Evaluating the polymorphic phase transition in calcium-doped Ba(Zr0.05Ti0.95)O3: a lead-free piezoelectric ceramic

Structural and dielectric investigations were carried out on a perovskite lead-free (Ba1−xCax)(Zr0.05Ti0.95)O3ferroelectric ceramic forx= 0.03, 0.05, 0.08, 0.10, 0.12 and 0.15. The room-temperature structural analysis reveals a crossover from orthorhombic to tetragonal crystal structure nearx= 0.10. A coexistence of tetragonal (P4mm) and orthorhombic (Pmm2) structure is observed in the composition range 0.05 ≤x≤ 0.10. The fraction of tetragonal phase increases from 27% forx= 0.05 to 71% forx= 0.10. The dielectric measurements show that the tetragonal to orthorhombic and rhombohedral to orthorhombic transition temperatures decrease with an increase in Ca2+content, while the cubic to tetragonal transition temperature remains the same. It is also shown that for the tetragonal to orthorhombic transition a phase coexistence occurs over a temperature range of about 18 K. The coexistence range covers room temperature for intermediate compositions:x= 0.05, 0.08 and 0.10. Therefore, higher dielectric and piezoelectric properties are observed in these compositions.

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Effect of Doping Ions on Structure and Electrical Properties of Lead-Free KNN Ceramics

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1058.190 ◽

2014 ◽

Vol 1058 ◽

pp. 190-195

Author(s):

Na Yin ◽

Abolfazl Jalalian ◽

Zhi Gang Gai ◽

Lan Ling Zhao ◽

Xiao Lin Wang

Keyword(s):

Phase Transition ◽

Electrical Properties ◽

Tetragonal Phase ◽

Room Temperature ◽

Piezoelectric Properties ◽

Boundary Region ◽

Lead Free ◽

Vibration Modes ◽

Polymorphic Phase Transition ◽

Dielectric And Piezoelectric Properties

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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Dielectric and Piezoelectric Properties of (Na,Ba)(Nb,Ti)O3 Lead-Free Piezoelectric Ceramics

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.445.55 ◽

2010 ◽

Vol 445 ◽

pp. 55-58 ◽

Cited By ~ 4

Author(s):

Rintaro Aoyagi ◽

Makoto Iwata ◽

Masaki Maeda

Keyword(s):

Crystal Structure ◽

Solid Solution ◽

Dielectric Properties ◽

Room Temperature ◽

Electromechanical Coupling ◽

Piezoelectric Properties ◽

Electromechanical Coupling Factor ◽

Coupling Factor ◽

Lead Free ◽

Dielectric And Piezoelectric Properties

(Na1-xBax)(Nb1-xTix)O3 (NNBTx; x=0.0-0.21) solid-solution ceramics were synthesized and their crystal structure, dielectric properties and piezoelectric properties were investigated. The crystal structure at room temperature of NNBTx varied from orthorhombic to tetragonal with increasing BaTiO3 content x. The phase boundary between orthorhombic and tetragonal at room temperature was confirmed BT content between x=0.08 and 0.09. For x>0.05, it was found that the Curie temperature was decreased with increasing x. The highest electromechanical coupling factor, kp, and the largest piezoelectric constant, d33, were obtained at x=0.09-0.10.

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Investigation of the Morphotropic Phase Boundary (MPB) of (1-x-y)BaZrO3-x(K0.45Na0.5Li0.05)NbO3-yBi (Mg0.5Ti0.5)O3

Materials Science Forum ◽

10.4028/www.scientific.net/msf.787.242 ◽

2014 ◽

Vol 787 ◽

pp. 242-246

Author(s):

Rui Lin Wu ◽

Tomoaki Karaki ◽

Jiang Tao Zeng ◽

Liao Ying Zheng ◽

Wei Ruan ◽

...

Keyword(s):

Phase Boundary ◽

Morphotropic Phase Boundary ◽

Tetragonal Phase ◽

Room Temperature ◽

Piezoelectric Properties ◽

Piezoelectric Ceramics ◽

Solid State Reaction Method ◽

Lead Free ◽

Reaction Method ◽

Dielectric And Piezoelectric Properties

Lead-based piezoelectric ceramics have excellent piezoelectric properties with the compositions near the rhombohedral-tetragonal morphotropic phase boundary (MPB)[1,2]. In these materials, the dielectric and piezoelectric properties show the maximal values at MPB. For lead-free piezoelectric ceramics, finding the MPB area is a promising way to improve their properties. In this paper, the (1-x-y)BaZrO3-x(K0.45Na0.5Li0.05)NbO3-yBi (Mg0.5Ti0.5)O3 lead-free piezoelectric ceramics were prepared by solid-state reaction method, and their piezoelectric properties and dielectric properties were investigated. With the increase of KNLN content, the crystal structure changed from rombohedral phase to tetragonal phase, thus existed a MPB[3,4] between rombohedral and tetragonal phase. At room temperature, the specimen with the composition at MPB (x=0.93, y=0.01) shows the optimal piezoelectric properties (d33=225pC/N and kp=45%), which indicates that this material is a potential lead-free piezoceramic.

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Structure, dielectric, and piezoelectric properties of K0.5Na0.5NbO3-based lead-free ceramics

RSC Advances ◽

10.1039/c8ra04038a ◽

2018 ◽

Vol 8 (43) ◽

pp. 24286-24296 ◽

Cited By ~ 15

Author(s):

Sushmita Dwivedi ◽

Tanvi Pareek ◽

Sunil Kumar

Keyword(s):

Room Temperature ◽

Piezoelectric Properties ◽

Lead Free ◽

X Ray Diffraction ◽

X Ray ◽

System P ◽

Lead Free Ceramics ◽

Diffraction Patterns ◽

Dielectric And Piezoelectric Properties

Room temperature powder X-ray diffraction patterns of (1 – x)K0.5Na0.5NbO3–xBi(Zn0.5Ti0.5)O3 system.

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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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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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Microstructure and Piezoelectric Properties of [(K0.5Na0.5)1-xLix](Nb1-yTay)O3 Lead-Free Piezoelectric Ceramics

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.156-157.1522 ◽

2010 ◽

Vol 156-157 ◽

pp. 1522-1527

Author(s):

Bei Xu ◽

Feng Gao ◽

Bo Li ◽

Liang Liang Liu ◽

Zhen Qi Deng

Keyword(s):

Room Temperature ◽

Composition Range ◽

Piezoelectric Properties ◽

Piezoelectric Ceramics ◽

Mechanical Quality Factor ◽

Lead Free ◽

Mechanical Quality ◽

Curie Temperature Tc ◽

Room Temperature Dielectric Constant ◽

Tetragonal Phase Transition

Li+ and Ta5+ modified lead-free piezoelectric ceramics [(K0.5Na0.5)1-xLix](Nb1-yTay)O3 have been prepared by an ordinary sintering technique. Effect of Li+ and Ta5+ on microstructure and piezoelectric properties of the ceramics was systematically studied. A morphotropic phase boundary between orthorhombic and tetragonal phases is identified in the composition range of (0.02≤x≤0.04, 0.15≤y≤0.25), which can enhance electrical properties of [(K0.5Na0.5)1-xLix](Nb1-yTay)O3 ceramics. The Curie temperature TC of these ceramics is lower than that of pure (K0.5Na0.5)NbO3 ceramics, but the temperature of orthorhombic to tetragonal phase transition TO-T of the former is higher than that of the latter. TC and TO-T both decrease as the content of Ta5+ increases. With the addition of Li+ increasing, TC increases. The optimal piezoelectric properties are obtained at (x, y)=(0.03, 0.20): piezoelectric constant d33 is 192pC/N; the electromechanical coefficient of the planar mode kp is 44%; room temperature dielectric constant εr is 1049, and the corresponding mechanical quality factor Qm is 49.

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Effect of LiNbO3 on Piezoelectric Properties of K0.5Na0.5NbO3 Ceramics

Materials Science Forum ◽

10.4028/www.scientific.net/msf.654-656.2037 ◽

2010 ◽

Vol 654-656 ◽

pp. 2037-2040

Author(s):

Ming He Cao ◽

Zhuo Li ◽

Fan Li ◽

Hua Hao ◽

Han Xing Liu

Keyword(s):

Phase Transition ◽

Solid State ◽

Electrical Properties ◽

Phase Structure ◽

Composition Range ◽

Piezoelectric Properties ◽

Piezoelectric Ceramics ◽

Lead Free ◽

Polymorphic Phase Transition ◽

State Process

Lead-free (1-x)K0.5Na0.5NbO3–xLiNbO3 piezoelectric ceramics have been prepared by a conventional solid state process. The phase structure and the electrical properties of the ceramics were studied. A polymorphic phase transition (PPT) between the orthorhombic and tetragonal phases was identified in the composition range of 0.08<x<0.10. The ceramics near the PPT show better piezoelectric properties. At a level of 10mol% LiNbO3, the sample sintered at 1100oC for 1h exhibits optimal piezoelectric properties.

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