Article: Effect of sealed sintering on properties of Al doped ZnO varistor ceramics with high voltage gradient and low residual voltage Journal: International Journal of Microstructure and Materials Properties (IJMMP) 2025 Vol.18 No.4 pp.225 - 236 Abstract: Zinc oxide varistor have excellent nonlinear voltmeter characteristics and are the core components of key equipment for overvoltage protection in power systems. This study delves into how sealed sintering affects the electrical properties of Al-doped ZnO varistor ceramics. By comparing two formulas (a traditional one and an optimised low-residual-voltage one with higher Al and Bi2O3 content) across different sintering environments (open vs. sealed) and temperatures, significant findings were obtained. Under sealed sintering, the optimised formula achieved a 15% lower residual voltage ratio than the traditional formula. Notably, samples sintered at 1,150°C showed optimal performance: a residual voltage ratio(K) of 1.39, leakage current of 1.38 μA, and voltage gradient of 285.5 V/mm. Mechanistically, Al doping reduced grain resistivity and residual voltage, while added Bi, Ni, and Co elements increased the grain-boundary surface state density, suppressing leakage current. These outcomes are highly significant for enhancing the overvoltage protection capabilities of power systems. Inderscience Publishers - linking academia, business and industry through research

Title: Effect of sealed sintering on properties of Al doped ZnO varistor ceramics with high voltage gradient and low residual voltage

Authors: Xiao Lei; Xin Ning; Peng Liu; Jingke Guo; Yin Yue; Pengfei Meng

Addresses: State Grid Sichuan Electric Power Co., Ltd., Electric Power Research Institute, Chengdu. 610041, China ' State Grid Sichuan Electric Power Co., Ltd., Electric Power Research Institute, Chengdu. 610041, China ' State Grid Sichuan Electric Power Co., Ltd., Electric Power Research Institute, Chengdu. 610041, China ' Sichuan University, Chengdu. 610065, China ' Sichuan University, Chengdu. 610065, China ' Sichuan University, Chengdu. 610065, China

Abstract: Zinc oxide varistor have excellent nonlinear voltmeter characteristics and are the core components of key equipment for overvoltage protection in power systems. This study delves into how sealed sintering affects the electrical properties of Al-doped ZnO varistor ceramics. By comparing two formulas (a traditional one and an optimised low-residual-voltage one with higher Al and Bi₂O₃ content) across different sintering environments (open vs. sealed) and temperatures, significant findings were obtained. Under sealed sintering, the optimised formula achieved a 15% lower residual voltage ratio than the traditional formula. Notably, samples sintered at 1,150°C showed optimal performance: a residual voltage ratio(K) of 1.39, leakage current of 1.38 μA, and voltage gradient of 285.5 V/mm. Mechanistically, Al doping reduced grain resistivity and residual voltage, while added Bi, Ni, and Co elements increased the grain-boundary surface state density, suppressing leakage current. These outcomes are highly significant for enhancing the overvoltage protection capabilities of power systems.

Keywords: sealed sintering; ZnO varistor; microstructure; electrical performance.

DOI: 10.1504/IJMMP.2025.155448

International Journal of Microstructure and Materials Properties, 2025 Vol.18 No.4, pp.225 - 236

Received: 31 Jan 2025
Accepted: 23 Jul 2025
Published online: 03 Aug 2026 *

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Title: Effect of sealed sintering on properties of Al doped ZnO varistor ceramics with high voltage gradient and low residual voltage

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