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Structural and dielectric properties of sintered ZnAl 2 O 4 ceramics
P K HALDAR, , T K PARYA
Published in -
2012
Volume: 61
   
Issue: 6
Pages: 363 - 366
Abstract
Zinc aluminate spinel (ZnAl 2 O 4 ) precursor powder with the molar ratio of ZnO : Al 2 O3 as 1 : 1 has been synthesized through a co-precipitation route from which dense ZnAl 2 O 4 -ceramic is prepared by sintering uniaxially pressed pellets at a temperature of 1450 °C. The X-ray diffraction pattern of the sintered body clearly reveals the formation of the welldefined crystalline single ZnAl 2 O 4 spinel phase. Microstructural features using scanning electron microscopy (SEM) confirms the uniformly distributed fine grain microstructure of sintered ZnAl 2 O 4 bodies. Dielectric properties viz. relative permittivity, capacitance and ac conductivity were measured on sintered ZnAl 2 O 4 compacts. The ac conductivity, capacitance and loss factor of the sintered compacts were recorded in the frequency range from 100 kHz-3 MHz, as well as in the wide temperature range of -20-160 °C. The Maxwell-Wagner type interfacial polarization exists in ZnAl 2 O 4 spinel material. Hopping of electrons at the grain boundary of ZnAl 2 O 4 particles by means of quantum mechanical tunnelling is responsible for the increase of ac conductivity as a function of both temperature and frequency.
About the journal
JournalInterCeram: International Ceramic Review
Publisher-
ISSN0020-5214
Open AccessNo