High electromechanical performance with spark plasma sintering of undoped K0.5Na0.5NbO3 ceramics

Bah, Micka; Giovannelli, Fabien; Schoenstein, Frédéric; Feuillard, G.; Clézio, Emmanuel Le; Monot‐Laffez, Isabelle

doi:10.1016/j.ceramint.2013.12.097

Cited by 55 publications

(46 citation statements)

References 38 publications

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“…Mainly three factors account for the problem: First, a relatively low sintering temperature compared to other piezoelectric ceramics; second, a deviation from stoichiometry resulting in the formation of extra phases; and finally, the difficulty in obtaining a uniform microstructure during sintering [2,3,5]. In principle, the pressure sintering such as hotpress (HP) and spark-plasma sintering (SPS) [4][5][6] is effective to densify the bulk ceramics. However, such technique is not suitable to prepare the KNN ceramics in industrial manufacture, due to its low mass productivity and high cost.…”

Section: Introductionmentioning

confidence: 99%

Improvement of the piezoelectric and ferroelectric properties of (K, Na)0.5NbO3 ceramics via two-step calcination–milling route

Wang

Huan

et al. 2015

Ceramics International

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Section: Introductionmentioning

confidence: 99%

Improvement of the piezoelectric and ferroelectric properties of (K, Na)0.5NbO3 ceramics via two-step calcination–milling route

Wang

Huan

et al. 2015

Ceramics International

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“…After aging of one day to reach stable state, the complex electric impedances of the samples are measured, and compared to the ones obtained by simulation with KLM model. This procedure is described in a previous study [13,14] and allowed to deduce the electromechanical, dielectric and acoustic properties of the material (thickness mode). Table 1 summarizes the electromechanical, dielectric and acoustic properties of K 0.5 Na 0.5 NbO 3 of these different microstructures.…”

Section: Piezoelectric Characterizationmentioning

confidence: 99%

“…Later on, it has been also proposed that the effects of these dopants was to lower the Orthorhombic-Tetragonal transition temperature and influence the morphotropic phase boundary (MPB), resulting in properties enhancement [12]. In a recent study [13], it has been shown that an accurate control of the microstructure all along the synthesis and sintering processing allow to reach such high electromechanical coupling factors. Thus, the aim of this work is to determine the role of the microstructure engineering, for what concerns grain size and densification, on the piezoelectric properties of undoped KNN.…”

Section: Introductionmentioning

confidence: 99%

Piezoelectric performances of undoped (K,Na)NbO3 ceramics and crystals for transducers applications

Bah¹,

Giovannelli²,

Schoenstein³

et al. 2014

AIP Conference Proceedings

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“…In addition, tantalum presents interesting grain growth inhibitor properties [14]. Indeed, Bah et al have highlighted the impact of a fine and homogeneous grain size on pure KNN densification and properties [15].…”

Section: Introductionmentioning

confidence: 99%

Composite microstructures and piezoelectric properties in tantalum substituted lead-free K0.5Na0.5Nb1-xTaxO3 ceramics

Jean

Schoenstein

Zaghrioui

et al. 2018

Ceramics International

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K0.5Na0.5Nb1-xTaxO3 (KNNT) (with x = 0.00, 0.05, 0.10, 0.20, 0.30, 0.50 and 1) ceramics are prepared by ball milling and two calcinations at 830 °C for 5 hours. Subsequent sintering of centimeter size pellets, 1-2 mm thick, is studied using conventional and spark plasma sintering techniques with various conditions. X-Ray diffraction and Raman spectroscopy phase identification reveal orthorhombic to tetragonal phase transitions occurring at about x = 0.50, associated to chemical disorder. Scanning electron microscope observations and associated energy dispersive X-ray spectroscopy analysis reveal some composite aspect of the ceramics. Substitution of niobium by tantalum, corresponding to x increase, decreases significantly the grain size but also the densification of the ceramics sintered by conventional sintering, while, enhancement of the piezoelectric properties is observed for both sintering techniques.Thanks to parameters optimization of the spark plasma sintering process, temperature-time-pressure, significant improvement of the relative density over 96 %, is obtained for all the compositions sintered between 920 and 960 °C, under 50 MPa, for 5 to 10 minutes with heating rates of 100° C/min. High relative permittivity (εr = 1027), piezoelectric charge coefficient (d33 = 160 pC/N) and piezoelectric coupling factor (kp = 46 %) are obtained in spark plasma sintered K0.5Na0.5Nb1-xTaxO3 composite ceramics, for x ranging between 0.10 and 0.30 and for some specific spark plasma sintering conditions. Thus, tantalum single element substitution on niobium site, combined with spark plasma sintering, is revealed to be a powerful combination for the optimization and the reliability of piezoelectric properties in KNN system.

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High electromechanical performance with spark plasma sintering of undoped K0.5Na0.5NbO3 ceramics

Cited by 55 publications

References 38 publications

Improvement of the piezoelectric and ferroelectric properties of (K, Na)0.5NbO3 ceramics via two-step calcination–milling route

Improvement of the piezoelectric and ferroelectric properties of (K, Na)0.5NbO3 ceramics via two-step calcination–milling route

Piezoelectric performances of undoped (K,Na)NbO3 ceramics and crystals for transducers applications

Composite microstructures and piezoelectric properties in tantalum substituted lead-free K0.5Na0.5Nb1-xTaxO3 ceramics

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