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 a solid-state reaction between MgO and α-Al2O3 powders. Mechanical activation for 30 min in a planetary ball mill was used to increase the reactivity of powders. Yttrium oxide and graphene were added to prevent abnormal grain growth during sintering. Samples were sintered by hot pressing under vacuum at 1450 °C. Phase composition and microstructure of sintered specimens were characterized by X-ray powder diffraction and scanning electron microscopy. Rietveld analysis revealed 100% pure spinel phase in all sintered specimens, and a decrease in crystallite size with the addition of yttria or graphene. Density measurements indicated that the mechanically activated specimen reached 99.6% relative density. Furthermore, the highest solar absorbance and highest spectral selectivity as a function of temperature were det...ected for the mechanically activated specimen with graphene addition. Mechanical activation is an efficient method to improve densification of MgAl2O4 prepared from mixed oxide powders, while additives improve microstructure and optical properties.
TY - JOUR
AU - Obradović, Nina
AU - Fahrenholtz, William G.
AU - Corlett, Cole
AU - Filipović, Suzana
AU - Nikolić, Marko
AU - Marinković, Bojan A.
AU - Failla, Simone
AU - Sciti, Diletta
AU - Di Rosa, Daniele
AU - Sani, Elisa
PY - 2021
UR - https://dais.sanu.ac.rs/123456789/12431
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 a solid-state reaction between MgO and α-Al2O3 powders. Mechanical activation for 30 min in a planetary ball mill was used to increase the reactivity of powders. Yttrium oxide and graphene were added to prevent abnormal grain growth during sintering. Samples were sintered by hot pressing under vacuum at 1450 °C. Phase composition and microstructure of sintered specimens were characterized by X-ray powder diffraction and scanning electron microscopy. Rietveld analysis revealed 100% pure spinel phase in all sintered specimens, and a decrease in crystallite size with the addition of yttria or graphene. Density measurements indicated that the mechanically activated specimen reached 99.6% relative density. Furthermore, the highest solar absorbance and highest spectral selectivity as a function of temperature were detected for the mechanically activated specimen with graphene addition. Mechanical activation is an efficient method to improve densification of MgAl2O4 prepared from mixed oxide powders, while additives improve microstructure and optical properties.
PB - Basel : MDPI AG
T2 - Materials
T1 - Microstructural and Optical Properties of MgAl2O4 Spinel: Effects of Mechanical Activation, Y2O3 and Graphene Additions
SP - 7674
VL - 14
IS - 24
DO - 10.3390/ma14247674
UR - https://hdl.handle.net/21.15107/rcub_dais_12431
ER -
@article{
author = "Obradović, Nina and Fahrenholtz, William G. and Corlett, Cole and Filipović, Suzana and Nikolić, Marko and Marinković, Bojan A. and Failla, Simone and Sciti, Diletta and Di Rosa, Daniele and Sani, Elisa",
year = "2021",
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 a solid-state reaction between MgO and α-Al2O3 powders. Mechanical activation for 30 min in a planetary ball mill was used to increase the reactivity of powders. Yttrium oxide and graphene were added to prevent abnormal grain growth during sintering. Samples were sintered by hot pressing under vacuum at 1450 °C. Phase composition and microstructure of sintered specimens were characterized by X-ray powder diffraction and scanning electron microscopy. Rietveld analysis revealed 100% pure spinel phase in all sintered specimens, and a decrease in crystallite size with the addition of yttria or graphene. Density measurements indicated that the mechanically activated specimen reached 99.6% relative density. Furthermore, the highest solar absorbance and highest spectral selectivity as a function of temperature were detected for the mechanically activated specimen with graphene addition. Mechanical activation is an efficient method to improve densification of MgAl2O4 prepared from mixed oxide powders, while additives improve microstructure and optical properties.",
publisher = "Basel : MDPI AG",
journal = "Materials",
title = "Microstructural and Optical Properties of MgAl2O4 Spinel: Effects of Mechanical Activation, Y2O3 and Graphene Additions",
pages = "7674",
volume = "14",
number = "24",
doi = "10.3390/ma14247674",
url = "https://hdl.handle.net/21.15107/rcub_dais_12431"
}
Obradović, N., Fahrenholtz, W. G., Corlett, C., Filipović, S., Nikolić, M., Marinković, B. A., Failla, S., Sciti, D., Di Rosa, D.,& Sani, E.. (2021). Microstructural and Optical Properties of MgAl2O4 Spinel: Effects of Mechanical Activation, Y2O3 and Graphene Additions. in Materials
Basel : MDPI AG., 14(24), 7674.
https://doi.org/10.3390/ma14247674
https://hdl.handle.net/21.15107/rcub_dais_12431
Obradović N, Fahrenholtz WG, Corlett C, Filipović S, Nikolić M, Marinković BA, Failla S, Sciti D, Di Rosa D, Sani E. Microstructural and Optical Properties of MgAl2O4 Spinel: Effects of Mechanical Activation, Y2O3 and Graphene Additions. in Materials. 2021;14(24):7674.
doi:10.3390/ma14247674
https://hdl.handle.net/21.15107/rcub_dais_12431 .
Obradović, Nina, Fahrenholtz, William G., Corlett, Cole, Filipović, Suzana, Nikolić, Marko, Marinković, Bojan A., Failla, Simone, Sciti, Diletta, Di Rosa, Daniele, Sani, Elisa, "Microstructural and Optical Properties of MgAl2O4 Spinel: Effects of Mechanical Activation, Y2O3 and Graphene Additions" in Materials, 14, no. 24 (2021):7674,
https://doi.org/10.3390/ma14247674 .,
https://hdl.handle.net/21.15107/rcub_dais_12431 .
