Electrical degradation characteristics of Low Voltage Zinc Oxide Varistor subjected to AC Switching Surges

In the present, varistor ceramics through the combination of zinc oxide (ZnO) with a perovskite material have become widespread because of their unique properties for a wide range of applications in electronic protection devices. Low-voltage zinc oxide (ZnO) varistors with fast response and highly nonlinear electrical properties for overvoltage protection in an integrated circuit are increasingly significant in the application of low-voltage electronics. The present study highlights the interaction between barium titanate (BaTiO3 ) and ZnO varistors through the employment of solid-state reaction method in the production of low-voltage varistors. The effects of BaTiO3 on the microstructure of ZnO varistors were analyzed through scanning electron microscopy (SEM), energy dispersive X-ray analysis spectroscopy (EDS) and X-ray diffraction (XRD). The EDS analysis and XRD measurements suggest the presence of ZnO and BaTiO3 phases. The electrical properties of BaTiO3 -doped ZnO varistors were examined based on the current density-electric field (J-E) characteristics measurement. The varistor properties showed the nonlinear coefficient (α) from 1.8 to 4.8 with the barrier height (φB) ranged from 0.70 to 0.88 eV. The used of BaTiO3 additive in ZnO varistors produced varistor voltages of 4.7 to 14.1 V/mm with the voltage per grain boundary (Vgb) was measured in the ranges 0.03 to 0.05 V. The lowest leakage current density was 348 µA/cm2 , obtained at the samples containing 12 wt.% BaTiO3 with high barrier height. The reduction in barrier height with increasing BaTiO3 content was associated with the excessive amount of BaTiO3 phase, hence cause the deterioration of active grain boundary due to the variation of oxygen (O) vacancies in the grain boundary.

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Gradient structure design of zinc oxide varistor microsphere composites for efficient electric field grading

Composites Part A Applied Science and Manufacturing ◽

10.1016/j.compositesa.2021.106731 ◽

2021 ◽

pp. 106731

Author(s):

Xiaolei Zhao ◽

Pengfei Meng ◽

Xiao Yang ◽

Zhikang Yuan ◽

Jun Hu ◽

...

Keyword(s):

Zinc Oxide ◽

Electric Field ◽

Structure Design ◽

Gradient Structure ◽

Zinc Oxide Varistor

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Microstructure and Crystal Phases of Praseodymium Oxides in Zinc Oxide Varistor Ceramics

Journal of the American Ceramic Society ◽

10.1111/j.1151-2916.1996.tb08986.x ◽

1996 ◽

Vol 79 (9) ◽

pp. 2379-2384 ◽

Cited By ~ 114

Author(s):

Yih-Shing Lee ◽

Kao-Shiang Liao ◽

Tseung-Yuen Tseng

Keyword(s):

Zinc Oxide ◽

Crystal Phases ◽

Zinc Oxide Varistor

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Fabrication of Bismuth-Based Zinc Oxide Varistors with High Varistor Voltage by Addition of Tin and Yttrium Oxides

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.582.198 ◽

2013 ◽

Vol 582 ◽

pp. 198-201

Author(s):

Yosuke Tokoro ◽

Takayuki Watanabe ◽

Yuuki Sato ◽

Shinzo Yoshikado

Keyword(s):

Zinc Oxide ◽

Leakage Current ◽

Yttrium Oxide ◽

Tin Oxide ◽

Molar Ratio ◽

Low Leakage ◽

Electrical Degradation ◽

Low Leakage Current ◽

Zno Varistors ◽

Zinc Oxide Varistors

The effects of the addition of tin oxide (SnO2) and yttrium oxide (Y2O3) to bismuth (Bi)-manganese (Mn)-cobalt (Co)-silicon (Si)-chromium (Cr)-nickel (Ni)-added zinc oxide (ZnO) varistors (a basic varistor) on the varistor voltage, resistance to electrical degradation, and leakage current were investigated. The addition of SnO2increased both the varistor voltage and the resistance to electrical degradation. However, simultaneous addition of both SnO2and Y2O3increased the varistor voltage but the resistance to electrical degradation deteriorated. ZnO varistors with varistor voltage over approximately 520 V/mm, excellent resistance to electrical degradation, and low leakage current could be obtained by adding SnO2with SnO2-to-ZnO molar ratio of approximately 1:10 to the basic varistor.

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