Sinterability and Dielectric Properties of LiTaO3-Based Ceramics with Addition of CoO.

Youfeng Zhang,Shasha He,Yali Yao

doi:10.3390/ma13071506

Youfeng Zhang, Shasha He + Show 1 more

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https://doi.org/10.3390/ma13071506

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Journal: Materials	Publication Date: Mar 25, 2020
Citations: 3	License type: CC BY 4.0

Affiliation: Shanghai University of Engineering Science

Abstract

Lithium tantalite (LiTaO3) is a common piezoelectric and ferroelectric crystal, but the LiTaO3 polycrystalline ceramics have rarely been reported, and their refractory character presents difficulties in their fabrication. In this study, LiTaO3-based ceramics with different amounts of CoO were prepared by pressureless sintering at 1250 °C, and the effects of the amount of sintering aid on the sinterability, microstructure, and dielectric properties of the ceramics were investigated. The relative densities of the LiTaO3-based ceramics were significantly improved by the addition of CoO powder. The LiTaO3-based ceramics achieved the highest relative density (89.4%) and obtained a well-grained microstructure when the added amount of CoO was 5 wt.%. Only the LiTaO3 phase in the ceramics was observed, indicating that the ions Co diffused into the LiTaO3 lattices and mainly existed in two forms: Co2+ and Co3+. The effects of the added amount of CoO on the dielectric properties of the LiTaO3-based ceramics were studied thoroughly. Consequently, the dielectric constant was enhanced, and the dielectric loss decreased in the LiTaO3-based ceramics with the addition of CoO. The optimal value was obtained at 5 wt.% of CoO-added LiTaO3-based ceramics.

Highlights

Lithium tantalite (LiTaO3 ), an excellent single crystal, has high planar electromechanical coupling, a mechanical quality factor, and low acoustic transmission loss and is used in various applications because of its low dielectric constant [1,2,3,4]
Relatively little attention has been paid to the fabrication and sintering of LiTaO3 ceramics or their microstructures and properties, because LiTaO3 is beset with difficulties regarding densification in the sintering process [9,10,11,12,13]
Previous studies have tried to facilitate the sintering of the LiTaO3 ceramics by adding oxides/fluorides or by doping with two steps of powder synthesis first, followed by sintering [14,15]

Summary

Introduction

Lithium tantalite (LiTaO3 ), an excellent single crystal, has high planar electromechanical coupling, a mechanical quality factor, and low acoustic transmission loss and is used in various applications because of its low dielectric constant [1,2,3,4]. Relatively little attention has been paid to the fabrication and sintering of LiTaO3 ceramics or their microstructures and properties, because LiTaO3 is beset with difficulties regarding densification in the sintering process [9,10,11,12,13]. Previous studies have tried to facilitate the sintering of the LiTaO3 ceramics by adding oxides/fluorides or by doping with two steps of powder synthesis first, followed by sintering [14,15]. LiTaO3 -based ceramics through a pressureless sintering process using raw CoO and LiTaO3 powders. The LiTaO3 -based ceramics were successfully fabricated by adding different amounts of CoO. The effects of the different components on the sinterability and dielectric properties of the LiTaO3 -based ceramics were studied

Experimental Details

Results and Discussion

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Conclusion