Electrical and mechanical properties of alumina doped with transition metal oxides sintered at 1400°C
Authors
Filipović, SuzanaObradović, Nina
Marković, Smilja
Balać, Igor
Đorđević, Antonije
Pavlović, Vladimir B.
Conference object (Published version)
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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.
Keywords:
alumina / corundum / sintering / dopants / transition metal oxidesSource:
Abstract Book / XVI Conference and Exhibition of the European Ceramic Society XVI ECerS Conference, Torino, 16-20 June 2019, 2019, 682-682Publisher:
- Societa ceramica italiana
- Politecnico di Torino
Funding / projects:
- Directed synthesis, structure and properties of multifunctional materials (RS-MESTD-Basic Research (BR or ON)-172057)
Institution/Community
Институт техничких наука САНУ / Institute of Technical Sciences of SASATY - CONF AU - Filipović, Suzana AU - Obradović, Nina AU - Marković, Smilja AU - Balać, Igor AU - Đorđević, Antonije AU - Pavlović, Vladimir B. PY - 2019 UR - https://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 UR - https://hdl.handle.net/21.15107/rcub_dais_7025 ER -
@conference{ author = "Filipović, Suzana and Obradović, Nina and Marković, Smilja and Balać, Igor and Đorđević, Antonije and Pavlović, Vladimir B.", year = "2019", 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", url = "https://hdl.handle.net/21.15107/rcub_dais_7025" }
Filipović, S., Obradović, N., Marković, S., Balać, I., Đorđević, A.,& Pavlović, V. B.. (2019). Electrical and mechanical properties of alumina doped with transition metal oxides sintered at 1400°C. in Abstract Book / XVI Conference and Exhibition of the European Ceramic Society XVI ECerS Conference, Torino, 16-20 June 2019 Societa ceramica italiana., 682-682. https://hdl.handle.net/21.15107/rcub_dais_7025
Filipović S, Obradović N, Marković S, Balać I, Đorđević A, Pavlović VB. Electrical and mechanical properties of alumina doped with transition metal oxides sintered at 1400°C. in Abstract Book / XVI Conference and Exhibition of the European Ceramic Society XVI ECerS Conference, Torino, 16-20 June 2019. 2019;:682-682. https://hdl.handle.net/21.15107/rcub_dais_7025 .
Filipović, Suzana, Obradović, Nina, Marković, Smilja, Balać, Igor, Đorđević, Antonije, Pavlović, Vladimir B., "Electrical and mechanical properties of alumina doped with transition metal oxides sintered at 1400°C" in Abstract Book / XVI Conference and Exhibition of the European Ceramic Society XVI ECerS Conference, Torino, 16-20 June 2019 (2019):682-682, https://hdl.handle.net/21.15107/rcub_dais_7025 .