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Magnesium aluminum silicate (MgO–Al2O3–SiO2, MAS) glass-ceramic was prepared via sintering route. X-ray diffraction (XRD) analysis indicates the formation of multiphase compound with magnesium silicate fluoride and cordierite as major phases. Dielectric studies of the compound shows a strong frequency dispersion of permittivity in the low frequency region followed by a nearly frequency-independent behavior in the high frequency region. The presence of alkali ions (K+) in MAS glass-ceramic results in higher dielectric constant and higher losses. Dielectric loss (tanδ) seems to be reduced at higher frequencies after reaching the instrumental saturation at 1 kHz. Electrical properties of the material have been studied using a complex impedance spectroscopy (CIS) technique in a wide temperature (30–500 ℃) and frequency (100 Hz–5 MHz) ranges. The complex impedance plots reveal the contribution of bulk as well as grain boundary effects in it. The bulk resistance, evaluated from complex impedance spectrum, has been observed to decrease with the rise in temperature, showing a typical negative temperature coefficient of resistance (NTCR) behavior. The smaller activation energy (Ea) of the compound within moderate temperature range suggests the presence of ions (K+ and F-) and singly ionized oxygen vacancies in the conduction process. The nature of variation of the electrical conductivity, and the values of activation energy of different temperature regions, suggest that the conduction process is of mixed type.


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Dielectric and impedance properties of sintered magnesium aluminum silicate glass-ceramic

Show Author's information Abhijit PRASAD*( )Amitabha BASU
Department of Applied Physics, Indian School of Mines, Dhanbad 826004, India

Abstract

Magnesium aluminum silicate (MgO–Al2O3–SiO2, MAS) glass-ceramic was prepared via sintering route. X-ray diffraction (XRD) analysis indicates the formation of multiphase compound with magnesium silicate fluoride and cordierite as major phases. Dielectric studies of the compound shows a strong frequency dispersion of permittivity in the low frequency region followed by a nearly frequency-independent behavior in the high frequency region. The presence of alkali ions (K+) in MAS glass-ceramic results in higher dielectric constant and higher losses. Dielectric loss (tanδ) seems to be reduced at higher frequencies after reaching the instrumental saturation at 1 kHz. Electrical properties of the material have been studied using a complex impedance spectroscopy (CIS) technique in a wide temperature (30–500 ℃) and frequency (100 Hz–5 MHz) ranges. The complex impedance plots reveal the contribution of bulk as well as grain boundary effects in it. The bulk resistance, evaluated from complex impedance spectrum, has been observed to decrease with the rise in temperature, showing a typical negative temperature coefficient of resistance (NTCR) behavior. The smaller activation energy (Ea) of the compound within moderate temperature range suggests the presence of ions (K+ and F-) and singly ionized oxygen vacancies in the conduction process. The nature of variation of the electrical conductivity, and the values of activation energy of different temperature regions, suggest that the conduction process is of mixed type.

Keywords:

glass-ceramic, conductivity, dielectric properties, electrical properties
Received: 18 September 2012 Revised: 05 February 2013 Accepted: 06 February 2013 Published: 06 April 2013 Issue date: March 2013
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Publication history
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Publication history

Received: 18 September 2012
Revised: 05 February 2013
Accepted: 06 February 2013
Published: 06 April 2013
Issue date: March 2013

Copyright

© The author(s) 2013

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Open Access: This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.

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