Abstract
ZnO based varistor ceramics were prepared by a solid state reaction route, and the phase composition, microstructure and electrical properties were also investigated by XRD, SEM, a V–I source/measure unit and impedance spectroscopy. Results show that all the samples consist of mainly ZnO grains and secondary phases including Bi2O3, Zn7Sb2O12, Y2O3, Nd-rich and Y-containing Bi-rich phases. With the increase of sintering temperature, the number of grain boundaries and varistor voltage per grain boundary decreases, and the breakdown field (E1mA) decreases from 556.4 to 319.4 V/mm. The nonlinear coefficient value (α) is in the range of 60–70, the leakage current density values (JL) of all the varistor ceramics are <3 μA/cm2. Typically, the varistor ceramic sintered at 1,050 °C exhibits good electrical properties of E1mA = 556.4 V/mm, α = 61 and JL = 1.55 μA/cm2. Meanwhile, a schematic model for the electrical microstructure of ZnO based varistor is proposed with an equivalent circuit of Rg (RgbCgb) by impedance spectroscopy.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Journal of Materials Science: Materials in Electronics
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
