Elsevier

Materials Letters

Volume 265, 15 April 2020, 127298
Materials Letters

The influence of sintering temperature on the microstructures and electrical performances of BCZT ceramics

https://doi.org/10.1016/j.matlet.2020.127298Get rights and content

Highlights

  • The phase composition of the BCZT ceramics was calibrated by the Rietveld refined XRD technique.

  • Increasing sintering temperature can enhance the ions displacement polarization and improve ε value.

  • The phenomenon of grain size reduction after 1330 °C sintering of samples was explained.

  • The growth mechanism of grain size was explained by the dynamic equation of grain growth.

Abstract

The effects of sintering temperature (1230–1330 °C) on phase composition, microstructure and electrical performance of (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 samples prepared by sol-gel method were investigated. Increasing sintering temperature could enhance the tetragonal distortion and improve electrical properties. The optimal sintering temperature is 1300 °C, and the mechanism of sintering temperature on grain size was explained by the oxygen vacancy theory and the dynamic growth theory of crystal.

Introduction

BaTiO3 and its solid solution have been a significant subject due to their excellent physicochemical properties [1], [2]. Some literatures point out that various oxides or titanates are usually introduced into BaTiO3 based ceramics to improve electrical performances. (Ba0.85Ca0.15) (Zr0.1Ti0.9)O3 (abbreviated as BCZT) ceramics synthesized by Ren show ultra-high piezoelectric properties [3]. Therefore, BCZT ceramics are considered one of the most valuable lead-free piezoelectric ceramics. The performance of BCZT ceramics depend not only on the ratio of Ca2+ or Zr4+, but also on their microstructures which are easily affected by sintering temperature [4], [5]. Consequently, it is necessary to study the influence mechanism of sintering temperature on the microstructure and electrical properties of BCZT ceramics [6]. BCZT powder was prepared by the liquid phase method due to the characteristics of reducing the sintering temperature [7].

In this study, the BCZT samples were synthetized via sol-gel technical. The influence of sintering temperature (1230–1330 °C) on the phase composition, surface morphology and electrical properties was investigated. The variation of grain size with sintering temperature was explained by the dynamic growth theory of crystals. The effect of the microstructure on the electrical properties of BCZT ceramics was discussed in detail.

Section snippets

Experimental

The (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCZT) samples were prepared by sol-gel technical. The main metal ions were provided by reagent grade of barium acetate, calcium nitrate, zirconium nitrate and butyl titanate provide. The sintering temperature was set at 1230–1330 °C for 2 h, which was derived from TG-DTA result for BCZT ceramics. Clear sol gel process descriptions have been mentioned in published work [8]. The phase composition of the samples was observed using X-ray diffraction and analyzed by

Results and discussions

The X-ray diffraction results of BCZT samples sintered at 1230–1330 °C are shown in Fig. 1. From Fig. 1(a), the samples all exhibit perovskite structure. Scientific research has found that the intensity ratio of (0 0 2) diffraction peak to (2 0 0) is 1:2, which indicates that the phase structure is tetragonal [9], [10]. From Fig. 1(b), the intensity ratio of (0 0 2) diffraction peaks to (2 0 0) are significantly less than 1:2, which indicates that the phase composition of the sample

Conclusions

The effect of sintering temperature on grain size was explained by oxygen vacancy theory and the dynamic growth theory of crystal. Increasing sintering temperature can enhance the ions displacement polarization and improve ε value. Rietveld refinement XRD spectra showed that BCZT ceramics are multiphase at room temperature, which is beneficial to the enhancement of piezoelectric properties. The decreased grain size of samples sintered at 1330 °C is attributed to the diffusion and fusion of

CRediT authorship contribution statement

Wenshuo Kang: Conceptualization, Data curation, Writing - original draft, Writing - review & editing, Software. Zhanshen Zheng: Funding acquisition, Resources, Supervision, Project administration. Yuanliang Li: Data curation, Investigation, Supervision. Rujie Zhao: Formal analysis, Investigation, Software.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This work was supported by Science and Technology Support Project of Hebei Province, China (Grant No. 15211111), and the National Natural Science Foundation of China (Grant No. 51502075).

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