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

Ba0.75Sr0.25Al2Si2O8 (BSAS) ceramic was synthetized starting from a (Ba, Sr)-exchanged zeolite A. The substitution of Ba with Sr helped 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 carried out 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 other ceramic materials commonly used in radome manufacturing, such as fused silica (SiO2) and silicon nitride (Si3N4). Electrochemical Impedance Spectroscopy (EIS) was used in order to collect additional information about the microstructure of the ceramic materials. The curve of permittivity versus frequency showed that the BSAS has a constant performance in the frequency range investigated with lower value of permittivity compared to the other materials investigated. This behavior is particularly interesting for radome application. © 2017 American Scientific Publishers All rights reserved.