Phase transition, dielectric and piezoelectric properties of Li K1−NbO3

Doping effect on the lattice parameters, vibration modes, dielectric and piezoelectric properties of LiSbO3, LiTaO3 and LiNbO3 substituted lead-free K0.5Na0.5NbO3 (KNN) ceramics are investigated. All compositions are crystallized in morphotropic phase boundary region. Enhanced piezoelectric and electromechanical response d33 ~176–197 pC/N, kp ~45%–48%, and kt~34%–47% obtained in the doped ceramics are due to the presence of the polymorphic phase transition between orthorhombic and tetragonal phase at room temperature.

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Two-Step Sintering, Microstructure and Electrical Properties of (Ba, Ca)(Ti, Zr)O3 Lead-Free Ceramics

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.749.79 ◽

2015 ◽

Vol 749 ◽

pp. 79-83

Author(s):

Pornsuda Bomlai

Keyword(s):

Phase Transition ◽

Grain Size ◽

Electrical Properties ◽

Piezoelectric Properties ◽

Orthorhombic Phase ◽

Lead Free ◽

Lead Free Ceramics ◽

Average Grain Size ◽

Sintering Method ◽

Dielectric And Piezoelectric Properties

In this work, the (Ba1-xCax)(Ti1-yZry)O3 lead-free ceramics were prepared by the two-step sintering method, and effects of Ca and Zr contents on phase structure, densification, microstructure, and electrical properties were investigated. It was found that all samples showed orthorhombic phase. The highest density of 5.84 ± 0.01 g/cm3 was achieved in x = 0.05, y = 0.05 sample. The average grain size, phase transition temperature, dielectric and piezoelectric properties significantly decreased by introducing of the Ca/Zr content. The ceramics with a small amount of Ca and Zr maintain good piezoelectric properties, and a lower dielectric loss. The composition with x = 0.05, y = 0.025 demonstrated optimum electrical properties of d33 ∼211 pC/N, TC ∼ 119 °C, εr ∼ 1788, and tanδ ∼ 0.04.

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Phase Structure, Microstructure and Electrical Properties of Lead-Free (1-x) [Na0.515K0.485]0.94Li0.06(Nb0.99Ta0.01)O3 - BiAlO3 Ceramics

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.747.781 ◽

2013 ◽

Vol 747 ◽

pp. 781-784 ◽

Cited By ~ 1

Author(s):

Pornsuda Bomlai

Keyword(s):

Phase Transition ◽

Electrical Properties ◽

Phase Structure ◽

Piezoelectric Properties ◽

Perovskite Phase ◽

Lead Free ◽

Cubic Phase ◽

X Ray Diffraction ◽

Polymorphic Phase Transition ◽

Dielectric And Piezoelectric Properties

Lead-free (1-x)[(Na0.515K0.485)0.94Li0.06(Nb0.99Ta0.01)O3]-xBiAlO3 (NKLNT-BA; x = 0, 0.005, 0.010, 0.015, and 0.020) ceramics were fabricated by a conventional mixed-oxide method. The effects of BiAlO3 addition on the phase structure, microstructure and electrical properties of ceramic were then studied. The result indicated that grain size decreased with increasing of BiAlO3 content. In the composition range studied, the perovskite phase with the coexistence of the orthorhombic and tetragonal phases was identified at approximately x 0.005 by the X-ray diffraction analysis and dielectric spectroscopy, which led to a significant enhancement of the piezoelectric properties. The tetragonality increased with further increasing x. The temperature dependence of dielectric properties showed that the addition of BiAlO3 slightly decreased the ferroelectric tetragonal-paraelectric cubic phase transition temperature (TC), but greatly shifted the polymorphic phase transition from the ferroelectric orthorhombic to the ferroelectric tetragonal phase (TOT) to lower room temperature. The dielectric and piezoelectric properties are enhanced for the composition near the orthorhombic-tetragonal polymorphic phase boundary. The unmodified-(Na0.515K0.485)0.94Li0.06(Nb0.99Ta0.01)O3 ceramics exhibit optimum electrical properties (d33 = 225 pC/N and TC = 418°C).

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Phase transition, dielectric and piezoelectric properties of K0.5Na0.5NbO3–CaTi0.9Zr0.1O3 lead-free ceramics

Journal of Materials Science ◽

10.1007/s10853-011-5811-2 ◽

2011 ◽

Vol 47 (1) ◽

pp. 397-402 ◽

Cited By ~ 8

Author(s):

Dunmin Lin ◽

Kin Wing Kwok

Keyword(s):

Phase Transition ◽

Piezoelectric Properties ◽

Lead Free ◽

Lead Free Ceramics ◽

Dielectric And Piezoelectric Properties

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DIELECTRIC AND PIEZOELECTRIC PROPERTIES OF (K,Na)NbO3-BASED PIEZOELECTRIC CERAMICS

Journal of Advanced Dielectrics ◽

10.1142/s2010135x11000380 ◽

2011 ◽

Vol 01 (03) ◽

pp. 345-349 ◽

Cited By ~ 1

Author(s):

ERIC A. PATTERSON ◽

DAVID P. CANN

Keyword(s):

Phase Transition ◽

Solid State ◽

Room Temperature ◽

Single Phase ◽

Piezoelectric Properties ◽

Lead Free ◽

Maximum Strain ◽

X Ray Diffraction ◽

X Ray ◽

Dielectric And Piezoelectric Properties

Solid solutions based on Li , Ta and Sb -doped (K0.5Na0.5)NbO3 (KNN) lead-free perovskite systems were created using standard solid-state methods. X-ray diffraction was used to confirm that all compositions were single phase and to verify the phase transition from tetragonal to cubic at TC = 302° C . The three compositions examined, originally developed by Saito and Li , were shown to be strongly ferroelectric with sharp peaks in permittivity present at the Curie temperature. The optimum composition had loss tangent values below 5% up to 100 kHz at room temperature. Bipolar hysteresis measurements showed high values for both maximum polarization (25 and 21 μC/cm2) and remenant polarizations (20 and 16 μC/cm2) for undoped and 0.2 wt% CuO -doped samples. Maximum strain values of greater than 0.23% were observed.

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