Ba0.75Sr0.25 Al2Si2O8 (BSAS) ceramic was synthetized starting from a (Ba, Sr)-exchanged zeolite A. The substitution of Ba with Sr promoted the transformation of hexacelsian to monocelsian, which was attained by a 5 h thermal treatment at 1200 °C. BSAS systems were structurally and dielectrically characterized. In particular, the evaluation of dielectric properties was performed by impedance spectroscopy in a.c. The study of the dielectric and the spectroscopic characteristic was investigated in the frequency range (100 Hz - 1 MHz). The dependence of the dielectric constant on the frequency has been explained on the basis of the mechanism Maxwell-Wagner, comparing BSAS systems with commonly used ceramic materialsin radome manufacturing, such as fused silica (SiO2) and silicon nitride (Si3N4).Electrochemical Impedance Spettroscopy (EIS) also provides useful information about the microstructure of the ceramic materials. The curve of permittivity vs frequency showedthat the BSAS has a constant performance in the frequency range investigated with lower value of permittivity compared to the other materials investigated.

Dielectric properties of monoclinic (Ba, Sr)-celsian obtained by thermal treatment of (Ba, Sr)-exchanged zeolite A

Marzocchi, Vincenza;Capasso, Ilaria;Scherillo, Fabio;Squillace, Antonino;Caputo, Domenico;Liguori, Barbara
2017

Abstract

Ba0.75Sr0.25 Al2Si2O8 (BSAS) ceramic was synthetized starting from a (Ba, Sr)-exchanged zeolite A. The substitution of Ba with Sr promoted the transformation of hexacelsian to monocelsian, which was attained by a 5 h thermal treatment at 1200 °C. BSAS systems were structurally and dielectrically characterized. In particular, the evaluation of dielectric properties was performed by impedance spectroscopy in a.c. The study of the dielectric and the spectroscopic characteristic was investigated in the frequency range (100 Hz - 1 MHz). The dependence of the dielectric constant on the frequency has been explained on the basis of the mechanism Maxwell-Wagner, comparing BSAS systems with commonly used ceramic materialsin radome manufacturing, such as fused silica (SiO2) and silicon nitride (Si3N4).Electrochemical Impedance Spettroscopy (EIS) also provides useful information about the microstructure of the ceramic materials. The curve of permittivity vs frequency showedthat the BSAS has a constant performance in the frequency range investigated with lower value of permittivity compared to the other materials investigated.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/700919
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