• ZHI-JUN XU

Articles written in Bulletin of Materials Science

• Bi$_2$O$_3$-doped SnO$_2$ varistors with low breakdown electric fields

This work presents Bi$_2$O$_3$-doped SnO$_2$ ceramic varistors prepared through conventional ceramic processing in the sintering temperature range of 1290–1320$^{\circ}$C. The sample sintered at 1300$^{\circ}$C exhibits a breakdown electric field as low as 11.6 V mm$^{−1}$. Scanning electron microscopy images reveal that all the samples have a compact structure, andenergy dispersive spectroscopy results for the sample sintered at 1300$^{\circ}$C indicate that Bi distributes homogeneously along the grain boundaries and aggregates inhomogeneously on the grain surfaces. With increasing sintering temperature, the grain boundary barrier height remains nearly constant at 0.80 eV. In both the dielectric loss and electric modulus spectra of the sample sintered at 1300$^{\circ}$C, obvious relaxations were observed and the activation energies obtained from the respectivespectra were 0.33 and 0.15 eV, which are expected to be related to oxygen vacancies and interstitial ions, respectively. Complex impedance spectra are employed to develop a non-typical equivalent circuit model for the Bi$_2$O$_3$-doped SnO$_2$ ceramic varistors at low voltage that yields an excellent fit to the data.

• # Bulletin of Materials Science

Volume 43, 2020
All articles
Continuous Article Publishing mode

• # Dr Shanti Swarup Bhatnagar for Science and Technology

Posted on October 12, 2020

Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020