Lead-Free KNN-Based Piezoelectric Materials

Safari, A.; Hejazi, Mehdi

doi:10.1007/978-1-4419-9598-8_5

Cited by 13 publications

(12 citation statements)

References 125 publications

(163 reference statements)

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“…However, the environmental and human health concerns due to the toxicity of lead forced the researchers to look for non-hazardous alternatives [1]. The most widely studied lead-free piezoceramics are based on the perovskite systems K 0.5 Na 0.5 NbO 3 (KNN) [2], (Na 1/2 Bi 1/2 )TiO 3 (NBT), BiFeO 3 [3], and (Ba,Ca)(Zr,Ti)O 3 (BCZT) [4,5]. The solid solution of Ba(Zr 0.2 Ti 0.8 )O 3 -(Ba 0.7 Ca 0.3 )TiO 3 was presented by Liu and Ren [6] as a pseudobinary ferroelectric system with a morphotropic phase boundary (MPB) and exceptionally-high electromechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Electromechanical properties of Ce-doped (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 lead-free piezoceramics

et al. 2019

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Lead-free piezoceramics based on the (Ba,Ca)(Zr,Ti)O 3 (BCZT) system exhibit excellent electromechanical properties for low-temperature actuation applications, but suffer from relatively high processing temperatures. Here we demonstrate an approach for the reduction of the sintering temperature and simultaneous increase of the electromechanical strain response of (Ba,Ca)(Zr,Ti)O 3 piezoceramics by aliovalent doping with Ce. The samples were prepared by solid state synthesis and their crystallographic structure, dielectric, ferroelectric, and electromechanical properties were investigated. The highest d * 33 value of 1189 pm/V was obtained for the sample with 0.05 mol% Ce, substituted on the A-site of the perovskite lattice. The results indicate a large potential of these materials for off-resonance piezoelectric actuators.

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Section: Introductionmentioning

confidence: 99%

Electromechanical properties of Ce-doped (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 lead-free piezoceramics

et al. 2019

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“…It was found that the functional properties of KNN solid solution were affected by the Na/K ratio, with MPB being formed by two adjacent orthorhombic ferroelectric phases, however, the properties are not markedly improved at MPB region [278]. One of the main obstacles in the development of KNN-based ceramics is the difficulty to achieve dense ceramics because of the evaporation of the alkali components at high temperature.…”

Section: Loss Behavior Of Selected Ferroelectricsmentioning

confidence: 99%

Losses in ferroelectric materials

Liu

Zhang

Jiang

et al. 2015

Materials Science and Engineering: R: Reports

265

112

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Ferroelectric materials are the best dielectric and piezoelectric materials known today. Since the discovery of barium titanate in the 1940s, lead zirconate titanate ceramics in the 1950s and relaxor-PT single crystals (such as lead magnesium niobate-lead titanate and lead zinc niobate-lead titanate) in the 1980s and 1990s, perovskite ferroelectric materials have been the dominating piezoelectric materials for electromechanical devices, and are widely used in sensors, actuators and ultrasonic transducers. Energy losses (or energy dissipation) in ferroelectrics are one of the most critical issues for high power devices, such as therapeutic ultrasonic transducers, large displacement actuators, SONAR projectors, and high frequency medical imaging transducers. The losses of ferroelectric materials have three distinct types, i.e., elastic, piezoelectric and dielectric losses. People have been investigating the mechanisms of these losses and are trying hard to control and minimize them so as to reduce performance degradation in electromechanical devices. There are impressive progresses made in the past several decades on this topic, but some confusions still exist. Therefore, a systematic review to define related concepts and clear up confusions is urgently in need. With this objective in mind, we provide here a comprehensive review on the energy losses in ferroelectrics, including related mechanisms, characterization techniques and collections of published data on many ferroelectric materials to provide a useful resource for interested scientists and engineers to design electromechanical devices and to gain a global perspective on the complex physical phenomena involved. More importantly, based on the analysis of available information, we proposed a general theoretical model to describe the inherent relationships among elastic, dielectric, piezoelectric and mechanical losses. For multi-domain ferroelectric single crystals and ceramics, intrinsic and extrinsic energy loss mechanisms are discussed in terms of compositions, crystal structures, temperature, domain configurations, domain sizes and grain boundaries. The intrinsic and extrinsic contributions to the total energy dissipation are quantified. In domain engineered ferroelectric single crystals and ceramics, polarization rotations, domain wall motions and mechanical wave scatterings at grain boundaries are believed to control the mechanical quality factors of piezoelectric resonators. We show that a thorough understanding on the kinetic processes is critical in analyzing energy loss behavior and other time-dependent properties in ferroelectric materials. At the end of the review, existing challenges in the study and control of losses in ferroelectric materials are analyzed, and future perspective in resolving these issues is discussed.

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“…The sample sintered by the conventional method has greater permittivity without dispersion, while the values of the dielectric constant of the samples sintered by microwaves have very low permittivity values at frequencies from 0 to 10 MHz. The porosity observed in the microstructure of the microwave-sintered piezoelectric materials affects the density of the material, and these defects cause a decrease in the dielectric values [37,38].…”

Section: Sintering Of K05na05nbo3 Powdersmentioning

confidence: 99%

Effect of Synthesis and Sintering Temperatures on K0.5Na0.5NbO3 Lead-Free Piezoelectric Ceramics By Microwave Heating

Lagunas¹,

Navarro-Rojero²,

Salvador

et al. 2021

Preprint

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Powders of K0.5Na0.5NbO3 lead-free piezoelectric ceramics were successfully synthesized via conventional and microwave-assisted heating. A single-mode microwave equipment was used to perform the synthesis following the mixed oxide route and then sintering at different temperatures. The synthesized powders obtained and then sintered by microwave and conventional methods were evaluated by thermogravimetry analysis, X-ray diffraction (XRD), and field emission scanning electron microscopy. Microwave synthesis processing for 10 minutes at 650 ºC using a heating rate of 30 ºC/min promotes the formation of 2 K0.5Na0.5NbO3 nanoparticles. Perovskite structure formed during calcination shows the coexistence of tetragonal-orthorhombic geometry according to XRD patterns. The microwave-obtained particles are consistent with the theoretical stoichiometry. Particle size increases as the reaction temperature is increased from 650 ºC to 800 ºC. An intermediate phase (K,Na)2Nb4O11 is formed in the entire range of synthesis temperatures studied. The samples obtained by microwave sintering show a structure similar to the samples sintered by the conventional method. However, the porosity observed in the microstructure of the microwave-sintered piezoelectric materials affects the density of the material, and these defects cause a decrease in the dielectric values.

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Lead-Free KNN-Based Piezoelectric Materials

Cited by 13 publications

References 125 publications

Electromechanical properties of Ce-doped (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 lead-free piezoceramics

Electromechanical properties of Ce-doped (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 lead-free piezoceramics

Losses in ferroelectric materials

Effect of Synthesis and Sintering Temperatures on K0.5Na0.5NbO3 Lead-Free Piezoelectric Ceramics By Microwave Heating

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Lead-Free KNN-Based Piezoelectric Materials

Cited by 13 publications

References 125 publications

Electromechanical properties of Ce-doped (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 lead-free piezoceramics

Electromechanical properties of Ce-doped (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 lead-free piezoceramics

Losses in ferroelectric materials

Effect of Synthesis and Sintering Temperatures on K0.5Na0.5NbO3&nbsp;Lead-Free Piezoelectric Ceramics By Microwave Heating

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Effect of Synthesis and Sintering Temperatures on K0.5Na0.5NbO3 Lead-Free Piezoelectric Ceramics By Microwave Heating