KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Search Results

Now showing 1 - 10 of 12

Some of the metrics are blocked by your
consent settings
Lead-free (Ba,Ca)(Ti,Zr)O3 ceramics within the polymorphic phase region exhibiting large, fatigue-free piezoelectric strains
(2017-11-05)
Chaiyo, Nopsiri
;
Cann, David P.
;
Vittayakorn, Naratip
Lead-free xBaZrO<inf>3</inf>-(0.85-x)BaTiO<inf>3</inf>-0.15CaTiO<inf>3</inf>; x = 0.00–0.20 (xBZ) ceramics were prepared successfully using the conventional solid-state reaction method. Unipolar electric-field-induced strains of the composition x = 0.125 in the polymorphic phase region (PPR) composition show an extraordinarily high normalized piezoelectric coefficient (d<inf>33</inf>⁎) of 2244 pm/V with relatively low hysteresis at a low electric field of 5 kV/cm, which is higher than that of most reported lead-free ceramics. The PPR composition also exhibits excellent fatigue resistance to bipolar electric cycling with negligible loss of electric-field-induced strain after 106 cycles. A two-phase mixture model featuring short-range ordering, which is dispersed in the long-range ferroelectric phase, is proposed to explain the outstanding piezoelectric properties. The reversible electric-field-induced phase transition between the two states is responsible for the large normalized piezoelectric coefficient and fatigue resistance. Under repeated electric cycling, the domains become more dynamic, and the change in domain configuration becomes easier due to decreased energy requirement upon polarization reversal. Furthermore, the ceramic shows single crystal-like behavior characterized by a nearly vertical slope in the polarization hysteresis data, which correlates to the electric field induced transformation from a multi-domain state to a single-domain state. This environmentally benign lead-free ceramic, with outstanding properties, has great potential use for highly responsive and reliable actuators.
Some of the metrics are blocked by your
consent settings
Phase transitions, ferroelectric, and piezoelectric properties of lead-free piezoelectric xBaZrO3–(0.25−x)CaTiO3–0.75BaTiO3 ceramics
(2015-09-25)
Chaiyo, Nopsiri
;
Cann, David P.
;
Vittayakorn, Naratip
Lead-free xBaZrO<inf>3</inf>–(0.25−x)CaTiO<inf>3</inf>–0.75BaTiO<inf>3</inf>; x = 0.00–0.25 ceramics were successfully prepared using the conventional solid-state reaction method. Analysis of the sintered ceramics showed that all compositions exhibited a pure phase perovskite. The effects of composition on the phase transition, ferroelectric properties, and piezoelectric properties were studied. With the increasing BaZrO<inf>3</inf> content, the phase transition temperature (T<inf>C</inf>) decreased and the coercive field E<inf>c</inf> decreased. The phase diagram featuring a cubic–rhombohedral–tetragonal triple point (x ~ 0.125) was derived from X-ray diffraction data and dielectric data as a function of temperature. Compositions near the convergence region exhibited the maximum peak in permittivity of ~11,400 at T<inf>C</inf>. In addition, the morphotropic phase boundary compositions showed an enhancement in ferroelectric and piezoelectric properties. The composition 0.125BaZrO<inf>3</inf>–0.125CaTiO<inf>3</inf>–0.75BaTiO<inf>3</inf> exhibited the highest strain values of 0.14 % and a d<inf>33</inf>* of 474 pm/V.
Some of the metrics are blocked by your
consent settings
Phase transitional behavior and dielectric properties of lead free (1-x)(K0.5Na0.5)NbO3-xBi (Zn0.5Ti0.5)O3 ceramics
(2009-06-24)
Sutapun, Manoon
;
Huang, Chien Chih
;
Cann, David P.
;
Vittayakorn, Naratip
Lead-free ceramics based on potassium sodium niobate [(K<inf>0.5</inf>Na<inf>0.5</inf>)NbO<inf>3</inf>; KNN]-bismuth zinc titanate [Bi(Zn<inf>0.5</inf>Ti<inf>0.5</inf>)O<inf>3</inf>; BZT] were prepared by the modified-conventional mixed oxide route with normal sintering. The crystal structure and ferroelectric phase transitions were studied by means of X-ray diffraction, thermal and dielectric measurements. The ceramics with perovskite structure were in orthorhombic phase at x ≤ 0.010. When reaching 0.01 < x ≤ 0.03, they became a rhombohedral perovskite structure; and with increasing BZT content, cubic within the studied composition range. The phase Bi<inf>2</inf>Ti<inf>2</inf>O<inf>7</inf> with cubic structure began to appear at x > 0.25 and became dominant while increasing the content of BZT. Furthermore, the phase transition temperature of orthorhombic-tetragonal (T<inf>O-T</inf>) and tetragonal-cubic (T<inf>C</inf>) decreased when a small amount of BZT was added. As the amount of BZT concentration increased, the structure became denser, and well developed grain morphology with almost no porosity was finally obtained. © 2008 Elsevier B.V. All rights reserved.
Some of the metrics are blocked by your
consent settings
Phase transitions and dielectric properties in Bi(Zn1/2Ti 1/2)O3-(Na1-yLiy)NbO3 perovskite solid solutions
(2009-03-01)
Huang, Chien Chih
;
Vittayakorn, Naratip
;
Prasatkhetragarn, Anurak
;
Gibbons, Brady J.
;
Cann, David P.
Perovskite solid solutions based on the system Bi(Zn<inf>1/2</inf>Ti <inf>1/2</inf>)O<inf>3</inf>-NaNbO<inf>3</inf> were obtained via solid-state processing techniques. The crystal structure and ferroelectric phase transitions were studied by means of X-ray diffraction and dielectric measurements. A stable perovskite phase was obtained for Bi(Zn<inf>1/2</inf>Ti <inf>1/2</inf>)O<inf>3</inf> substitutions up to 10mol%. The dielectric characterization revealed that as the Bi(Zn<inf>1/2</inf>Ti<inf>1/2</inf>)O <inf>3</inf> content increased, the transition temperature decreased and the transition peak became very diffuse. The polarization hysteresis loop and strain measurements presented evidence of an induced ferroelectric phase with 1 mol % Bi(Zn<inf>1/2</inf>Ti<inf>1/2</inf>)O<inf>3</inf> substitutions. The planar coupling factor (k<inf>p</inf>) for 0.01Bi(Zn<inf>1/2</inf>Ti <inf>1/2</inf>)O<inf>3</inf>-0.99NaNbO<inf>3</inf> was measured to be 0.28. In addition, with the substitution of Li for Na in the Bi(Zn<inf>1/2</inf>Ti <inf>1/2</inf>)O<inf>3</inf>-(Na<inf>1-y</inf>Li<inf>y</inf>)NbO<inf>3</inf> system, the diffuseness of the transition peak decreased and the transition temperature increased. © 2009 The Japan Society of Applied Physics.
Some of the metrics are blocked by your
consent settings
Dielectric properties of Pb[(1-x)(Zr1/2Ti1/2)- x(Zn1/3Ta2/3)]O3 ceramics prepared by columbite and wolframite methods
(2008-06-01)
Banlue, Wanwimon
;
Vittayakorn, Naratip
;
Huang, Chien Chih
;
Cann, David P.
Polycrystalline samples of Pb[(1 - x)(Zr<inf>1/2</inf>Ti<inf>1/2</inf>) - x(Zn<inf>1/3</inf>Ta<inf>2/3</inf>)]O <inf>3</inf> , where x = 0.1-0.5 were prepared by the columbite and wolframite methods. The crystal structure, microstructure, and dielectric properties of the sintered ceramics were investigated as a function of composition via X-ray diffraction (XRD), scanning electron microscopy (SEM), and dielectric spectroscopy. The results indicated that the presence of Pb(Zn<inf>1/3</inf>Ta<inf>2/3</inf>)O<inf>3</inf> (PZnTa) in the solid solution decreased the structural stability of overall perovskite phase. A transition from tetragonal to pseudo-cubic symmetry was observed as the PZnTa content increased and a co-existence of tetragonal and pseudo-cubic phases was observed at a composition close to x = 0.1. Examination of the dielectric spectra indicated that PZT-PZnTa exhibited an extremely high relative permittivity at the MPB composition. The permittivity showed a ferroelectric to paraelectric phase transition at 330 °C with a maximum value of 19,600 at 100 Hz at the MPB composition. © 2008 Springer Science+Business Media, LLC.
Some of the metrics are blocked by your
consent settings
Synthesis and dielectric and ferroelectric properties of ceramics in (1 - X)Pb(Zr1/2Ti1/2)O3-(x)Pb(Co 1/3Nb2/3)O3 system
(2008-02-15)
Prasatkhetragarn, Anurak
;
Vittayakorn, Naratip
;
Ananta, Supon
;
Yimnirun, Rattikorn
;
Cann, David P.
Ceramics in a PZT-PCN system with the formula (1 - x)Pb(Zr <inf>1/2</inf>Ti<inf>1/2</inf>)O<inf>3</inf>-(x)Pb(Co<inf>1/3</inf>Nb <inf>2/3</inf>)O<inf>3</inf>, where x = 0.1-0.5, were prepared using a solid-state mixed-oxide technique (the columbite-wolframite precursor method). The phase formation behavior and microstructure were studied using X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM), respectively. The dielectric and ferroelectric properties of the compounds were studied and discussed. Phase-pure perovskites of PZT-PCN ceramics were obtained over a wide compositional range. In addition, the XRD, dielectric, and ferroelectric properties confirmed that the morphotropic phase boundary (MPB) composition between the tetragonal and pseudo cubic phases of this system lied between 0.2 ≤ × ≤ 0.3. © 2008 The Japan Society of Applied Physics.
Some of the metrics are blocked by your
consent settings
Observation of high dielectric constants in x (Pb (Zn13 Nb23) O3 - (0.2-x) Pb (Ni13 Nb23) O3 -0.8Pb (Zr12 Ti12) O3 ternary solid solutions
(2007-11-23)
Nabunmee, Sucheewan
;
Rujijanagul, Gobwute
;
Vittayakorn, Naratip
;
Cann, David P.
In the present work, we demonstrate the results of combining two excellent ferroelectric materials at their morphotropic phase boundary compositions, i.e., 0.2 (Pb (Zn13 Nb23) O3 -0.8Pb (Zr12 Ti12) O3 (0.2PZN-0.8PZT) and 0.2Pb (Ni13 Nb23) O3 -0.8Pb (Zr12 Ti12) O3 (0.2PNN-0.8PZT) to form a ternary solid solution of x (Pb (Zn13 Nb23) O3 - (0.2-x) Pb (Ni13 Nb23) O3 -0.8Pb (Zr12 Ti12) O3 (xPZN- (0.2-x) PNN-0.8PZT) which exhibits superior dielectric properties. Examination of the dielectric spectra indicated that the ternary system exhibits a very high relative permittivity of 49 800 (at 10 kHz) for the composition at x=0.10. In addition, an increased amount of PZN was observed to enhance the ferroelectric properties of the system. © 2007 American Institute of Physics.
Some of the metrics are blocked by your
consent settings
Phase transitions and ferroelectric properties in BiScO3 -Bi (Zn12 Ti12) O3 -BaTiO3 solid solutions
(2007-09-10)
Huang, Chien Chih
;
Cann, David P.
;
Tan, Xiaoli
;
Vittayakorn, Naratip
Ceramics solid solutions within the ternary perovskite system Bi (Zn12 Ti12) O3 -BiScO3 -BaTiO3 were synthesized via solid-state processing techniques. The crystal structure of sintered ceramics was analyzed by x-ray diffraction. A stable perovskite phase was obtained for all compositions with a BaTiO3 content greater than 50 mol %. Furthermore, a change in symmetry from pseudocubic to tetragonal was observed as the mole fraction of BaTiO3 increased. Dielectric measurements show a dielectric anomaly associated with a phase transformation over the temperature range of 30 °C-210 °C for all compositions. Examination of the polarization hysteresis behavior revealed weakly nonlinear hysteresis loops. With these data, ferroelectric phase diagrams were derived showing the transition between the pseudocubic relaxor behavior to the tetragonal normal ferroelectric behavior. This transition was also correlated with changes in the diffuseness parameter. © 2007 American Institute of Physics.
Some of the metrics are blocked by your
consent settings
The effect of post-sintering annealing induced extrinsic dielectric properties in PZT-PZN ceramics
(2007-08-02)
Vittayakorn, Naratip
;
Cann, David P.
;
Rujijanagul, Gobwute
;
Tunkasiri, Tawee
Pb[(Zr1/2Ti1/2)0.7(Zn1/3Nb2/3)0.3]O3 (PZT-30PZN) powder was prepared using the columbite precursor method. The phase development of calcined powder precursors was analyzed by X-ray diffraction. Dielectric and ferroelectric properties of the as-sintered and annealed samples were measured and correlated with microstructure. The morphology evolution was determined by a scanning electron microscopy (SEM) technique. The as-sintered ceramic exhibited weak relaxor-ferroelectric behavior, with a relatively low dielectric constant maximum measured at 1 kHz (Km@1 kHz) of 14 000. Annealing resulted in a transition to normal-ferroelectric-like behavior, a shift in the dielectric maximum temperature from 310C to 300C, and a dramatic increase of Km@1 kHz to a maximum value of 25 100 for the longer anneal. After thermal annealing at 900C for 1 week a strong enhancement of remanent polarization (Pr) was observed.
Some of the metrics are blocked by your
consent settings
Investigation of the influence of thermal treatment on the morphologies, dielectric and ferroelectric properties of PZT-based ceramics
(2007-08-16)
Vittayakorn, Naratip
;
Rujijanagul, Gobwute
;
Cann, David P.
Pb[(Zr<inf>1/2</inf>Ti<inf>1/2</inf>)<inf>0.9</inf>(Zn<inf>1/3</inf>Nb<inf>2/3</inf>)<inf>0.1</inf>]O<inf>3</inf> (PZT-10PZN) powder was prepared using the columbite precursor method. The phase development of calcined powder precursors was analyzed by X-ray diffraction. Dielectric and ferroelectric properties of the as-sintered and annealed samples were measured and correlated with the microstructure. The morphological evolution was determined by scanning electron microscopy (SEM). The as-sintered ceramic exhibited weak normal-ferroelectric behavior, with a relatively low dielectric constant maximum measured at 1 kHz (ε<inf>rmax</inf> at 1 kHz) of 13,000. Annealing resulted in a transition to relaxor-ferroelectric-like behavior, a shift in the dielectric maximum temperature from 360 to 350 °C, and a dramatic increase in ε<inf>rmax</inf> at 1 kHz to a maximum value of 35,000 for the longer anneal. Furthermore, after thermal annealing at 900 °C for 1 week the composition shifted close to the MPB with a great reduction in the transition temperature and a broadening of the dielectric constant maximum. A strong enhancement of the remanent polarization (P<inf>r</inf>) was also observed. © 2006 Elsevier B.V. All rights reserved.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results