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Microstructural developments and electrical properties of novel coarse-grained SnO2 varistors obtained by CuO addition for low-voltage applications

Maleki Shahraki, M ; Sharif University of Technology | 2018

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  1. Type of Document: Article
  2. DOI: 10.1016/j.ceramint.2018.07.067
  3. Publisher: Elsevier Ltd , 2018
  4. Abstract:
  5. This research focused on making novel low-voltage SnO2 varistors by CuO addition on conventional high-voltage SnO2 varistors. Moreover, the withstand surge capability of samples was studied. The results showed that CuO addition enhances grain growth of SnO2 and coarse-grained SnO2 varistors with simple microstructures were acquired in 1 mol% CuO-doped sample. This coarse-grained SnO2 varistor presented a high nonlinear coefficient (23) and low leakage current density (23 µA/cm2) with low breakdown field value of 0.6 kV/cm. Despite the large grain size, the low residual voltage ratio (2.3) was obtained for this sample compared to the CuO-free sample. The decrease in grain electric resistivity by CuO addition is responsible for the low residual voltage ratio observed in coarse-grained SnO2 varistors. Furthermore, it was found that withstanding surge current density and disruptive discharge current density of 1 mol% CuO-doped sample were 1.2 kA/cm2 and 1.4 kA/cm2, respectively, which is superior for low-voltage applications. © 2018 Elsevier Ltd and Techna Group S.r.l
  6. Keywords:
  7. CuO addition ; Low-voltage ; SnO2 ; Surge capability ; Varistor ; Copper oxides ; Current density ; Grain growth ; Leakage currents ; Disruptive discharges ; Low voltages ; Low-leakage current ; Low-voltage applications ; Microstructural development ; Varistors
  8. Source: Ceramics International ; Volume 44, Issue 15 , 2018 , Pages 18478-18483 ; 02728842 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/pii/S0272884218317978