Open AccessElectrical Parameters of SnO2 Based Varistor Ceramics with CaO and BaO Additions
Author(s) -
A.V. Gaponov,
O.V. Vorobiov,
A.M. Vasyliev
Publication year - 2016
Publication title -
fìzika ì hìmìâ tverdogo tìla
Language(s) - English
Resource type - Journals
eISSN - 2309-8589
pISSN - 1729-4428
DOI - 10.15330/pcss.17.1.81-87
Subject(s) - varistor , materials science , electric field , ceramic , electrical resistivity and conductivity , dielectric , permittivity , grain boundary , grain size , temperature coefficient , composite material , activation energy , conductivity , thermal conduction , mineralogy , electrical resistance and conductance , condensed matter physics , microstructure , electrical engineering , chemistry , voltage , optoelectronics , physics , organic chemistry , quantum mechanics , engineering
In the tested SnO2-Co3O4-Nb2O5-Cr2O3-CuO varistor ceramics the adding of CaO or BaO oxides leads to the decrease of the electric conductivity in the low electric field and correlated increase of the potential barrier height at the SnO2 grain boundaries (from 0.7 to 1.0 eV). The coordinated changes of electrical parameters with the increase of the burning temperature from 1520 to 1620 К (the increase of the linear shrinkage, a grain size, an electric conductivity, a nonlinear coefficient , a normalized nonlinear coefficient , a dielectric permittivity and the decrease of the qualifying electric field E1, an activation energy of electric conduction and a grain specific resistance) prove the barrier mechanism of electric conductivity in the SnO2 based ceramics. The highest data and = 0.02 cm·V-1 has ceramics with CaO addition baked at 1620 K. According to the impulse experimental data in the high electric field the increase of burning temperature causes the increase of SnO2 grain average size and the decrease of their grain specific resistance . The obtained value = 1.1 Ohm·cm for SnO2-Co3O4-Nb2O5-Cr2O3-CuO ceramics is the lowest among those found in SnO2 based ceramics.