ZnO Varistor Defective Gd and Pr Ions

Abstract:

To the best of our knowledge the difference in the magnetic properties of ions like Gd (7.94 μB) and Pr (3.58 μB) on the electrical properties of ZnO-varistor have not been studied. To clarify this effect, the binary systems, ZnO-Gd₂O₃, ZnO-Pr₆O₁₁ and the ternary system ZnO-Gd₂O₃-Pr₆O₁₁ were studied. The ceramics were prepared according to the chemical formula; (100-X) mol% ZnO - (X) mol% Y, where X = 0.5, 1, 2, 3.5, 5, 6, 7.5, 9 and 15, Y is Gd₂O₃, Pr₆O₁₁ or Gd₂O_{3 +} Pr₆O₁₁. The samples have been sintered at 1200°C, 1250°C, 1300°C, 1350°C and 1400°C for 1 hr. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray (EDAX), (JxE), (CxV) and Electron Spin Resonance (ESR) have been studied and discussed. Utilizing J-E characteristics, the non-linearity coefficient (α), leakage current (Lg) and breakdown electric field (E_o) have been determined. In the present study, the effect of the magnetic properties on the non-linearity parameters was not clear and the non-linearity characteristics mainly depend upon the microstructure of the system. The ternary system (94%ZnO-4%Pr₆O₁₁- 2%Gd₂O₃) is superior to the binary systems, and can readily serve as a high-voltage varistor.

• Periodical: Defect and Diffusion Forum (Volume 332)
• Pages: 51-61
• DOI: https://doi.org/10.4028/www.scientific.net/DDF.332.51
• Online since: December 2012
• Authors: M. El-Hofy, A. El-Taabl, A.M. Abdel Aziz, M. Elkhatib
• Keywords: Gd₂O₃, Grain Boundary Parameters, J-E Characteristics, Microstructure, Pr₆O₁₁, Zinc Oxide (ZnO)

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