Effect of Sintering Temperature on the Microstructural Evolution of ZnO Varistors

Cao, Wenbin; Guo, Yuwei; Su, Jinfeng; Liu, Jianke

doi:10.1007/s11664-022-10054-6

Cited by 7 publications

(3 citation statements)

References 38 publications

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“…With respect to low-temperature sintering of ZnO-based varistors, previous studies mainly focused on the incorporation of SiO 2 , [7,[10][11][12][13] Bi 2 O 3 , [14][15][16] and the formation of the Bi-Sb-O phase. [6,17] The impact of chromium oxide (Cr 2 O 3 ) dopants on the sintering temperature of ZnO-Bi 2 O 3 -based varistors has been rarely investigated.…”

Section: Methodsmentioning

confidence: 99%

“…The other approach is to reduce the sintering temperature of ZnO-based varistors to below 950 °C. [9,10] This low sintering temperature affords the reduction of palladium ratio in MLCV silver-palladium electrodes or direct utilization of pure silver inner electrodes (with a melting point of 961 °C). This strategy can not only mitigate reaction between the inner electrodes and the thick ceramic films but also diminish manufacturing costs.…”

Section: Introductionmentioning

confidence: 99%

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An Ultralow Concentration of Cr₂O₃ Dopants‐Driven Lower Temperature Sintering ZnO‐Based Varistor Ceramics

Cheng,

Zheng,

Zeng

et al. 2024

Physica Rapid Research Ltrs

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Low working voltage‐driven ZnO‐based varistor ceramics play an important role in the multilayer chip varistors, which require a low sintering temperature of ZnO varistor for its low energy consumption. Herein, a remarkable reduction of the sintering temperature from the usual 1100–1300 °C to 950 °C is successfully achieves in the ZnO ceramics via a certain 0.05 mol% of Cr2O3 dopants. The underlying mechanism is found to be involved with the formation of basal‐plane inversion boundaries between the ZnO grains, which can promote the rapid grain growth within the ceramics. Furthermore, the ZnO varistors with 0.05 mol% Cr2O3 dopant exhibit excellent performance. A low breakdown voltage of 416 V mm−1, a high nonlinear coefficient of 39, and a low leakage current of 3.4 μA are obtained simultaneously. This work presents an effective and promising approach for the cost‐efficient preparation of high‐performance ZnO‐based varistors, which have particular significance for the application of multilayer chip varistors with low working voltage.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Ultralow Concentration of Cr₂O₃ Dopants‐Driven Lower Temperature Sintering ZnO‐Based Varistor Ceramics

Cheng,

Zheng,

Zeng

et al. 2024

Physica Rapid Research Ltrs

View full text Add to dashboard Cite

show abstract

“…Figure 5 illustrates the crystal structure of α, β, and γ polymorphs of V 2 O 5 [135]. The type and content of the polymorphs of Bi2O3 in MOVs depend highly on the sintering temperature, dwell time, heating/cooling rate, and the composition of ZnO-Bi2O3based varistors [120,133]. The δ-and β-Bi2O3 phases are good ionic conductors, promoting the oxygen migration from the GBs, but the γ-and α-Bi2O3 phases are low ionic conductors.…”

Section: Polymorphisms Of Bi 2 O 3 and V 2 Omentioning

confidence: 99%

Effects of Dopants and Processing Parameters on the Properties of ZnO-V2O5-Based Varistors Prepared by Powder Metallurgy: A Review

Lungu¹

2023

Materials

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This article reviews the progress in developing ZnO-V2O5-based metal oxide varistors (MOVs) using powder metallurgy (PM) techniques. The aim is to create new, advanced ceramic materials for MOVs with comparable or superior functional properties to ZnO-Bi2O3 varistors using fewer dopants. The survey emphasizes the importance of a homogeneous microstructure and desirable varistor properties, such as high nonlinearity (α), low leakage current density (JL), high energy absorption capability, reduced power loss, and stability for reliable MOVs. This study investigates the effect of V2O5 and MO additives on the microstructure, electrical and dielectric properties, and aging behavior of ZnO-based varistors. The findings show that MOVs with 0.25–2 mol.% V2O5 and MO additives sintered in air over 800 °C contain a primary phase of ZnO with a hexagonal wurtzite structure and several secondary phases that impact the MOV performance. The MO additives, such as Bi2O3, In2O3, Sb2O3, transition element oxides, and rare earth oxides, act as ZnO grain growth inhibitors and enhance the density, microstructure homogeneity, and nonlinearity. Refinement of the microstructure of MOVs and consolidation under appropriate PM conditions improve their electrical properties (JL ≤ 0.2 mA/cm2, α of 22–153) and stability. The review recommends further developing and investigating large-sized MOVs from the ZnO-V2O5 systems using these techniques.

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Effects of radius and electronegativity of donors on the microstructure and mechanical, thermal, and electrical properties of ZnO varistors

Wang,

Lu,

Gao

et al. 2024

J Electroceram

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Effect of Sintering Temperature on the Microstructural Evolution of ZnO Varistors

Cited by 7 publications

References 38 publications

An Ultralow Concentration of Cr₂O₃ Dopants‐Driven Lower Temperature Sintering ZnO‐Based Varistor Ceramics

An Ultralow Concentration of Cr₂O₃ Dopants‐Driven Lower Temperature Sintering ZnO‐Based Varistor Ceramics

Effects of Dopants and Processing Parameters on the Properties of ZnO-V2O5-Based Varistors Prepared by Powder Metallurgy: A Review

Effects of radius and electronegativity of donors on the microstructure and mechanical, thermal, and electrical properties of ZnO varistors

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Effect of Sintering Temperature on the Microstructural Evolution of ZnO Varistors

Cited by 7 publications

References 38 publications

An Ultralow Concentration of Cr2O3 Dopants‐Driven Lower Temperature Sintering ZnO‐Based Varistor Ceramics

An Ultralow Concentration of Cr2O3 Dopants‐Driven Lower Temperature Sintering ZnO‐Based Varistor Ceramics

Effects of Dopants and Processing Parameters on the Properties of ZnO-V2O5-Based Varistors Prepared by Powder Metallurgy: A Review

Effects of radius and electronegativity of donors on the microstructure and mechanical, thermal, and electrical properties of ZnO varistors

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An Ultralow Concentration of Cr₂O₃ Dopants‐Driven Lower Temperature Sintering ZnO‐Based Varistor Ceramics

An Ultralow Concentration of Cr₂O₃ Dopants‐Driven Lower Temperature Sintering ZnO‐Based Varistor Ceramics