Effect of porosity on dielectric properties of ZnO ceramics
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2020
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In this study we investigated the effect of porosity level on the dielectric properties and conductivity of ZnO
ceramic samples sintered by pressure-less solid-state reaction method. The relative permittivity ( r ) and, tangent
loss value decreased gradually with increasing porosity, being 1.9 × 105 and 35.6 × 103 for sample with low
porosity and high porosity level, respectively at room temperature. Also the tangent loss decreases with increasing porosity level being quite high (∼102
) at low frequencies and, low (∼10−1) at high frequencies. The
complex part of the relative permittivity results could be fitted to the Maxwell-Wagner (MW) model suggesting a
poly-dispersive relaxation time. The frequency dependence-ac conductivity determined by means of dielectric
data was strongly dependent of the porosity level. It decreases sharply with increasing porosity level is frequency
independent- up to ∼104 − 105 Hz followed by an abrupt increase at higher frequencies. These data were
discussed in terms ZnO defects such as Zn interstitial and oxygen vacancies present in the grain boundaries.
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Porosity level, Dielectric permittivity, ZnO ceramics
Citação
SILVA, Raphael Lucas de Sousa e; FRANCO, A. Effect of porosity on dielectric properties of ZnO ceramics. Journal of the European Ceramic Society, Amsterdam, v. 40, n. 4, p. 1307-1311, 2020. DOI: 10.1016/j.jeurceramsoc.2019.12.032. Disponível em: https://www.sciencedirect.com/science/article/pii/S0955221919308763. Acesso em: 4 set. 2023.