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

2019
Authors
Obradović, Nina
Fahrenholtz, William G.

Filipović, Suzana

Kosanović, Darko

Dapčević, Aleksandra

Đorđević, Antonije
Balać, Igor
Pavlović, Vladimir B.

Article (Published version)

Metadata
Show full item recordAbstract
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 alpha-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 degrees 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 analysi...s, 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.
Keywords:
Mechanical activation / Sintering / Microstructure / Electrical properties / Mechanical properties / SpinelSource:
Ceramics International, 2019, 45, 9, 12015-12021Publisher:
- Elsevier Sci Ltd, Oxford
Funding / projects:
- Directed synthesis, structure and properties of multifunctional materials (RS-172057)
- Zero- to Three-Dimensional Nanostructures for Application in Electronics and Renewable Energy Sources: Synthesis, Characterization and Processing (RS-45007)
- Synthesis, processing and applications of nanostructured multifunctional materials with defined properties (RS-45019)
DOI: 10.1016/j.ceramint.2019.03.095
ISSN: 0272-8842
WoS: 000466253500111
Scopus: 2-s2.0-85062915610
Institution/Community
Tehnološko-metalurški fakultetTY - JOUR AU - Obradović, Nina AU - Fahrenholtz, William G. AU - Filipović, Suzana AU - Kosanović, Darko AU - Dapčević, Aleksandra AU - Đorđević, Antonije AU - Balać, Igor AU - Pavlović, Vladimir B. PY - 2019 UR - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4264 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 alpha-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 degrees 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 Sci Ltd, Oxford T2 - Ceramics International T1 - The effect of mechanical activation on synthesis and properties of MgAl2O4 ceramics EP - 12021 IS - 9 SP - 12015 VL - 45 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, Aleksandra and Đorđević, Antonije and Balać, Igor and Pavlović, Vladimir B.", year = "2019", 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 alpha-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 degrees 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 Sci Ltd, Oxford", journal = "Ceramics International", title = "The effect of mechanical activation on synthesis and properties of MgAl2O4 ceramics", pages = "12021-12015", number = "9", volume = "45", doi = "10.1016/j.ceramint.2019.03.095" }
Obradović, N., Fahrenholtz, W. G., Filipović, S., Kosanović, D., Dapčević, A., Đorđević, A., Balać, I.,& Pavlović, V. B.. (2019). The effect of mechanical activation on synthesis and properties of MgAl2O4 ceramics. in Ceramics International Elsevier Sci Ltd, Oxford., 45(9), 12015-12021. https://doi.org/10.1016/j.ceramint.2019.03.095
Obradović N, Fahrenholtz WG, Filipović S, Kosanović D, Dapčević A, Đorđević A, Balać I, Pavlović VB. The effect of mechanical activation on synthesis and properties of MgAl2O4 ceramics. in Ceramics International. 2019;45(9):12015-12021. doi:10.1016/j.ceramint.2019.03.095 .
Obradović, Nina, Fahrenholtz, William G., Filipović, Suzana, Kosanović, Darko, Dapčević, Aleksandra, Đorđević, Antonije, Balać, Igor, Pavlović, Vladimir B., "The effect of mechanical activation on synthesis and properties of MgAl2O4 ceramics" in Ceramics International, 45, no. 9 (2019):12015-12021, https://doi.org/10.1016/j.ceramint.2019.03.095 . .