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In this study, for developing the multilayer piezoelectric actuator, the (Na,K)(Nb,Sb)O3–(Bi,Na)ZrO3 ceramics were manufactured and their dielectric and piezoelectric properties were investigated. The manufactured ceramics showed the excellent physical properties: density = 4.56 g/cm2, kp = 0.47, Qm = 50, er = 1944, and d33 = 313 pC/N, suitable for piezoelectric actuator. The properties of the piezoelectric actuators are as follows: at the average size of 30.47 mm $$\times$$ 17.92 mm $$\times$$ 1.0 mm, resonance frequency fr = 69.87 kHz, anti-resonance frequency fa = 71.20 kHz, kp = 0.22, d33 = 1120 pC/N were appeared, respectively. The three piezoelectric actuators connected in parallel showed the high vibration acceleration of 2.0G at 580 Hz under 70 V, suitable for the force feedback actuator.

Nowadays, piezoelectric speakers have been actively studied for the applications to smartphone, TV monitor, and car audio system. Accordingly, for developing the piezoelectric speaker composition c...

In this study, 1, 2, 3, 4, 5, and 6 layer ceramic piezoelectric actuator were designed and simulated according to the variations of ceramic layer by ATILA software in order to develop the f...

In this study, (Na,K,Li)(Nb,Sb,Ta)O3 ceramics substituted with (Sr,Ca)ZrO3 by conventional solid state method were manufactured and their dielectric and piezoelectric properties were investigated. ...

(1 − x)(NKL)(NST)O3 − x(Ba0.90Ca0.1)ZrO3 ceramics with (Ba0.90Ca0.1)ZrO3 substitution were synthesized and their physical characteristics were systematically analyzed. All specimens showed typical perovskite structure and no second phase was found according to (Ba0.90Ca0.1)ZrO3 substitution. When Ba0.90Ca0.1)ZrO3 substitution x = 0.02, the highest piezoelectric characteristics of d33 = 260 pC/N, er = 1904, kp = 0.4102, Qm = 106 were found for piezoelectric devices such as actuators and ultrasonic sensors.

In this study, 0.97(Na0.52K0.443Li0.037)(Nb0.96-xSb0.04Tax)O3–0.03(Bi0.5Na0.5)0.9(Sr)0.1ZrO3 ceramics were fabricated as a function of Ta substitution by conventional solid state method in order to develop the excellent composition ceramics for piezoelectric actuator, and their dielectric and piezoelectric properties were investigated. As the chemical composition results of 0.97(Na0.52K0.443Li0.037)(Nb0.96-xSb0.04Tax)O3–0.03(Bi0.5Na0.5)0.9(Sr)0.1ZrO3 system, we obtained the following results: When Ta was substituted for the ceramics, all the ceramics possessed a perovskite structure. When the substitution of Ta was 0, 0.01 and 0.02, Morphotropic phase boundary (MPB) region, which is coexist with rhombodedral phase and tetragonal phase was appeared. With further increasing the Ta substitution, the ceramics showed the strengthened tetragonal phase together with the coexistence of rhombodedral phase and tetragonal phase. The NKN-BNZ ceramics with x = 0.02 showed excellent piezoelectric properties. The density (ρ), piezoelectric constant (d33), planar piezoelectric coupling coefficient (kp), mechanical quality factor (Qm), and dielectric constant (er) were optimized as 4.456 (g/cm3), 269 (pC/N), 0.419, 51, 1644, respectively.

In this works, in order to develop the composition ceramics for a capacitor with the excellent dielectric properties, (Ba0.86Ca0.14) (Ti0.85Zr0.12Sn0.03) O3(abbreviated as BCTZ) ceramics were fabricated with the amount of Bi2O3. All specimens showed a typical perovskite structure. As the Bi2O3 addition was increased, secondary phase was found. When x = 0.006, the maximum value of er = 6043 was shown at 0 °C. At the 0.003 mol Bi2O3, the most excellent dielectric and TCC properties were obtained. Namely, the dielectric constant (er), the range of TCC from − 20 to 80 °C, Curie temperature were 5015, − 2 to + 48%, and 40 °C, respectively.

In this paper, in order to develop the composition ceramics with the high piezoelectric properties for ultrasonic transducer, Pb[(Mn1/3Nb2/3)x(Ni1/3Nb2/3)0.10(Zr0.48Ti0.52)0.90−x]O3 ceramics were fabricated with the variation of Pb(Mn1/3Nb2/3)O3. The effects of Pb(Mn1/3Nb2/3)O3 (abbreviated as PMN) on their microstructure and piezoelectric properties were systematically investigated. The tetragonality was decreased in the ceramics with the increase of Pb(Mn1/3Nb2/3)O3. When Pb(Mn1/3Nb2/3)O3 and sintering temperature were 8 mol%, 940 °C, respectively, the excellent physical properties of d33 = 302 pC/N, er = 1390, kp = 0.542, Qm = 1378 were obtained in the specimens for ultrasonic transducer.

In this paper, in order to develop the composition ceramics for piezoelectric actuator. (1 − x)(Na0.52K0.443Li0.037)(Nb0.883Sb0.08Ta0.037)O3 − x(Sr0.95Ca0.05)ZrO3 ceramics were sintered at 1020 °C by the conventional solid-state method. The effects of (Sr0.95Ca0.05)ZrO3 substitution on their microstructure and piezoelectric properties were systematically investigated. The orthorhombic-tetragonal coexistence phase has been found in the ceramics with x = 0.01, 0.015 and x = 0.02. The maximum value of d33 was 322 pC/N at x = 0.025 composition ceramics with the rhombohedral phase. The (Sr0.95Ca0.05)ZrO3 substitution increased the density and then aided the grain growth of specimens. When x = 0.01, the optimal physical properties of d33 = 254 pC/N, er = 1096, kp = 0.46, and Qm = 156 were obtained, respectively, for piezoelectric actuator application.

In this study, in order to develop relaxor ferroelectric ceramics with large electrocaloric effect, (Pb0.88La0.08)(Zr0.65Ti0.35)O3 ceramics were manufactured using conventional solid-state reaction...

Polyethylene/carbon black(PE/CB) composites have been widely used in various application devices such as heating element, temperature sensor and current limiter due to its positive temperature coef...

In this study, in order to develop the composition ceramics for ultrasonic sensor application, Pb0.985Bi0.01(Co1/2W1/2)0.03(Ni1/3Nb2/3)0.09(ZrxTi1-x)0.88O3+0.25wt% CuO (abbreviated as PCW-PNN-PZT) system ceramics were prepared with the variations of x and then their phase microstructure, piezoelectric and dielectric characteristics were investigated with the variations of x. The compositions near the morphotropic phase boundary (MPB) appeared when x = 0.495. Moreover, the PCW-PNN-PZT ceramics could be sintered at low temperature of 920°C by adding sintering aids CuO. At sintering temperature of 920°C and x = 0.495 specimen, the density (ρ), electromechanical coupling factor(kp), dielectric constant (ϵr), mechanical quality (Qm) and piezoelectric constant (d33) piezoelectric figure of merit (d33·g33) indicated the optimal value of 7.94 g/cm3. 0.65, 1959, 356, 486 pC/N, and 15.56 [pm2/N], respectively, suitable for ultrasonic sensor application. The CuO was proved to lower the sintering temperature ...

In this study, in order to develop piezoelectric ceramics with high piezoelectric d 31 coefficient and high Curie temperature (Tc), Pb(Mg 1/2 W 1/2 ) 0.03 (Ni 1/3 Nb 2/3 ) 0.09 (Zr 0.5 Ti 0.5 ) 0.88 O 3 ceramics doped with sintering aids were fabricated using a columbite precursor method. The crystal structure, dielectric and piezoelectric properties were investigated as a function of calcination temperature. At the sintering temperature of 920 °C, the optimal values of density = 7.83(g/cm 3 ), piezoelectric coefficient(d 31 ) = 263pC/N, piezoelectric coefficient(d 33 ) = 620pC/N, planar electromechanical coupling coefficient (k p ) = 0.689, mechanical quality factor (Q m ) = 100, dielectric constant(e r ) = 2524 and Curie temperature (Tc) = 340 °C were obtained from the ceramics with the two step calcination temperature of 1st = 1130 °C, 2nd = 780 °C, respectively, for haptic actuator application.

In this study, boost DC-DC converter was designed and manufactured in order to light Light Emitting Diode (abbreviated as LED) using piezoelectric energy harvesting device. Piezoelectric energy harvesting device was fabricated using PMW-PNN-PZT ceramics with excellent piezoelectric properties of kp = 0.60, d33 = 518 (pC/N), g33 = 25.9 (×10−3Vm/N), and d33.g33 = 13.416(pm2/N). Cantilever type with the dimension of 80 × 12× 1.5mm3 was used to generate the power. Piezoelectric energy harvesting device generated an AC 2.19V at the driving frequency of 139 Hz under 3.5G. Output voltage of the piezoelectric energy harvesting device was rectified as DC 1.46V, and then charged on the capacitors. The DC 1.46V was used as the input voltage of the boost DC-DC converter. Output voltage of boost DC-DC converter exhibited DC 5.01V, indicating the sufficient value for lightening LED.

The particle sizes of 0.95(K0.5Na0.5)NbO3-0.05BaTiO3 powder were controlled by secondary milling time after calcination. The average particle sizes, Dmean, of 0.95(K0.5Na0.5)NbO3-0.05BaTiO3 powders were critically changed from 14.31 μm to 0.91 μm by secondary milling time. The dielectric and piezoelectric properties of 0.95(K0.5Na0.5)NbO3-0.05BaTiO3 ceramics depended on the particle sizes of powders after calcination and the secondary milling process. As secondary milling times after calcination were increased to more than 48 hr, the dielectric and piezoelectric properties of 0.95(K0.5Na0.5)NbO3-0.05BaTiO3 ceramics were deteriorated.

Lead-free (Ba0.85Ca0.15)(Ti0.915Zr0.085)O3 + x wt%ZnO piezoelectric ceramics were synthesized using a conventional solid state sintering method and the effect of ZnO addition on their piezoelectric and dielectric properties was investigated. The X-ray diffraction date exhibited that ZnO diffuses into the lattice of (Ba0.85Ca0.15)(Ti0.915Zr0.085)O3 (abbreviated as BCTZ) and pure perovskite structure phase was formed at all the specimens, And no secondary phases are observed in the measurement range of XRD. In addition, all the specimens showed tetragonal phase structure. The Curie temperature of BCTZ ceramics decreases with increasing the ZnO content. At the 0.2 wt% ZnO added (Ba0.85Ca0.15)(Ti0.915Zr0.085)O3 ceramics sintered at 1360°C, the optimized piezoelectric properties were obtained; piezoelectric constant(d33) = 348 [pC/N], dielectric constant(ϵr) = 3263, mechanical quality factor(Qm) = 267, electromechanical coupling factor(kp) = 0.41, respectively.

In this study, in order to develop lead-free composition for piezoelectric actuator applications, (Na0.525K0.48-x)(Nb0.92-xSb0.08)O3 + 0.25wt%Bi2O3 + xLiTaO3 (x = 0.036, 0.037, 0.038, 0.039, 0.040) composition ceramics were fabricated by the normal sintering technique. The piezoelectric properties of resultant ceramics were studied with a special emphasis on the varying of LiTaO3. The structure of the specimen exhibits an orthorhombic perovskite structure. The grain size of the specimen increased with increasing the content of LiTaO3 substitution. High physical properties of the piezoelectric constant d33 = 317 pC/N, electromechanical coupling factor kp = 0.466, dielectric constant ϵr = 1913, and density ρ = 4.527 g/cm3 were obtained from the composition ceramics with x = 0.037. Also, at this composition, Δkp/kp20°C and Δfr/fr20°C showed the maximum value of −0.041 and −0.022 at −20°C and 50°C, respectively. Accordingly, it is considered that the temperature stability of x = 0.037 composition ceramics is ...

In this study, lead-free (Ba0.85Ca0.15)(Ti1-xZrx)O3 ceramics and a bimorph-type piezoelectric actuator were fabricated using the normal oxide-mixed sintering method, and their dielectric properties, microstructure, and displacement properties were investigated. From the results of X-ray diffraction, the pattern of the specimen has a pure perovskite structure. In addition, no secondary impurity phases were found. The excellent piezoelectric coefficient of d 33 =454 pC/N, the electromechanical coupling factor kp =0.51, the dielectric constant er =3,657, the mechanical quality factor Qm =239, and Tc(Tetragonal-Cubic) =90℃ were shown at x= 0.085. Δkp/kp20℃ and Δfr/fr20℃ showed the maximum value of -0.255 and 0.111 at -20℃ and 80℃, respectively. The maximum total-displacement was 60 μm under the input voltage of 50 V. As a result, it is considered that lead-free (Ba0.85Ca0.15)(Ti1-xZrx)O3 ceramics is a promising candidate for piezoelectric actuator application for x= 0.085.

In this study, modified (Na,K,Li)(Nb,Ta)O3((Na x K1-x )0.96Li0.04(Nb0.90Ta0.10) 0.998Zn0.005O3) ceramics were fabricated using a normal sintering technique. The dielectric and piezoelectric properties of the resulting ceramics were studied with special emphasis on the varying sodium concentration. The results of X-ray diffraction patterns show that the specimen exhibits an orthorhombic perovskite phase structure. High physical properties of d33 = 261 pC/N, kp = 0.44, er = 735, ρ = 4.53 g/cm3 and d33 · g33 = 10.47 pm2/N were obtained from the composition ceramics with x = 0.56 at room temperature. Δkp/kp20°C and Δf r/f 20°C showed the maximum value of 0.034 and −0.025 at 40 °C and 50 °C, respectively. Also, the temperature stability of d33, g33 and d33 · g33 of specimen with x = 0.56 was an excellent. Therefore, it is considered that the temperature stability of electrical properties is suitable for the applications of piezoelectric actuator, sensor and energy harvester.

In this study, (Ba0.85Ca0.15)(Ti1−xZrx)O3 + 0.004 CuO lead-free piezoelectric ceramics were fabricated using a conventional solid state reaction technique. The X-ray diffraction patterns indicated that all specimens exhibit pure perovskite phase, and no secondary phases. The effects of Zr substitution on microstructure and piezoelectric characteristic and dielectric properties of BCTZ ceramics were systematically investigated. At the calcination temperature of 1200°C and sintering temperature of 1430°C, relatively good properties of piezoelectric constant (d33) = 454 [pC/N], electromechanical coupling factor(kp) = 0.51, electromechanical quality factor(Qm) = 239, dielectric constant(ϵr) = 3657 were obtained from x = 0.085, respectively. However, the excellent physical properties were obtained when x = 0.10, Taking into consideration the Curie temperature and piezoelectric properties of piezoelectric properties, it can be concluded that the composition of x = 0.085 is promising candidate material for lead-...

In this study, lead-free Sb substituted (Na0.525K0.4425Li0.0375)(Nb0.9625Ta0.0375)O3 ceramics were synthesized by traditional solid state sintering process. The effects of Sb substitution on the dielectric and piezoelectric properties were investigated in order to develop excellent lead-free piezoelectric ceramics. The (Na0.525K0.4425Li0.0375)(Nb0.9625-xSbxTa0.0375)O3 ceramics with x = 0.065 showed excellent piezoelectric properties. The piezoelectric constant (d33), electromechanical coupling factor (kp), dielectric constant (ϵr) and density were optimized as 193 pC/N, 50.25%, 703 and 4.48 g/cm3, respectively.

Developing flexible/stretchable piezoelectric nanogenerators (PNGs) for powering various portable wearable electronic devices has attracted considerable attention. In this study, we investigate the effects of changing the degree of alignment and thermal annealing conditions on the mechanical properties and the performances of the polymer nanofiber PNGs. PNGs are fabricated with electrospun poly(vinylidenefluoride-cotrifluoroethylene) (P(VDF-TrFE)) nanofibers under various rolling and thermal annealing posttreatment conditions. Thermal annealing increases both the ferroelectric phase and the modulus of the nanofibers, and geometrically aligned nanofibers show anisotropic changes in modulus, stiffer in parallel direction stretching. The performances of PNGs fabricated under various conditions are compared, and the mechanism by which the mechanical properties are affected by the degree of alignment and thermal annealing is analyzed and discussed. The well-aligned and thermally treated PNG cells showed the increased power density value of 1.35 mW cm−3 which is twice of the pristine randomly oriented samples without thermal treatment. Also, the nanofibers maintained its alignment structure after 10,000 times cyclic 7% stretching test without any cracks.

In this study, an acoustic emission (AE) sensor using lead free (Na,K)NbO3 system ceramics was fabricated. Also, the signal detection circuit and temperature stability properties of the AE sensor were presented and investigated, respectively. Signal detection circuit consisted of the impedance converter, high-pass filter, the signal amplification circuit, and rectifying circuit. The signal converted by impedance converter was amplified by amplifier, and the amplified signal was converted and displayed from AC to DC through a rectifying circuit. The Δkp/kp 20°C shows the maximum value of −0.015 at 30°C. Also, the Δf r/f r 20°C shows the maximum value of 0.075 at 80°C. Taking into consideration the above excellent temperature stability, it is considered that the AE sensor is suitable for detecting the partial discharge of power facilities.

In this study, in order to develop the composition of lead-free piezoelectric ceramics, the dielectric and piezoelectric properties of (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 ceramics were investigated as a function of CuO addition. The X-rd diffraction patterns demonstrated that the manufactured ceramics possessed pure perovskite structure with rhombohedral symmetry. The composition ceramics added with 0.4mol% CuO achieved remarkable physical properties: density = 5.51 g/cm3, kp = 0.477, Qm = 198, ϵr = 4284, To-t = 40°C, Tc = 80°C and d33 = 462pC/N. The SEM images of the sample showed that a certain amount of CuO addition could improve the crystalline grain growth. The phase transition temperature orthorhombic-tetragonal (To-t) and tetragonal-cubic (Tc) were shifted downward with CuO addition. These results demonstrate that the ceramics added with 0.4 mol% CuO is an attractive candidate for lead-free haptic piezoelectric actuator application.

In this study, [Li0.04(Na0.54 + x K0.46)0.96](Nb0.81Ta0.15 Sb0.04)O3 ceramics were prepared by conventional solid-state sintering techniques. The XRD pattern of the ceramics in range of 2θ from 43° to 48° indicated that the specimens have tetragonal symmetry when x (Na) ≤ 0.005. The piezoelectric constant (d33 ), dielectric constant (ϵr ) and electromechanical coupling factor (k p) were improved by compensating the evaporation of Na and enhancing the sinterability. All the samples have high density, ranging from 4.72 to 4.77(g/cm3). The dielectric and piezoelectric properties were enhanced due to Na excess. As the result, in the composition with x = 0.005, excellent properties of density = 4.73(g/cm3), kp = 0.46, d33 = 279(pC/N) and g33 = 20.26(mV.m/N) were obtained, respectively, suitable for piezoelectric energy harvesting device.

In this study, in order to develop lead-free composition ceramics for piezoelectric devices, (1-x)[(Li0.04(Na0.56K0.44)0.96(Nb0.90Ta0.10)0.998Zn0.005O3]—xKNbO3 (x = 0–7.5 mol%) composition ceramics were fabricated by a conventional sintering technique. The influences of KNbO3 on the microstructure, the dielectric, ferroelectric and piezoelectric properties of the ceramics were investigated. The results of XRD patterns show that the structure of specimen exhibits a tetragonal structure. The SEM images indicate that the grain size increased with increasing the content of KNbO3 substitution. Optimum physical properties of piezoelectric constant d33 = 255 pC/N, electromechanical coupling factor kp = 0.4358, dielectric constant ϵr = 699, measured density (ρ) = 4.49 g/cm3 were obtained from the composition ceramic with x = 3 mol%. These results indicate that the (1−x)LNKNTZ-xKN ceramic is a promising lead-free candidate material for practical piezoelectric device applications.

In this paper, the effect of AgNbO3 on microstructure, dielectric and piezoelectric properties of [Li0.02(Na0.55K0.45)0.98][(Nb0.77Ta0.18Sb0.05)0.9976Cu0.006] (abbreviated as LNKNTSC) ceramics were investigated. AgNbO3 has attracted great interest due to the weak ferroelectric compound with a high Curie temperature (TC) of 360°C. Lead-free (1-x)LNKNTSC-xAgNbO3 (x = 0 ∼ 0.075) piezoelectric ceramics were prepared by conventional solid solution method. All specimens were sintered in air at 1100°C for 5 hour. The density of LNKNTSC-AgNbO3 ceramics indicated a tendency to increase with increasing AgNbO3 content. The maximum density of 4.97 g/cm3 was obtained at 7.5 mol% AgNbO3 substituted ceramics. Therefore, AgNbO3 doping was sufficiently effective in promoting the densification of the ceramics. The piezoelectric constant d33 and planar electromechanical coefficient kp were increased with increasing AgNbO3 content. In addition, the tetragonal-orthorhombic phase transition temperature (TO-T) did not change la...

In this study, to develop the optimal composition of ceramics for low loss piezoelectric actuator and ultrasonic motor applications, (K0.5Na0.5)(Nb0.97Sb0.03)O3 + 0.009 K5.4Cu1.3Ta10O29 + 0.1wt%Li2CO3 + xwt%Bi2O3(x = 0 ~ 0.9) lead-free piezoelectric ceramics with a fixed quantity of 0.009 K5.4Cu1.3Ta10O29 (abbreviated as KCT) were manufactured using the conventional solid-state solution processes. The effects of Bi2O3 addition on the dielectric and piezoelectric properties were then investigated. From the X-ray diffraction analysis result the specimens demonstrated orthorhombic symmetry when Bi2O3 was less 0.6 wt%, a pseudo-cubic phase appeared when Bi2O3 was 0.9 wt%. SEM images indicate that a small amount of Bi2O3 addition affect the microstructure. The piezoelectric properties of (K0.5Na0.5)(Nb0.97Sb0.03)O3 ceramics were greatly improved by a certain amount of Bi2O3 addition. Excellent properties of density = 4.54 g/cm3, relative densities = 98.5 %, k p = 0.468, Q m = 1,715 and d 33 = 183 pC/N were obtained with a composition of 0.3 wt% Bi2O3

Lead-free [(Na0.54K0.46)0.96Li0.04](Nb0.80Ta0.20)O3(abbreviated as NKL-NT) ceramics were synthesized by conventional solid state sintering method and the effect of Co substitution on the microstructure and piezoelectric properties were investigated. The crystal structure and microstructure were investigated by X-ray diffraction (XRD) and SEM images. The crystal structure exhibited the tetragonal structure at the composition ceramics less than 1 mol% Co. However, with increasing Co substitution from 1.5 to 2.0 mol%, the ceramics showed morphotropic phase boundary (MPB) and the crystal structure of the ceramic possessed orthorhombic structure at 3 mol% Co. The grain size was increased with increasing of Co contents. The phase transition temperature tetragonal-cubic(TC) and orthorhombic-tetragonal(TO-T) were shifted to downward and upward with increasing Co contents, respectively. The high piezoelectric properties of d33 = 259[pC/N], kp = 0.43 and Qm = 109 were obtained from the 1.5 mol% Co substituted ceramics sintered at 1060 °C for 5 h.

In this study, in order to develop lead-free composition ceramics for piezoelectric actuator, (Na,K)(Nb,Sb)O3 ceramics modified with LiTaO3 were prepared by a conventional mixed oxide method. The influences of LiTaO3 on the microstructure, dielectric, ferroelectric, and piezoelectric properties were investigated. All the specimens showed a pure perovskite phase and no secondary phase could be confirmed from the XRD patterns. The SEM images indicate that the grain size increased with increasing the content of LiTaO3-substitution. Excellent physical properties of piezoelectric constant (d33) = 280 pC/N, electromechanical coupling factor (kp) = 0.534, dielectric constant (ϵr) = 980, and density (ρ) = 4.50 g/cm3 were obtained from the composition ceramic with x (LiTaO3) = 0.0375. These results indicate that the composition ceramic is a promising lead-free piezoelectric material for actuator applications.

In this study, Acoustic Emission (abbreviated as AE) sensor was fabricated using (Na,K,Li)(Nb,Ta,Zn)O3 system ceramics using thickness-shear-mode. The thickness-shear-mode piezoelectric device with the size of 8 × 6× 8 mm3 was determined from the result of ATILA simulation. Planar electromechanical coupling factor kp, piezoelectric constant d33 and g33 of (Na,K,Li)(Nb,Ta,Zn)O3 system ceramics showed the excellent values of 0.4366, 261[pC/N], and 40.11[×10−3 Vm/N], respectively, suitable for AE sensor device application. Thickness-shear-mode electromechanical coupling factor k15 showed 0.46 at the specimen size of 8 × 6× 8 mm3. The peak sensitivity and frequency of lead free type AE sensor showed 75.61 [dB] at 68.62 [kHz].

In this study, lead free (K0.5Na0.5)(Nb0.94Sb0.04)O3 + 1.2 mol% K4CuNb8O23 + x mol%La2O3 ceramics were prepared by conventional solid-state sintering method. The effect of La2O3 on the crystal stru...

In this study, in order to develop the composition ceramics for low loss multilayer piezoelectric devices for energy harvesting using strong vibration, Pb(Zn1/2W1/2)O3-Pb(Mn1/3Nb2/3)O3-Pb(Zr0.48Ti0.52)]O3 (abbreviated as PZW-PMN-PZT) ceramics were fabricated according to the amount of PZW substitution, using two-stage calcination method and conventional mixed oxide process. And also, their dielectric and piezoelectric properties were investigated. PZW substistution improved all the piezoelectric and dielectric characteristics due to the increase of sinterability. Crystal structure showed tetragonal phase without secondary phase. The piezoelectric constants values of d33 and g33 have to possess higher values as far as possible for the applications as energy harvesting piezoelectric devices using strong vibration. In this experiment, 5mol% PZW substituted specimen sintered at 930°C showed a maximum value of density = 7.905g/cm3, kp = 0.585, d33 = 351pC/N, g33 = 25.3 10−3 Vm/N and Qm = 1,254, respectively, f...

In this paper, ultrasonic nozzle and its driving circuit were manufactured. And then, their electrical properties were investigated. Ultrasonic nozzle using multilayer ring-type piezoelectric ceramics was fabricated by Pb[(Mn1/3Nb2/3)0.02(Ni1/3Nb2/3)0.12(Zr0.50Ti0.50)0.86]O3 (abbreviated as PMN-PNN-PZT) composition which have excellent piezoelectric characteristics. The multilayer ring-type piezoelectric ceramics using pure Ag inner electrode was sintered at 900°C low temperatures. In order to drive ultrasonic nozzle, Pulse Width Modulation controller (abbreviated as PWM) of KA3525A was used. With increasing the input voltage of ultrasonic nozzle, average diameter of light oil droplet was increased up to 16V and then decreased. At the input voltage of 12 V, volume average diameter of light oil droplet showed the minimum value of 37.3 μm and also at the input voltage of 16V, volume average diameter of fuel oil droplet showed the maximum value of 51.3 μm.

In this study, in order to develop the composition ceramics for low temperature sintering multilayer piezoelectric actuator, Pb(Mn1 / 3Nb2 / 3)O3−Pb(Ni1 / 3Nb2 / 3)O3− Pb(Zr0.48Ti0.51)O3 (abbreviated as PMN-PNN-PZT) ceramics were fabricated using Li2CO3, Na2CO3 and ZnO as sintering aids and according to the Ball milling time. And also, their dielectric and piezoelectric properties were investigated. At the High Energy Ball Milling (HEBM) time of 9 h and sintering temperature of 900°C, density, electromechanical coupling coefficient (kp), mechanical quality factor (Qm), dielectric constant (ϵr) and piezoelectric constant (d33) of PMN-PNN-PZT ceramics showed the excellent values of 7.978 g/cm3, 0.57, 1239, 1451 and 395 pC/N, respectively for low temperature sintering multilayer piezoelectric device application.

In this study, in order to develop lead free piezoelectric ceramics which have excellent temperature stability and high sinteribility for low loss multilayer piezoelectric actuator application, (Na,K)(Nb,Sb)O3 ceramics were fabricated and their piezoelectric and dielectric properties were investigated as a function of the amount of CoO addition. CoO addition improved sinterability, electromechanical coupling factor kp, piezoelectric constant d33 and dielectric constant ϵr of the composition ceramics. At the 0.3 wt% CoO added composition, density, kp, d33, ϵr and phase transition temperature showed the optimum values of 4.30 [g/cm3], 0.41, 211 [pC/N], 751 and 155°C, respectively, for low loss multilayer piezoelectric actuator application.

In this study, DC-DC converter using the thickness–vibration-mode piezoelectric transformer for driving high brightness LED was manufactured and its driving properties were investigated. LED output voltage of DC 4.11 V which can be feasibly turned on was observed. At the time, driving frequency of 1.12 MHz was measured. When the high brightness LED was turned on for 40 min., the surface temperature of the piezoelectric transformer under 2.5 W input power showed the temperature rise of 17°C. Its temperature was saturated after 25 min. after turning on and driving frequency slightly decreased as the temperature of the piezoelectric transformer increased. The high brightness LED was stably turned on at the frequency of 1.12 MHz.

In this study, Pb(Sb1/2Nb1/2)O3-Pb(Mn1/3Nb2/3) O3-Pb(Zr0.49Ti0.51)O3 (abbreviated as PSN-PMN-PZT) composition ceramics was sintered at 1230∼1270°C for developing the composition for piezoelectric transformer. At the ceramic composition sintered at 1250°C, Density, electromechanical coupling factor (kp) and mechanical quality factor (Qm) showed the excellent values of 7.78[g/cm3], 0.59 and 1931, respectively, suitable for piezoelectric transformer application. The single layer Rosen-type piezoelectric transformers were also sintered at the sintering temperature of 1250°C and manufactured with the size of 48 × 10 × 2 mm3, respectively, using the composition ceramics. And then, their electrical properties were investigated according to the variations of frequency and load resistance. At the load resistance of 150 kΩ, the voltage step-up ratio of the transformers showed the maximum values at the vicinity of 68.4KHz. And also, at that load resistance, piezoelectric transformers showed the temperature ...

In this study, in order to develop compositions of ceramics suitable for piezoelectric actuator and ultrasonic vibrator applications using low temperature sintering, multilayer, PMN-PNN-PZT ceramics were fabricated using and as sintering aids. Their structural, piezoelectric and dielectric characteristics were investigated according to the Zr/Ti ratio. As the Zr/Ti ratio increased, the electromechanical coupling factor , and piezoelectric constant and the mechanical quality factor all increased with Zr/Ti ratio and then decreased after the ratio exceeded 50/50. At the ratio of Zr/Ti

In this study, lead-free 0.95(K0.5Na0.5)NbO3-0.05Li(Sb1 − x Nb x )O3 system ceramics were fabricated according to the amount of Nb substitution for Sb site of LiSbO3 ceramics and their dielectric and piezoelectric characteristics were investigated. With increasing the amount of Nb substitution, electromechanical coupling factor (kp), density and piezoelectric constant (d33) increased up to 1mol% Nb and decreased above 1mol% Nb. With increasing the amount of Nb substitution, dielectric constant linearly decreased and Curie temperature increased. At the 1mol% Nb substitution composition ceramics sintered at 1040°C, electromechanical coupling factor (kp), density, dielectric constant (er), piezoelectric constant (d33) and Curie temperature (Tc) showed the optimal value of 0.41, 4.35 g/cm3, 789, 206 pC/N and 395°C, respectively for piezoelectric device application.

The multilayer ring type piezoelectric vibrator was manufactured using low temperature sintering Pb(Mn1/3Nb2/3)O3-Pb(Ni1/3Nb2/3)O3-Pb(Zr0.50Ti0.50)O3 (abbreviate ed as PMN-PNN-PZT) piezoelectric ceramic added Na2CO3 and Li2CO3 as sintering aids. And then, ultrasonic nozzle was fabricated using the vibrator. The driving current and driving power of the ultrasonic nozzle showed the stable values as 260 mA and 8.1W after 10 min operation. No problems were occurred even under long time operation because the surface temperature of the ceramic actuator kept the maximum value of 26°C in the experiment.

In this study, in order to develop the composition ceramics for low loss multilayer piezoelectric actuator, 0.07Pb (Mn1/3Nb2/3) O3 −0.10Pb (Ni1/3Nb2/3) O3− 0.83Pb(Zr0.48Ti0.52) O3 (abbreviated as PMN-PNN-PZT) ceramics were fabricated using Li2CO3, Bi2O3 and CuO as sintering aids and according to variation of heating rate. And also, their dielectric and piezoelectric properties were investigated. At the heating rate of 700°C/h and sintering temperature of 900°C, density, electromechanical coupling coefficient (kp), mechanical quality factor (Qm), dielectric constant (e r ) and piezoelectric constant (d33) of PMN-PNN-PZT ceramics showed the excellent values of 7.67 g/cm3, 0.58, 1199, 1560 and 380 pC/N, respectively for low loss multilayer piezoelectric actuator application.

In this study, in order to develop the composition ceramics for low loss multilayer piezoelectric actuator application, (abbreviated as PZW-PMN-PZT)ceramics according to the amount of addition were fabricated using two-stage calcinations method. And also, their dielectric and piezoelectric properties were investigated. At the 0.2 wt% added PZW-PMN-PZT ceramics sintered at , density, electromechanical coupling factor , dielectric constant , piezoelectric constant and mechanical quality factor showed the optimum value of , 0.543, 1,392, 318.7 pC/N, 1,536, respectively for low loss multilayer ceramics actuator application.〹〰〰㜳

In this paper, ultrasonic nozzle and driving circuit were manufactured and their electrical properties were investigated. Ultrasonic nozzle was fabricated using Pb[(Sb1/2Nb1/2)0.035(Mn1/3Nb2/3)0.065(Zr0.49Ti0.51)0.90]O3+ 0.5wt%PbO (abbreviated as PSN-PMN-PZT) ceramics showing excellent piezoelectric characteristics. In order to drive ultrasonic nozzle, Pulse Width Modulation controller (abbreviated as PWM) of KA3525A was used. With increasing the input voltage of nozzle, average diameter of fuel oil droplet was increased up to 16 V and then decreased. At the input voltage of 12 V, volume average diameter of fuel oil droplet showed the minimum value of 37.3 μm and also at the input voltage of 16 V, volume average diameter of fuel oil droplet showed the maximum value of 51.3 μm.

Pb(Mn1/3Nb2/3)O3–Pb(Zn1/3Nb2/3)O3–Pb(Zr0.48Ti0.52)O3 (abbreviated as PMN–PZN–PZT) ceramics containing Li2CO3, Bi2O3 and CuO as sintering aids were fabricated using two-stage calcinations method in order to develop low temperature sintering ceramics for multilayer piezoelectric actuators. Their dielectric and piezoelectric properties were investigated according to the variation of sintering time. All the specimens sintered at 930°C for 60~150 min showed tetragonal phases without secondary phases. Electromechanical coupling factor (kp), dielectric constant (er) and piezoelectric constant (d33) increased with the increase of the sintering time. The mechanical quality factor (Qm) exhibited maximum of 1,815 with the increase of sintering time for 120 min and then slightly decreased. At the sintering temperature of 930°C and the sintering time of 120 min, the optimal values such as the density of 7.69 g/cm3, kp of 0.516, er of 1158, Qm of 1815, and d33 of 287 pC/N were found for multilayer piezoelectric actuators.

In this study, in order to develop low-temperature-sintering ceramics for multilayer piezoelectric actuator, Pb(Mg1/2W1/2)O3–Pb(Ni1/3Nb2/3)O3–Pb(Zr,Ti)O3 (abbreviated as PMW–PNN–PZT) ceramics were fabricated using Li2CO3 and CaCO3 as sintering aids and their dielectric and piezoelectric properties were investigated with the amount of Pb(Ni1/3Nb2/3)O3 (abbreviated as PNN) substitution. PMW–PNN–PZT composition ceramics could be sintered up to 870°C by adding sintering aids. At the sintering temperature of 900°C, electromechanical coupling factor (k p), piezoelectric constant (d 33) and Curie temperature (Tc) in the composition ceramics with 9 ;mol% PNN substitution showed the optimal value of 0.64 517 ;pC/N and 317°C, respectively for multilayer actuator application.

In this study, in order to develop the composition ceramics for multilayer ceramic for ultrasonic nozzle and ultrasonic actuator application, Pb(Mn1/3Sb2/3)O3 (abbreviated as PMS) substituted Pb(Ni1/3Nb2/3)O3–Pb(Zr,Ti)O3 (abbreviated as PNN-PZT) ceramics were fabricated using two-stage calcinations method and Li2CO3, Na2CO3 and ZnO as sintering aids, and their piezoelectric and dielectric characteristics were investigated. With the increase of the amount of PMS substitution, electromechanical coupling factor (k p), and mechanical quality factor (Q m) of specimens showed the maximum value at 3 mol% substituted specimen while dielectric constant (ɛ r) was decreased. At the sintering temperature of 900 °C, the density, ɛ r, k p, and Q m of 3 mol% PMS substituted PNN-PZT composition ceramics showed the optimal values of 7.92 [g/cm3], 959, 0.584, and 1003, respectively, for low loss multilayer piezoelectric actuator application.

PMN-PNN-PZT ceramics doped with sintering aids such as Li2CO3 and Na2CO3 were fabricated using two-stage calcination method and their structural and piezoelectric properties were investigated according to the 1st calcination temperature in order to develop ceramic composition for low loss and low temperature sintering multilayer piezoelectric actuator. The coulombite phase was successfully synthesized at 1050°C, resulting in increase of perovskite amount of PMN-PNN-PZT ceramics. At the calcination temperature of 1050°C and sintering temperature of 900°C, density, electromechanical coupling factor (kp), mechanical quality factor (Qm), dielectric constant (er) and piezoelectric constant (d33) of PMN-PNN-PZT ceramics showed the optimum values of 7.885 g/cm3, 0.609, 1088, 1168 and 356 pC/N, respectively.