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High piezoelectric activity in lead-free BaTiO3-BaZrO3-CaTiO3 ceramics with near polymorphic phase boundary
(2019-01-02)
Sutapun, Manoon
;
Vittayakorn, Naratip
Lead-free 0.88BaTiO<inf>3</inf>–(0.12-x)BaZrO<inf>3</inf>–xCaTiO<inf>3</inf> (BT-BZ-xCT) ceramics were fabricated via solid state reaction. The effect of CaTiO<inf>3</inf> content on crystal structure, phase transition, and electrical properties was investigated systematically. The crystal structure and phase transition of ceramics were characterized by X-ray diffraction (XRD), Raman spectra and dielectric measurement. Results show that ceramic in the composition, x = 0.02, exhibits a rhombohedral structure. Ceramics with increasing CT content transformed from a rhombohedral to orthorhombic structure in the composition, x = 0.04, and eventually became a tetragonal structure at the composition, x ≥ 0.08. The polymorphic phase boundary (PPB) was observed at the composition, x = 0.06, with coexistence of orthorhombic and tetragonal phases showing at almost room temperature. This PPB composition exhibited a high piezoelectric response (d<inf>33</inf>*) of 1,150 pm/V at 10 kV/cm as an electric field was applied. These results indicate that the materials studied have potential as candidates for lead-free piezoelectric ceramics.
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Phase transition, dielectric and piezoelectric properties of lead-free piezoelectric (K1/2Na1/2)NbO3 - Bi(Zn2/3Nb1/3)O3 ceramics
(2016-01-02)
Sutapun, Manoon
;
Muanghlua, Rangson
;
Vittayakorn, Naratip
The lead-free piezoelectric ceramics on the binary system of (1-x)(K<inf>1/2</inf>Na<inf>1/2</inf>)NbO<inf>3</inf>-xBi(Zn<inf>2/3</inf>Nb<inf>1/3</inf>)O<inf>3</inf> [(1-x)KNN-xBZnN]; x = 0.01-0.10 were fabricated by the solid state reaction method. The structure and phase transition were determined by X-ray diffraction.The results of XRD patterns suggested that Bi(Zn<inf>2/3</inf>Nb<inf>1/3</inf>)O<inf>3</inf> completely diffuse into the (K<inf>1/2</inf>Na<inf>1/2</inf>)NbO<inf>3</inf> lattices to form a solid solution. The crystal structure was in an orthorhombic phase for x ≤ 0.01. When reaching 0.01 < x ≤ 0.07, crystal structure became a rhombohedral phase and transformed to a pseudo-cubic structure for x > 0.07. The dielectric data shows that the amount of Bi(Zn<inf>2/3</inf>Nb<inf>1/3</inf>)O<inf>3</inf> added in the (K<inf>1/2</inf>Na<inf>1/2</inf>)NbO<inf>3</inf> decreases the ferroelectric - paraelectric transition temperature progressively. Furthermore, optimum piezoelectric and ferroelectric properties were observed at the composition, x = 0.01: effective piezoelectric coefficients (d<inf>33</inf>) = 498 pm/V, remanent polarization (P<inf>r</inf>) = 23.3 μC/cm<sup>2</sup>, coercive field (E<inf>c</inf>) = 14 kV/cm, maximum strain (Sma<inf>x</inf>) = 0.3% and Curie temperature (T<inf>C</inf>) = 380°C. The results of this study show that KNN with a small amount of Bi(Zn<inf>2/3</inf>Nb<inf>1/3</inf>)O<inf>3</inf> (x = 0.01) can be one of lead-free piezoelectric ceramic candidate.
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High piezoelectric response in the new coexistent phase boundary of 0.87BaTiO3-(0.13-x)BaZrO3-xCaTiO3
(2015-12-05)
Sutapun, Manoon
;
Vittayakorn, Wanwilai
;
Muanghlua, Rangson
;
Vittayakorn, Naratip
An investigation of the coexistent ferroelectric phase was carried out on the ternary system of 0.87BaTiO<inf>3</inf>-(0.13-x)BaZrO<inf>3</inf>-xCaTiO<inf>3</inf> [abbreviated as BT-BZ-xCT (where 0.00≤x≤0.13)]. Temperature-, frequency-dependent dielectric data, electric field-dependent strain and polarization as a function of composition are presented in order to understand the relationships of structure-properties and find the high piezoelectric response in this system. Results showed that ceramics in the composition range of 0.00≤x<0.04 were of a rhombohedral structure and transformed into a tetragonal structure at x>0.06. The multiphase coexistence of the rhombohedral and tetragonal phase in this system was identified at x=0.06. A large, virtually hysteresis-free electric field induced strain of 0.23% was achieved with the composition, x=0.06, at 40kV/cm on the boundary between rhombohedral and tetragonal phase. This relates to an extraordinarily high and normalized piezoelectric coefficient (S<inf>max</inf>/E<inf>max</inf>) of 1280pm/V, which was reached at a low electric field applied at 10kV/mm. These results indicated that a high piezoelectric response may stem primarily from the rhombohedral-tetragonal phase boundary, due to greater lattice softening and reduced energy barriers for polarized rotation.
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Rapid synthesis of potassium sodium niobate (K 1/2Na 1/ 2NbO3) lead-free piezoelectric powder using the combustion method
(2013-12-01)
Chaiyo, Nopsiri
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Muanghlua, Rangson
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Wongprasert, Yothin
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Seeharaj, Panpailin
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Vittayakorn, Naratip
Potassium sodium niobate (K1/<inf>2</inf>Na1/<inf>2</inf>NbO<inf>3</inf>) powder was synthesized successfully by the combustion synthesis. The raw materials of KNO<inf>3</inf>, NaNO<inf>3</inf> and Nb<inf>2</inf>O<inf>5</inf> were used with glycine as fuel. The thermal behaviour of the precursor was determined using thermo gravimetric analysis (TGA) and derivative thermo gravimetric (DTG) analysis. The conditions for preparing perovskite phase formation, influence of the fuel-to-oxidizer molar ratio, and crystal structure were characterized by the X-ray diffraction technique (XRD) and Fourier transform infrared (FTIR) spectroscopy. The morphology and particle size were investigated through a scanning electron microscope (SEM). © 2013 Copyright Taylor and Francis Group, LLC.
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Phase transition behaviour and electrical properties of lead-free (K 0.5Na0.5)NbO3-LiNbO3-LiSbO 3 piezoelectric ceramics
(2011-05-01)
Muanghlua, Rangson
;
Niemcharoen, Surasak
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Sutapun, Manoon
;
Boonchom, Banjong
;
Vittayakorn, Naratip
The ternary system of 0.945(K<inf>0.5</inf>Na<inf>0.5</inf>NbO <inf>3</inf>)-(0.055 - x)LiNbO<inf>3</inf>-xLiSbO<inf>3</inf> [0.945KNN-(0.055 - x)LN-xLS]; x = 0.0-0.055 lead-free piezoelectric ceramics was fabricated by the conventional mixed oxide method with normal sintering. The crystal structure was studied by means of X-ray diffraction (XRD). The results of XRD patterns show that complete solid solutions of the mixed phase between the orthorhombic and tetragonal perovskite phase were observed. The DSC and dielectric data show that the amount of LiSbO<inf>3</inf> in K<inf>0.5</inf>Na<inf>0.5</inf>NbO <inf>3</inf>-LiNbO<inf>3</inf> solid solution slightly decreases the paraelectric cubic-ferroelectric tetragonal phase transition (T<inf>C</inf>) to a low temperature. Furthermore, good dielectric and piezoelectric properties were observed at composition, x = 0.03. The polymorphic phase transition between the orthorhombic and tetragonal phases plays a very important role in enhancement of the piezoelectric properties of KNN-LN-LS ceramics. © 2010 Elsevier B.V. All rights reserved.

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