Effect of Thermal Annealing on Electrical Degradation Characteristics of Sb2O3-Bi-Mn-Co-Doped ZnO Varistors

Masayuki Takada; Yuuki Sato; Shinzo Yoshikado

doi:10.4028/www.scientific.net/KEM.421-422.525

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Preparation of Barium Titanate Nanoparticle Thin Films by the Electrophoretic Deposition Method Using Polyacrylic Acid as a Charge-Compensating Agent
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Preparation of Barium Titanate and Strontium Titanate Nanocube Particles and their Accumulation Using Smart Glue
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Relaxation Phenomena of MgCuZn Ferrites
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Effect of Thermal Annealing on Electrical Degradation Characteristics of Sb₂O₃-Bi-Mn-Co-Doped ZnO Varistors
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The Effect of Reoxidation on Thermal Shock Resistance of SrTiO₃-Based Varistors
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Millimeter Wave Sintering of AlN Ceramics for Heat Sink Application
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Thermophysical Behaviour of Crystalline Halides with Temperature
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High Frequency Characteristic of Elements Substituted Hexagonal Ferrites
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Effect of Thermal Annealing on Electrical Degradation Characteristics of Sb₂O₃-Bi-Mn-Co-Doped ZnO Varistors

Abstract:

The effects of thermal annealing on the electrical degradation of Sb2O3-Bi-Mn-Co-doped ZnO varistors were investigated. For samples with 0.04 mol% Sb2O3 or more, the nonlinearity index  of the voltage-current (V-I) characteristics after electrical degradation increased upon annealing. More-over, the value of  after electrical degradation was proportional to the full width at half maximum (FWHM) of the X-ray diffraction peak for Zn2.33Sb0.67O4-type spinel particles under various annealing conditions. The added Sb2O3 did not dissolve in the ZnO grains but became segregated at grain boundaries. Therefore, it is speculated that the increase in the FWHM of the spinel particles is due to an increase in the numbers of fine spinel particles at grain boundaries and triple points during annealing. Furthermore, it is suggested that the improvement in the electrical degradation upon annealing is due to a decrease in the mobility of oxide ions or Zn2+ ions owing to their being blocked by uniformly distributed fine spinel particles at grain boundaries.