer, single phase powders. XRPD and Raman spectroscopy showed disorder in crystal structure after milling.
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  - Morphological and structural characterization of spinel MgAl2O4
SP  - 32
EP  - 32
ER  - 
@conference{
author = "Filipović, Suzana and Obradović, Nina and Fahrenholtz, William G. and Marinković, Bojan A. and Rogan, Jelena and Lević, S. and Pavlović, Vladimir B.",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/6779",
abstract = "Magnesium aluminate has spinel structure and very good mechanical, chemical, and thermal properties. Owing to these properties, it has a wide range of applications including refractory ceramics, optically transparent ceramic windows and armors. Its low dielectric permeability and low loss tangent enable its using for integrated electronic devices, as well. Furthermore, as a porous ceramic, magnesium aluminate has important application as humidity sensor, catalyst and filter for waste water purification. In this paper, synthesis and characterization of MgAl2O4 was performed. Stochiometric ratio of MgO and Al2O3powders was mixed and calcined within the temperatures range 1500-1800 oC to produce pure spinel phase. Thereafter pellets were crushed and treated in planetary ball mill for 60 minutes to obtained fine grain. All powders, calcined and milled, were examined for phase composition, crystal structure, and morphology. The obtained results showed that by increasing the temperature denser samples but more fragile have been synthesized. Milling for 1 hour leads to crumble of bigger particles and getting finer, single phase powders. XRPD and Raman spectroscopy showed disorder in crystal structure after milling.",
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 = "Morphological and structural characterization of spinel MgAl2O4",
pages = "32-32"
}

Kinetics of thermally activated processes in cordierite-based ceramics

Obradović, Nina; Blagojević, Vladimir A.; Filipović, Suzana; Đorđević, Nataša; Kosanović, Darko; Marković, Smilja; Kachlik, Martin; Maca, Karel; Pavlović, Vladimir B.

(Springer, 2019)

TY  - JOUR
AU  - Obradović, Nina
AU  - Blagojević, Vladimir A.
AU  - Filipović, Suzana
AU  - Đorđević, Nataša
AU  - Kosanović, Darko
AU  - Marković, Smilja
AU  - Kachlik, Martin
AU  - Maca, Karel
AU  - Pavlović, Vladimir B.
PY  - 2019
UR  - http://dais.sanu.ac.rs/123456789/4558
AB  - Thermally activated processes in cordierite-based ceramics were investigated to determine the effect of the mechanical activation and the addition of TeO2 on kinetic and thermodynamic parameters of these processes. Using a combination of dilatometry and DTA measurements in the 100–1400 °C temperature range, it was established that both the mechanical activation and the addition of TeO2 have a significant effect on processes in cordierite-based ceramics. A combination of 5 mass% addition of TeO2 and mechanical activation for 40 min reduced the sintering temperature of cordierite ceramics to around 1100 °C. In addition, the analysis of DTA measurements of mechanically activated samples indicates that the mechanical activation leads to intensification of the cordierite formation through an increase in concentration of surface defects and an increase in grain contact surface in the initial powder.
PB  - Springer
T2  - Journal of Thermal Analysis and Calorimetry
T1  - Kinetics of thermally activated processes in cordierite-based ceramics
SP  - 2989
EP  - 2998
VL  - 138
DO  - 10.1007/s10973-018-7924-1
ER  - 
@article{
author = "Obradović, Nina and Blagojević, Vladimir A. and Filipović, Suzana and Đorđević, Nataša and Kosanović, Darko and Marković, Smilja and Kachlik, Martin and Maca, Karel and Pavlović, Vladimir B.",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/4558",
abstract = "Thermally activated processes in cordierite-based ceramics were investigated to determine the effect of the mechanical activation and the addition of TeO2 on kinetic and thermodynamic parameters of these processes. Using a combination of dilatometry and DTA measurements in the 100–1400 °C temperature range, it was established that both the mechanical activation and the addition of TeO2 have a significant effect on processes in cordierite-based ceramics. A combination of 5 mass% addition of TeO2 and mechanical activation for 40 min reduced the sintering temperature of cordierite ceramics to around 1100 °C. In addition, the analysis of DTA measurements of mechanically activated samples indicates that the mechanical activation leads to intensification of the cordierite formation through an increase in concentration of surface defects and an increase in grain contact surface in the initial powder.",
publisher = "Springer",
journal = "Journal of Thermal Analysis and Calorimetry",
title = "Kinetics of thermally activated processes in cordierite-based ceramics",
pages = "2989-2998",
volume = "138",
doi = "10.1007/s10973-018-7924-1"
}
1
1
1

The effect of mechanical activation on synthesis and properties of MgAl2O4 ceramics

Obradović, Nina; Fahrenholtz, William G.; Filipović, Suzana; Kosanović, Darko; Dapčević, A.; Đorđević, Antonije; Balać, Igor; Pavlović, Vladimir B.

(Elsevier, 2019)

TY  - JOUR
AU  - Obradović, Nina
AU  - Fahrenholtz, William G.
AU  - Filipović, Suzana
AU  - Kosanović, Darko
AU  - Dapčević, A.
AU  - Đorđević, Antonije
AU  - Balać, Igor
AU  - Pavlović, Vladimir B.
PY  - 2019
UR  - http://www.sciencedirect.com/science/article/pii/S0272884219306340
UR  - http://dais.sanu.ac.rs/123456789/5763
AB  - Magnesium aluminate, MgAl2O4 and other alumina-based spinels are ceramics with high hardness, high melting point and mechanical strenght. Spinels can also be used as dielectrics in microwave applications. The goal of this study was to examine the effects of mechanical activation and sintering temperatures on physico-chemical properties of spinel. MgAl2O4 was produced by solid state reaction between MgO and α-Al2O3. The starting powders were mixed by ball milling to homogenize without significant particle size reduction. Mechanical activation of mixed powders was performed in a high-energy planetary ball mill in air for 1 h. Powders were compacted at 300 MPa. Heat treatments were performed in air, at temperatures ranging from 1200 to 1600 °C with 2 h dwell time, to determine the amount of spinel formation as a function of temperature. Phase composition and microstructure of initial powders and heated samples were determined by means of X-ray diffraction, particle size analysis, and scanning electron microscopy. The influences of milling and consolidation parameters were studied by electrical measurements and mechanical characterization. The main conclusion of this study was that mechanical activation for 60 min initiated a mechano-chemical reaction, resulted in spinel formation at much lower temperatures than within non-activated powders, and indicated that final sintering stage started at much lower temperatures for activated powders. Changes in microstructure parameters, as a consequence of mechanical treatment and subsequent heating of investigated powder mixtures, strongly affect electrical and mechanical properties of the final ceramics.
PB  - Elsevier
T2  - Ceramics International
T1  - The effect of mechanical activation on synthesis and properties of MgAl2O4 ceramics
SP  - 12015
EP  - 12021
VL  - 45
IS  - 9
DO  - 10.1016/j.ceramint.2019.03.095
ER  - 
@article{
author = "Obradović, Nina and Fahrenholtz, William G. and Filipović, Suzana and Kosanović, Darko and Dapčević, A. and Đorđević, Antonije and Balać, Igor and Pavlović, Vladimir B.",
year = "2019",
url = "http://www.sciencedirect.com/science/article/pii/S0272884219306340, http://dais.sanu.ac.rs/123456789/5763",
abstract = "Magnesium aluminate, MgAl2O4 and other alumina-based spinels are ceramics with high hardness, high melting point and mechanical strenght. Spinels can also be used as dielectrics in microwave applications. The goal of this study was to examine the effects of mechanical activation and sintering temperatures on physico-chemical properties of spinel. MgAl2O4 was produced by solid state reaction between MgO and α-Al2O3. The starting powders were mixed by ball milling to homogenize without significant particle size reduction. Mechanical activation of mixed powders was performed in a high-energy planetary ball mill in air for 1 h. Powders were compacted at 300 MPa. Heat treatments were performed in air, at temperatures ranging from 1200 to 1600 °C with 2 h dwell time, to determine the amount of spinel formation as a function of temperature. Phase composition and microstructure of initial powders and heated samples were determined by means of X-ray diffraction, particle size analysis, and scanning electron microscopy. The influences of milling and consolidation parameters were studied by electrical measurements and mechanical characterization. The main conclusion of this study was that mechanical activation for 60 min initiated a mechano-chemical reaction, resulted in spinel formation at much lower temperatures than within non-activated powders, and indicated that final sintering stage started at much lower temperatures for activated powders. Changes in microstructure parameters, as a consequence of mechanical treatment and subsequent heating of investigated powder mixtures, strongly affect electrical and mechanical properties of the final ceramics.",
publisher = "Elsevier",
journal = "Ceramics International",
title = "The effect of mechanical activation on synthesis and properties of MgAl2O4 ceramics",
pages = "12015-12021",
volume = "45",
number = "9",
doi = "10.1016/j.ceramint.2019.03.095"
}
5
6
4

The effect of mechanical activation on synthesis and properties of MgAl2O4 ceramics

Obradović, Nina; Fahrenholtz, William G.; Filipović, Suzana; Kosanović, Darko; Dapčević, A.; Đorđević, Antonije; Balać, Igor; Pavlović, Vladimir B.

(Elsevier, 2019)

TY  - JOUR
AU  - Obradović, Nina
AU  - Fahrenholtz, William G.
AU  - Filipović, Suzana
AU  - Kosanović, Darko
AU  - Dapčević, A.
AU  - Đorđević, Antonije
AU  - Balać, Igor
AU  - Pavlović, Vladimir B.
PY  - 2019
UR  - http://www.sciencedirect.com/science/article/pii/S0272884219306340
UR  - http://dais.sanu.ac.rs/123456789/5272
AB  - Magnesium aluminate, MgAl2O4 and other alumina-based spinels are ceramics with high hardness, high melting point and mechanical strenght. Spinels can also be used as dielectrics in microwave applications. The goal of this study was to examine the effects of mechanical activation and sintering temperatures on physico-chemical properties of spinel. MgAl2O4 was produced by solid state reaction between MgO and α-Al2O3. The starting powders were mixed by ball milling to homogenize without significant particle size reduction. Mechanical activation of mixed powders was performed in a high-energy planetary ball mill in air for 1 h. Powders were compacted at 300 MPa. Heat treatments were performed in air, at temperatures ranging from 1200 to 1600 °C with 2 h dwell time, to determine the amount of spinel formation as a function of temperature. Phase composition and microstructure of initial powders and heated samples were determined by means of X-ray diffraction, particle size analysis, and scanning electron microscopy. The influences of milling and consolidation parameters were studied by electrical measurements and mechanical characterization. The main conclusion of this study was that mechanical activation for 60 min initiated a mechano-chemical reaction, resulted in spinel formation at much lower temperatures than within non-activated powders, and indicated that final sintering stage started at much lower temperatures for activated powders. Changes in microstructure parameters, as a consequence of mechanical treatment and subsequent heating of investigated powder mixtures, strongly affect electrical and mechanical properties of the final ceramics.
PB  - Elsevier
T2  - Ceramics International
T1  - The effect of mechanical activation on synthesis and properties of MgAl2O4 ceramics
SP  - 12015
EP  - 12021
VL  - 45
IS  - 9
DO  - 10.1016/j.ceramint.2019.03.095
ER  - 
@article{
author = "Obradović, Nina and Fahrenholtz, William G. and Filipović, Suzana and Kosanović, Darko and Dapčević, A. and Đorđević, Antonije and Balać, Igor and Pavlović, Vladimir B.",
year = "2019",
url = "http://www.sciencedirect.com/science/article/pii/S0272884219306340, http://dais.sanu.ac.rs/123456789/5272",
abstract = "Magnesium aluminate, MgAl2O4 and other alumina-based spinels are ceramics with high hardness, high melting point and mechanical strenght. Spinels can also be used as dielectrics in microwave applications. The goal of this study was to examine the effects of mechanical activation and sintering temperatures on physico-chemical properties of spinel. MgAl2O4 was produced by solid state reaction between MgO and α-Al2O3. The starting powders were mixed by ball milling to homogenize without significant particle size reduction. Mechanical activation of mixed powders was performed in a high-energy planetary ball mill in air for 1 h. Powders were compacted at 300 MPa. Heat treatments were performed in air, at temperatures ranging from 1200 to 1600 °C with 2 h dwell time, to determine the amount of spinel formation as a function of temperature. Phase composition and microstructure of initial powders and heated samples were determined by means of X-ray diffraction, particle size analysis, and scanning electron microscopy. The influences of milling and consolidation parameters were studied by electrical measurements and mechanical characterization. The main conclusion of this study was that mechanical activation for 60 min initiated a mechano-chemical reaction, resulted in spinel formation at much lower temperatures than within non-activated powders, and indicated that final sintering stage started at much lower temperatures for activated powders. Changes in microstructure parameters, as a consequence of mechanical treatment and subsequent heating of investigated powder mixtures, strongly affect electrical and mechanical properties of the final ceramics.",
publisher = "Elsevier",
journal = "Ceramics International",
title = "The effect of mechanical activation on synthesis and properties of MgAl2O4 ceramics",
pages = "12015-12021",
volume = "45",
number = "9",
doi = "10.1016/j.ceramint.2019.03.095"
}
5
6
4

Processing and properties of dense cordierite ceramics obtained through solid-state reaction and pressure-less sintering

Obradović, Nina; Pavlović, Vera P.; Kachlik, Martin; Maca, Karel; Olćan, Dragan; Đorđević, Antonije; Tshantshapanyan, Ani; Vlahović, Branislav; Pavlović, Vladimir B.

(Taylor and Francis, 2019)

TY  - JOUR
AU  - Obradović, Nina
AU  - Pavlović, Vera P.
AU  - Kachlik, Martin
AU  - Maca, Karel
AU  - Olćan, Dragan
AU  - Đorđević, Antonije
AU  - Tshantshapanyan, Ani
AU  - Vlahović, Branislav
AU  - Pavlović, Vladimir B.
PY  - 2019
UR  - http://dais.sanu.ac.rs/123456789/4557
AB  - Sintering of pure cordierite 2MgO:2Al2O3:5SiO2, and cordierite with the addition of 5 mass % TeO2 was studied. Green bodies were prepared from powder mixtures mechanically activated in a high-energy planetary mill, shaped by uniaxial (20 MPa) and cold isostatic pressing (1000 MPa). The pressure-less sintering of these specimens was performed at 1350°C for 1 h. High relative density over 95% of the theoretical value was obtained through solid-state reaction and pressure-less sintering of powder activated for 40 min, and for the first time reported in the literature. Phase composition and microstructures of sintered samples were determined by XRD and SEM, coupled with EDS mapping. The real part of the complex relative permittivity of the samples was measured at 200 MHz. The loss tangent of all samples was below the resolution of the measurement setup. A strong correlation between the relative permittivity and the density agrees with previously published data.
PB  - Taylor and Francis
T2  - Advances in Applied Ceramics
T1  - Processing and properties of dense cordierite ceramics obtained through solid-state reaction and pressure-less sintering
SP  - 241
EP  - 248
VL  - 118
IS  - 5
DO  - 10.1080/17436753.2018.1548150
ER  - 
@article{
author = "Obradović, Nina and Pavlović, Vera P. and Kachlik, Martin and Maca, Karel and Olćan, Dragan and Đorđević, Antonije and Tshantshapanyan, Ani and Vlahović, Branislav and Pavlović, Vladimir B.",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/4557",
abstract = "Sintering of pure cordierite 2MgO:2Al2O3:5SiO2, and cordierite with the addition of 5 mass % TeO2 was studied. Green bodies were prepared from powder mixtures mechanically activated in a high-energy planetary mill, shaped by uniaxial (20 MPa) and cold isostatic pressing (1000 MPa). The pressure-less sintering of these specimens was performed at 1350°C for 1 h. High relative density over 95% of the theoretical value was obtained through solid-state reaction and pressure-less sintering of powder activated for 40 min, and for the first time reported in the literature. Phase composition and microstructures of sintered samples were determined by XRD and SEM, coupled with EDS mapping. The real part of the complex relative permittivity of the samples was measured at 200 MHz. The loss tangent of all samples was below the resolution of the measurement setup. A strong correlation between the relative permittivity and the density agrees with previously published data.",
publisher = "Taylor and Francis",
journal = "Advances in Applied Ceramics",
title = "Processing and properties of dense cordierite ceramics obtained through solid-state reaction and pressure-less sintering",
pages = "241-248",
volume = "118",
number = "5",
doi = "10.1080/17436753.2018.1548150"
}
3
3
3

Effects of mechanical-activation and TiO2 addition on the behavior of two-step sintered steatite ceramics

Terzić, Anja; Obradović, Nina; Kosanović, Darko; Stojanović, Jovica; Đorđević, Antonije; Andrić, Ljubiša; Pavlović, Vladimir B.

(Elsevier, 2019)

TY  - JOUR
AU  - Terzić, Anja
AU  - Obradović, Nina
AU  - Kosanović, Darko
AU  - Stojanović, Jovica
AU  - Đorđević, Antonije
AU  - Andrić, Ljubiša
AU  - Pavlović, Vladimir B.
PY  - 2019
UR  - http://www.sciencedirect.com/science/article/pii/S0272884218329262
UR  - http://dais.sanu.ac.rs/123456789/4635
AB  - Steatite, as ceramic with composition predominantly resting on magnesium silicate, was produced from economic resources – talc, aluminosilicate clays, and either BaCO3 or feldspar as flux. Titanium dioxide was a doping agent. Four steatite mixtures were mechanically activated in a planetary ball mill for 30, 45 or 60 min, prior to the thermal treatment. Two-step sintering with initial phase set at 1350 °C and holding period conducted at 1250 °C was applied to initiate diffusion and prevent grain growth. Thereby, a high density ceramic material with low-porous submicron structure was acquired. The effects of TiO2 addition on densification, microstructure, and dielectric characteristics of steatites were monitored. The thermal stability of green mixtures was tested by differential thermal and thermogravimetric analyses. Changes in crystallinity and mineral phase composition were observed by the X-ray diffraction technique. Microstructural visualization with spatial arrangements of individual chemical elements on surface of the sintered ceramics was acquired by scanning electron microscopy accompanied with EDS mapping. In order to test the possibility of employment of the obtained steatites in insulation materials, electrical measurements were conducted by recording variations of the dielectric constant and loss tangent as a function of alternations in the mix-design and the mechanical activation period.
PB  - Elsevier
T2  - Ceramics International
T1  - Effects of mechanical-activation and TiO2 addition on the behavior of two-step sintered steatite ceramics
SP  - 3013
EP  - 3022
VL  - 45
IS  - 3
DO  - 10.1016/j.ceramint.2018.10.120
ER  - 
@article{
author = "Terzić, Anja and Obradović, Nina and Kosanović, Darko and Stojanović, Jovica and Đorđević, Antonije and Andrić, Ljubiša and Pavlović, Vladimir B.",
year = "2019",
url = "http://www.sciencedirect.com/science/article/pii/S0272884218329262, http://dais.sanu.ac.rs/123456789/4635",
abstract = "Steatite, as ceramic with composition predominantly resting on magnesium silicate, was produced from economic resources – talc, aluminosilicate clays, and either BaCO3 or feldspar as flux. Titanium dioxide was a doping agent. Four steatite mixtures were mechanically activated in a planetary ball mill for 30, 45 or 60 min, prior to the thermal treatment. Two-step sintering with initial phase set at 1350 °C and holding period conducted at 1250 °C was applied to initiate diffusion and prevent grain growth. Thereby, a high density ceramic material with low-porous submicron structure was acquired. The effects of TiO2 addition on densification, microstructure, and dielectric characteristics of steatites were monitored. The thermal stability of green mixtures was tested by differential thermal and thermogravimetric analyses. Changes in crystallinity and mineral phase composition were observed by the X-ray diffraction technique. Microstructural visualization with spatial arrangements of individual chemical elements on surface of the sintered ceramics was acquired by scanning electron microscopy accompanied with EDS mapping. In order to test the possibility of employment of the obtained steatites in insulation materials, electrical measurements were conducted by recording variations of the dielectric constant and loss tangent as a function of alternations in the mix-design and the mechanical activation period.",
publisher = "Elsevier",
journal = "Ceramics International",
title = "Effects of mechanical-activation and TiO2 addition on the behavior of two-step sintered steatite ceramics",
pages = "3013-3022",
volume = "45",
number = "3",
doi = "10.1016/j.ceramint.2018.10.120"
}

Effects of mechanical-activation and TiO2 addition on the behavior of two-step sintered steatite ceramics

Terzić, Anja; Obradović, Nina; Kosanović, Darko; Stojanović, Jovica; Đorđević, Antonije; Andrić, Ljubiša; Pavlović, Vladimir B.

(Elsevier, 2019)

TY  - JOUR
AU  - Terzić, Anja
AU  - Obradović, Nina
AU  - Kosanović, Darko
AU  - Stojanović, Jovica
AU  - Đorđević, Antonije
AU  - Andrić, Ljubiša
AU  - Pavlović, Vladimir B.
PY  - 2019
UR  - http://www.sciencedirect.com/science/article/pii/S0272884218329262
UR  - http://dais.sanu.ac.rs/123456789/4645
AB  - Steatite, as ceramic with composition predominantly resting on magnesium silicate, was produced from economic resources – talc, aluminosilicate clays, and either BaCO3 or feldspar as flux. Titanium dioxide was a doping agent. Four steatite mixtures were mechanically activated in a planetary ball mill for 30, 45 or 60 min, prior to the thermal treatment. Two-step sintering with initial phase set at 1350 °C and holding period conducted at 1250 °C was applied to initiate diffusion and prevent grain growth. Thereby, a high density ceramic material with low-porous submicron structure was acquired. The effects of TiO2 addition on densification, microstructure, and dielectric characteristics of steatites were monitored. The thermal stability of green mixtures was tested by differential thermal and thermogravimetric analyses. Changes in crystallinity and mineral phase composition were observed by the X-ray diffraction technique. Microstructural visualization with spatial arrangements of individual chemical elements on surface of the sintered ceramics was acquired by scanning electron microscopy accompanied with EDS mapping. In order to test the possibility of employment of the obtained steatites in insulation materials, electrical measurements were conducted by recording variations of the dielectric constant and loss tangent as a function of alternations in the mix-design and the mechanical activation period.
PB  - Elsevier
T2  - Ceramics International
T1  - Effects of mechanical-activation and TiO2 addition on the behavior of two-step sintered steatite ceramics
SP  - 3013
EP  - 3022
VL  - 45
IS  - 3
DO  - 10.1016/j.ceramint.2018.10.120
ER  - 
@article{
author = "Terzić, Anja and Obradović, Nina and Kosanović, Darko and Stojanović, Jovica and Đorđević, Antonije and Andrić, Ljubiša and Pavlović, Vladimir B.",
year = "2019",
url = "http://www.sciencedirect.com/science/article/pii/S0272884218329262, http://dais.sanu.ac.rs/123456789/4645",
abstract = "Steatite, as ceramic with composition predominantly resting on magnesium silicate, was produced from economic resources – talc, aluminosilicate clays, and either BaCO3 or feldspar as flux. Titanium dioxide was a doping agent. Four steatite mixtures were mechanically activated in a planetary ball mill for 30, 45 or 60 min, prior to the thermal treatment. Two-step sintering with initial phase set at 1350 °C and holding period conducted at 1250 °C was applied to initiate diffusion and prevent grain growth. Thereby, a high density ceramic material with low-porous submicron structure was acquired. The effects of TiO2 addition on densification, microstructure, and dielectric characteristics of steatites were monitored. The thermal stability of green mixtures was tested by differential thermal and thermogravimetric analyses. Changes in crystallinity and mineral phase composition were observed by the X-ray diffraction technique. Microstructural visualization with spatial arrangements of individual chemical elements on surface of the sintered ceramics was acquired by scanning electron microscopy accompanied with EDS mapping. In order to test the possibility of employment of the obtained steatites in insulation materials, electrical measurements were conducted by recording variations of the dielectric constant and loss tangent as a function of alternations in the mix-design and the mechanical activation period.",
publisher = "Elsevier",
journal = "Ceramics International",
title = "Effects of mechanical-activation and TiO2 addition on the behavior of two-step sintered steatite ceramics",
pages = "3013-3022",
volume = "45",
number = "3",
doi = "10.1016/j.ceramint.2018.10.120"
}