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Effect of sintering on grain boundary microstructure and electrical properties of CaCu3Ti4O12 ceramics

  • Material Science
  • Published:
Wuhan University Journal of Natural Sciences

Abstract

CaCu3Ti4O12 ceramic with a giant dielectric constant was synthesized by sol-gel method and sintered in three different sintering conditions: 1 035 °C for 48 h, 1 080 °C for 3 h and 48 h. The phase of the ceramics, the element distribution, the valance state of Ti ions at grain boundaries, and the electrical properties were characterized via X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), X-ray photoelectron spectroscopy (XPS), electrical conduction and dielectric measurement. The results demonstrate that the grain-boundary microstructure and the electrical properties are influenced by sintering conditions: ➀ By raising sintering temperature, the Cu-rich and Ti-poor grain boundary was formed and grain resistivity was decreased. ➁ By prolonging sintering time, the content of Ti3+ near the grain boundary increased, leading to the decrease of the grain-boundary resistivity and the increase of the activation energy at grain boundary. The ceramic, sintering at 1 080 °C for 48 h, exhibited a small grain resistivity (60.5 Ω · cm), a large grain-boundary activation energy (0.42 eV), and a significantly enhanced dielectric constant (close to 1×105 at a low frequency of 1×103 Hz ). The results of electrical properties accord with the internal boundary layer capacitor model for explaining the giant dielectric constant observed in CaCu3Ti4O12 ceramics.

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Authors and Affiliations

  1. City College, Wuhan University of Science and Technology, Wuhan, 430083, Hubei, China

    Zhi Yang

  2. School of Physics and Technology / Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan, 430072, Hubei, China

    Rui Xiong

Authors
  1. Zhi Yang
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  2. Rui Xiong
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Correspondence to Rui Xiong.

Additional information

Foundation item: Supported by the National Natural Science Foundation of China (51172166) and the Ph.D. Programs Foundation of City College, Wuhan University of Science and Technology (2014CYBSKY003)

Biography: YANG Zhi, female, Lecturer, Ph. D., research direction: ceramics with a giant dielectric constant.

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Yang, Z., Xiong, R. Effect of sintering on grain boundary microstructure and electrical properties of CaCu3Ti4O12 ceramics. Wuhan Univ. J. Nat. Sci. 20, 255–261 (2015). https://doi.org/10.1007/s11859-015-1090-0

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  • DOI: https://doi.org/10.1007/s11859-015-1090-0

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