Open AccessElectrical properties of ZnO varistors prepared by direct mixing of constituent phases
Author(s) -
M. Žunić,
Zorica Branković,
Goran Branković
Publication year - 2006
Publication title -
science of sintering/science of sintering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.309
H-Index - 25
eISSN - 1820-7413
pISSN - 0350-820X
DOI - 10.2298/sos0602161z
Subject(s) - varistor , materials science , spinel , grain boundary , mixing (physics) , dielectric spectroscopy , electrical resistivity and conductivity , analytical chemistry (journal) , characterization (materials science) , mineralogy , voltage , composite material , microstructure , chemistry , metallurgy , electrical engineering , nanotechnology , electrode , physics , quantum mechanics , electrochemistry , chromatography , engineering
Varistor samples containing different amounts of constituent phases were prepared by direct mixing of constituent phases. Detailed electrical characterization was performed to explain the influence of minor phases (spinel and intergranular phases) on overall properties. Characterization included investigation of the non-linear coefficients (α), breakdown electric field (EB), leakage currents (JL), grain boundary barrier hight (ΦB) and constant β from current-voltage characteristics, as well as calculation of activation energies for conduction (EA) from ac impedance spectroscopy in the temperature interval 30-410°C. Varistors sintered at 1100 °C for 1 h showed pronounced differences in electrical properties depending on relative molar ratios of the phases. Results were discussed in the sense of possible reduction of the content of minor phases in ZnO varistors