Optimization of Bi₂O₃, TiO₂, and Sb₂O₃Doped ZnO-Based Low-Voltage Varistor Ceramic to Maximize Nonlinear Electrical Properties

Abstract

In ZnO-based low voltage varistor, the two essential features of microstructure determining its nonlinear response are the formation Bi-enriched active grain boundaries as well as a controlled ZnO grain size by secondary spinel-type phases. Besides, the microstructure and phase composition are strongly affected by the dopant concentration during sintering process. In this study, the optimal dopant levels of Bi2O3, TiO2, and Sb2O3 to achieve maximized nonlinear electrical property (alpha) were quantified by the response surface methodology (RSM). RSM was also used to understand the significance and interaction of the factors affecting the response. Variables were determined as the molar ratio of Bi2O3, TiO2, and Sb2O3. The alpha was chosen as response in the study. The 5-level-3-factor central composite design, with 20 runs, was used to conduct the experiments by ball milling method. A quadratic model was established as a functional relationship between three independent variables and alpha. According to the results, the optimum values of Bi2O3, TiO2, and Sb2O3 were obtained 0.52, 0.50, and 0.30, respectively. Under optimal conditions the predicted alpha (9.47) was calculated using optimal coded values from the model and the theoretical value is in good agreement with the value (9.43) obtained by confirmation experiment.

New Technical Parameters and Operational Improvements of the Metal Oxide Varistors Manufacturing Process

“…But, as an order of magnitude, they are identical. In the first phase, an increase with a low temperature gradient (for 10 h), up to 400 • C, is performed, maintaining a constant temperature for 3 h. At this stage, any traces of waste water are removed [11].…”

Effects of sizes of additive particles on suspensions, microstructures, and electrical properties of ZnO varistors

“…ZnO varistors have been widely used as lightning arresters or transient overvoltage protectors in power transmission and circuits due to their excellent electrical properties, such as high nonlinear coefficient, high‐energy absorption capability, small leakage current, etc . ZnO‐based varistors mainly contain ZnO powder as the main component (typically ≥90%) with small amount of oxide additives, such as Bi 2 O 3 , Co 2 O 3 , MnO 2 , Sb 2 O 3 , NiO, etc . In the raw materials used in the production of the ZnO varistors, the size of the main material ZnO is micro‐nano level (200‐800 nm), while most of the additive oxides are relatively larger, and the particle size distribution of each additive oxide is quite different, which is not conducive to the uniform distribution of the raw materials in the preparation process.…”

Enhancement of electronic protection to reduce e-waste

“…Currently, the protection as a preventive action is carried out by a voltagelimiting device such as varistor which is associated in parallel of electronics into the electrical circuit. It means the varistor has presented high resistance ohmic behavior within the operating normal voltage that the normal electrical current never flows through the associated varistors [16]. On the other hand, the varistor changes into non-ohmic behavior at the overvoltage and allows the current to flow through itself.…”

“…However, RSM involves the complicated statistical calculation of fitting process as well as the regression analysis while ANNs are free of the mathematic functionalization [16,42,45,46]. ANNs have been successfully used for modeling of productive processes such as photodegradation of many environmental organic pollutants including ethylene-diamine-tetra-acetic acid [47], nitrogen oxides [48], nitrilotriacetic acid [49], C.I.…”