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

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.

PHASE TRANSITION, DIELECTRIC AND PIEZOELECTRIC PROPERTIES OF NaNbO3–Ba0.85Ca0.15(Ti0.9Zr0.1)O3 LEAD-FREE CERAMICS

2012 ◽  
Vol 05 (03) ◽  
pp. 1250033 ◽  
Author(s):  
YUQING LEI ◽  
HONG WU ◽  
DUNMIN LIN ◽  
QIAOJI ZHENG ◽  
XIAOCHUN WU ◽  
...  
Keyword(s):  
Phase Transition ◽  
Solid Solution ◽  
Phase Boundary ◽  
Morphotropic Phase Boundary ◽  
Piezoelectric Properties ◽  
Lead Free ◽  
High Concentration ◽  
Lead Free Ceramics ◽  
Sintering Method ◽  
Dielectric And Piezoelectric Properties

A new lead-free solid solution of (1–x) NaNbO 3-x Ba 0.85 Ca 0.15( Ti 0.9 Zr 0.1) O 3 was prepared by a traditional sintering method and its phase transition, dielectric and piezoelectric properties were studied. Ba 0.85 Ca 0.15( Ti 0.9 Zr 0.1) O 3 diffuses into NaNbO3 lattices to form a new solid solution with perovskite structure. The addition of Ba 0.85 Ca 0.15( Ti 0.9 Zr 0.1) O 3(x≥0.025) transforms NaNbO3 from antiferroelectric to ferroelectric. The diffusive ferroelectric–paraelectric phase transition is induced in the ceramics with high concentration of Ba 0.85 Ca 0.15( Ti 0.9 Zr 0.1) O 3. The ceramics with x = 0.05–0.125 possess large Pr values of 18.6–25.5 μC/cm2. A morphotropic phase boundary between tetragonal and orthorhombic phases is formed at 0.05 < x < 0.15, leading to a significant enhancement of piezoelectric properties. The ceramic with x = 0.125 situated near the morphotropic phase boundary exhibits the optimum piezoelectric properties: d33 = 151 pC/N and kp = 31.6%.

Phase transition, dielectric and piezoelectric properties of NaNbO3–Bi0.5Li0.5TiO3 lead-free ceramics

2012 ◽  
Vol 12 (6) ◽  
pp. 1523-1528 ◽  
Author(s):  
Lingling Fu ◽  
Dunmin Lin ◽  
Qiaoji Zheng ◽  
Xiaochun Wu ◽  
Lang Wu ◽  
...  
Keyword(s):  
Phase Transition ◽  
Piezoelectric Properties ◽  
Lead Free ◽  
Lead Free Ceramics ◽  
Dielectric And Piezoelectric Properties

Effects of YMnO3 Addition on Phase Structure, Microstructure and Electrical Properties of (Na0.515K0.485)0.94Li0.06(Nb0.8Ta0.2)O3 Lead-Free Ceramics

2014 ◽  
Vol 979 ◽  
pp. 167-170
Author(s):  
Pornsuda Bomlai
Keyword(s):  
Grain Size ◽  
Electrical Properties ◽  
Phase Structure ◽  
Dissipation Factor ◽  
Lead Free ◽  
Low Dielectric ◽  
Lead Free Ceramics ◽  
Dielectric Dissipation Factor ◽  
Sintering Method ◽  
Piezoelectric Devices

The (1-x)[(Na0.515K0.485)0.94Li0.06(Nb0.8Ta0.2)O3]-xYMnO3 (x = 0, 0.005, 0.01, 0.015 and 0.02) lead-free ceramics were synthesized by solid-state reaction sintering method. It was found that the addition of YMnO3 affected on the grain size, phase structure and electrical properties of (Na0.515K0.485)0.94Li0.06(Nb0.8Ta0.2)O3 ceramics. The grain size decreased with increasing YMnO3 content (x ≥ 0.01) and led to poor densification. The ceramic doped with 0.5 mol% YMnO3 showed good electrical properties such as d33 = 195 pC/N, kp = 43.9 %, Tc = 292 °C, TO−T = 35 °C, εr = 820 and rather low dielectric dissipation factor = 2.1%. This indicates that 0.5 mol% YMnO3 -doped (Na0.515K0.485)0.94Li0.06(Nb0.8Ta0.2)O3 piezoceramic is an alternative lead-free piezoelectric material for the development of piezoelectric devices working at high temperature.

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

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.

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

2013 ◽  
Vol 747 ◽  
pp. 781-784 ◽  
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).

Effects of Ball Milling on the Properties of (Ba1-xCax)(Ti0.92Sn0.08)O3 Lead-Free Ceramics

2017 ◽  
Vol 751 ◽  
pp. 417-422
Author(s):  
Onchuda Wattanapradit ◽  
Pornsuda Bomlai
Keyword(s):  
Grain Size ◽  
Ball Milling ◽  
Piezoelectric Properties ◽  
High Energy ◽  
Lead Free ◽  
Ca Addition ◽  
Lead Free Ceramics ◽  
Milling Method ◽  
Energy Ball ◽  
Dielectric And Piezoelectric Properties

The (Ba1-xCax)(Ti0.92Sn0.08)O3 (x = 0 and 0.02) lead-free ceramics were prepared by using different ball-milling method and time (common ball milling 24 h, high energy ball milling 1 and 3 h). The two-step sintering method was used for sintered the samples. The densification, structure, dielectric and piezoelectric properties of the ceramics were investigated. The results showed that Ca addition could reduce sintering temperature effectively and enhanced densification at lower temperature when using the common ball-milling type. The XRD patterns of (Ba1-xCax) (Ti0.92Sn0.08)O3 ceramics revealed the change in crystal symmetries from tetragonal to cubic phase with increasing Ca content from 0 to 0.02. However, the crystal structure did not change due to the effect of ball-milling method. Ca incorporation caused a decrease of the grain size and Curie temperature. Moreover, the largest grain size was found in the x = 0 ceramics with 24 h-common ball-milling, whereas the small size (< 5 µm) was obtained for the x = 0.02 ceramics. The dielectric and piezoelectric properties were also affected to Ca addition and ball-milling. High piezoelectric coefficient of d33 = 173 pC/N, dielectric constant εr ~ 3200 and dissipation factor tand ~ 0.05 were obtained for the x = 0 sample with high energy ball-milling for 1 h.

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