Electrical Properties and Kinetic of Crystalline Grain Growth of Low-voltage ZnO Varistor Doped with Zn-B Glass

The effect of Ho2O3 doping on the electrical properties and microstructure of ZnO base varistor was investigated. It was found that Ho2O3 is an effective dopant for increasing the breakdown electric filed. The Ho2O3 doping can also improve the nonlinear performance both in low and high current area. But excessive doping of Ho2O3 will decrease the withstanding surge current. With 0.8mol% Ho2O3 doping, the varistor samples exhibit a breakdown voltage of about 400V/mm, a nonlinear coefficient of 80 and the withstanding surge current of 8/20μs, waveshape is higher than 5kA. Ho2O3 dopant can hinder ZnO grain growth and make the crystal grains more uniform.

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Microstructural and Nonlinear Properties of Zn-V-Mn-Nb-O Varistor Ceramics with Gd2O3 Substitution for Low Voltage Application

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.268.181 ◽

2017 ◽

Vol 268 ◽

pp. 181-185 ◽

Cited By ~ 1

Author(s):

Nor Hasanah Isa ◽

Zakaria Azmi ◽

Raba’ah Syahidah Azis ◽

Zahid Rizwan

Keyword(s):

Electrical Properties ◽

Grain Growth ◽

Leakage Current Density ◽

Current Density ◽

Triple Point ◽

Low Voltage ◽

Nonlinear Coefficient ◽

Electrical Field ◽

Nonlinear Properties ◽

Voltage Application

The effect of Gd2O3 substitution on the microstructural and electrical properties of Zn-V-Mn-Nb-O varistor ceramics sintered at 900°C was investigated. XRD, SEM, and EDAX results show that the GdMnO3 and GdVO4 phases formed at the grain boundaries and triple point junctions. Gd2O3 substitution inhibited the grain growth from 3.85 to 3.06 μm and increased the sintered ceramics density from 5.12 to 5.19 g/cm3.The samples containing the amount of 0.03 mol% Gd2O3 exhibit an optimum nonlinear coefficient α value which is 9.91, highest breakdown electrical field which is 88.48 V/mm and lowest leakage current density which is 0.11 mA/cm2 in low voltage application.

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Study on the Electrical Properties and the Ac Conductance Response of ZnO-Based Varistor

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1070-1072.625 ◽

2014 ◽

Vol 1070-1072 ◽

pp. 625-629

Author(s):

Xue Tong Zhao ◽

Rui Jin Liao ◽

Jian Ying Li

Keyword(s):

Activation Energy ◽

Grain Size ◽

Electrical Properties ◽

Electric Field ◽

Grain Growth ◽

Relaxation Peak ◽

Breakdown Electric Field ◽

Zno Varistor ◽

Ac Conductance

ZnO-based varistor ceramics with different recipes were prepared in this research. It was found that the grain growth was restrained with the addition of Ba2+. SEM results indicated that the grain size of ZnO varistor ceramics with Ba2+ was reduced to 4.7 μm. Correspondingly, the breakdown electric field of the ZnO varistor samples were extremely enhanced to 8730 V/cm. The results of ac conductance response showed that two relaxation peak 1 and 2 with activation energy at about 0.24 eV and 0.36 eV were observed in 100-250 K, which were not affected by additives. However, a new conductance relaxation peak 3 in 300-450 K for sample B and C can be found, whose activation energy were varied from 0.55 eV to 0.65 eV with the addition of Ba2+. It was put forward that the electrical properties of ZnO varistor ceramics may be associated with the conductance relaxation peak 3.

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Influence of process variables on the microstructure and electrical properties of low-voltage ZnO varistor

10.1117/12.385530 ◽

2000 ◽

Author(s):

Congchun Zhang ◽

Dong-xiang Zhou ◽

Shuping Gong

Keyword(s):

Electrical Properties ◽

Low Voltage ◽

Process Variables ◽

Zno Varistor

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Tailoring electrical properties of multiple dopant-based ZnO varistor by doping with yttrium, gallium, and indium

Materials Letters ◽

10.1016/j.matlet.2017.08.041 ◽

2017 ◽

Vol 209 ◽

pp. 413-416 ◽

Cited By ~ 8

Author(s):

Pengfei Meng ◽

Xiao Yang ◽

Jun Hu ◽

Jinliang He

Keyword(s):

Electrical Properties ◽

Zno Varistor

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The effect of Bi2O3content on the microstructure and electrical properties of ZnO varistor materials

Journal of Applied Physics ◽

10.1063/1.343978 ◽

1989 ◽

Vol 66 (9) ◽

pp. 4317-4324 ◽

Cited By ~ 78

Author(s):

E. Olsson ◽

G. L. Dunlop

Keyword(s):

Electrical Properties ◽

Zno Varistor

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Microstructure and Electrical Properties of Low-Voltage Barium Titanate Doped Zinc Oxide Varistor Ceramics

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.d7326.118419 ◽

2019 ◽

Vol 8 (4) ◽

pp. 2713-2718

Keyword(s):

Zinc Oxide ◽

Electrical Properties ◽

Barium Titanate ◽

Grain Boundary ◽

Barrier Height ◽

Current Density ◽

Low Voltage ◽

X Ray ◽

Highly Nonlinear ◽

Zno Varistors

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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