O3 Piezoelectric Ceramics Research Articles

Reversible photochromism and photoluminescence modulation in (K,Na)NbO3‐based ceramics via oxygen vacancy regulation

AbstractMost of the optical behaviors in photoelectric multifunctional ceramics strongly depend on the addition of rare‐earth elements. However, the limited species of rare‐earth cations available as luminescence centers restrict the further development of photoelectric devices. Additionally, introducing the large atomic‐radii elements usually dramatically deteriorates the piezoelectric properties. Herein, the novel photochromism and luminescence modulation properties have been realized in CuO‐doped [(K0.43Na0.57)0.94Li0.06][(Nb0.94Sb0.06)0.95Ta0.05]O3 (KNLNST) piezoelectric ceramics which show intense sensitivity to visible‐light irradiation. As a strategy for regulating oxygen vacancy concentrations in piezoelectric ceramics, different CuO amounts are doped to generate color centers for photochromism. The photoluminescence phenomenon exhibiting green emission under 375 nm excitation is observed in KNLNST piezoelectric ceramics, which is most commonly realized via rare‐earth doping in luminescent materials. KNLNST–0.3CuO ceramics with the highest oxygen vacancy concentration achieve a reversible luminescence modulation of 46.9% by altering light irradiation and thermal stimulus. Moreover, a hand‐rewritable optical information test demonstrates exceptional reproducibility and fatigue durability. This research displays the controllable photochromism and luminescence behaviors in ceramics via regulating oxygen vacancy concentration by CuO “hard” doping. The lead‐free high performance photoelectric ceramics fulfill the demands of potential applications in anti‐counterfeiting and optical storage devices.

Revealing multiphase coexistence of R-O-T phases in BaTiO3-CaTiO3-BaSnO3 electroceramics for energy harvesting and storage response with piezo actuation

The (Ba1-xCax)(SnyTi1-y)O3 piezoelectric ceramics (where x=0.016, y=0.024; x=0.032, y=0.048; x=0.048, y=0.072; x=0.064, y=0.096; x=0.08, y=0.12) were designed by conventional solid state reaction method. The crystal structure for the composition of x=0.064 and y=0.096 (abbreviated as BCST-4) possesses the coexistence of non-centrosymmetric rhombohedral-orthorhombic-tetragonal (R-O-T) tri-lattice symmetries at room temperature, as demonstrated by the structural Rietveld refinement, Raman analysis, and temperature dependence of dielectric study. Because of the R-O-T multiphase coexistence, BCST-4 possesses a superior electromechanical and piezoelectric property viz. kp ∼ 0.45, strain ∼ 0.100 %, d33* ∼ 649 pm/V, and an improved d33 ∼ 452 pC/N, which is comparable to commercially available soft PZT ceramics (d33 ⁓ 370 pC/N). For BCST-4 ceramics, an exceptional electrostriction coefficient Q33 ∼ 0.0434 m4/C2 value was attained. The intrinsic piezo-actuation DC strain was observed to be 130 microstrain (με) and 188 με with ε33 and ε31 modes respectively. The BCST-4 ceramic exhibits a maximum output power of 1.03 mW, a power density of 13.5 µW/mm3, a maximum output current of 88 µA, and an open circuit voltage Vpp of 28 V which successfully glowed ‘SPPU’ panel having 40 red commercial light-emitting diodes (LEDs). The energy storage study reveals that BCST-4 ceramics exhibit a maximum energy storage density (Wrec) of 165.87 mJ/cm3 with efficiency (ƞ) 68.00 %. Therefore, the improvement in electrostriction coefficient, piezoelectric charge coefficient, and energy storage response indicates that BCST-4 ceramic has the potential for actuator, energy harvesting, and energy storage applications.

Enhancing the piezoelectric performance of novel PZT-PMS-PSN piezoelectric ceramics by fine-tuning the monoclinic phase

The enhanced high-power performance of 0.93 Pb(Zr1-xTix)O3-0.05 Pb(Mn1/3Sb2/3)O3-0.02 Pb(Sc1/2Nb1/2)O3 (x = 0.48, 0.50, 0.52, 0.54, 0.56) piezoelectric ceramics (PZT-PMS-PSN) has been achieved with notable improvement in the piezoelectric coefficient (d33). The presence of the monoclinic phase (Cc) has led to an increase in d33 from 214 pC N−1 to 315 pC N−1. Therefore, the composition 0.93 Pb(Zr0.48Ti0.52)O3-0.05 Pb(Mn1/3Sb2/3)O3-0.02 Pb(Sc1/2Nb1/2)O3 exhibits excellent mechanical and electrical parameters: a d33 value of 315 pC N−1, a high mechanical quality factor of 1578, an electromechanical coupling factor kp of 52 %, and a low dielectric loss tanδ of only 0.288 %. Additionally, this ceramic exhibits a significantly high Curie temperature (Tc), reaching up to 328 °C which stabilizes its ferroelectric phase. Moreover, the phase transition of PZT-PMS-PSN ceramics from rhombohedral to tetragonal phase was investigated by X-ray diffraction, Raman scattering, Piezo-response force microscopy.

Tracking high-performance Pb(Ni1/3Sb2/3)O3–Pb(Zr0.48Ti0.52)O3 piezoelectric ceramics near morphotropic phase boundary

Tracking high-performance Pb(Ni1/3Sb2/3)O3–Pb(Zr0.48Ti0.52)O3 piezoelectric ceramics near morphotropic phase boundary

Ultra-high strain in Bi0.5(Na0.41K0.09)TiO3 Pb-free piezoelectric ceramics modified by Sr(Hf0.5Sb0.4)O3

The lead-free piezoelectric ceramics used in piezoelectric actuators have attracted extensive attention owing to their substantial electric-field-induced strain. In this study, The (1-x)Bi0.5(Na0.41K0.09)TiO3-xSr(Hf0.5Sb0.4)O3 (BNKT-xSHS) piezoelectric ceramics were synthesized using the conventional solid-state reaction method. The impact of SHS substitution on the microstructure and electrical properties was systematically explored. Among them, the BNKT-0.015SHS sample, featuring ergodic relaxor states, demonstrates a high piezoelectric strain coefficient (d33*) of 785 p.m./V under a low electric field of 50 kV/cm(Strain = 0.392 %). It exhibits a repeatable strain value of 0.47 % under an 80 kV/cm electric field(d33* = 590 p.m./V). Moreover, the strain values remain around 0.4 % between room temperature and 100 °C, with variations within 90 %. The heightened repeatable strain response is considered to be linked to the electric field-induced reversible phase transition occurring within the ergodic relaxor state. The higher strain temperature stability is ascribed to the coexistence of quadrilateral polar nanoregions and rhombic polydomain nanoregions. This study provides an effective example for achieving significant strain responses, presenting a feasible candidate material for applications in piezoelectric actuators.

The Effect of Bi0.5Li0.5ZrO3-SrSnO3 Composite Doping on the Construction of Polymorphic Phase Boundaries and Enhanced Electrical Properties of K0.45Na0.55Nb0.965Sb0.035O3 Piezoelectric Ceramics

In this experiment, a new lead-free piezoelectric ceramics (1−x)K0.45Na0.55Nb0.965Sb0.035O3−x(0.9Bi0.5Li0.5ZrO3−0.1SrSnO3) were prepared by the conventional solid-phase method, and the effects of the doping amount of 0.9Bi0.5Li0.5ZrO3−0.1SrSnO3 on the K0.45Na0.55Nb0.965Sb0.035O3 ceramics on the crystal structure, microstructure, microscopic structure and electrical properties. All the doping ions entered the KNN lattice and formed a dense solid solution with a single-phase structure, and the phase structure of the ceramics coexisted from orthorhombic (O) to orthorhombic-tetragonal (O-T) phases in the range of 0 ≤ x ≤ 0.03, and transitioned to rhombohedral-tetragonal (R-T) phase coexistence when 0.035 ≤ x ≤ 0.05. The electrical properties of the ceramics were analyzed and the polymorphic phase boundary (PPB) region was obtained at x = 0.035 and had the best overall properties: d 33 = 324pC/N, k p = 49%, ε r = 1479, tanδ = 3.21%, P r = 31.98 μC/cm2, E c = 16.83 kV cm−1 and T C = 293°C. By The microstructural analysis of the ceramics showed that the appropriate amount of compound doping of the second element enhances the denseness of the ceramics as well as makes the grains uniformly distributed. These results indicate that the ceramics of this system have great prospects for future applications in the field of lead-free piezoelectric ceramics.

Effects of heterovalent ions doping-induced oxygen octahedral distortion and defect chemical change on piezoelectric characteristics and thermal stability of PHT-PIN ceramics

Electromechanical devices require functional materials possessing excellent piezoelectric properties, good thermal stability, and high electromechanical coupling coefficients. To modulate the piezoelectric, dielectric, and electromechanical characteristics of 0.89Pb(Hf0.47Ti0.53)O3-0.11Pb(In1/2Nb1/2)O3 (PHT-PIN) piezoelectric ceramics, heterovalent ions of lithium (Li) and tungsten (W) were doped through a traditional solid-phase reaction approach. On the one hand, large lattice distortions caused by the doped W6+ resulted in the shortening of BO bonds while an increase in the local displacement of B-site ions. Moreover, a mismatch occurred for the oxygen octahedral dimensions, and a subsequent disruption of the long-ranged ordered ferroelectric domains was observed, which resulted in the formation of microdomains. On the other hand, the changes in the concentration of oxygen vacancy defects induced by the Li and W doping inside the ceramic were comprehensively analyzed. The decrease in the concentration of oxygen vacancies was found to be accompanied by the enhancement of piezoelectric properties of the material. Excellent comprehensive performance (piezoelectric coefficient d33 = 655 pC N−1, Curie temperature Tc = 321.1 °C, dielectric constantεr = 3352.31, electromechanical coupling coefficient kp = 0.67, and residual polarization strength Pr = 55 μC cm−2) was obtained for 0.2 mol % doping amount of Li+ and W6+ ions. This work, therefore, proposes a novel strategy for the origin of piezoelectric properties and inspires doping of other heterovalent ions to improve the piezoelectric properties of ceramics. It further promotes the development of Pb-based piezoelectric ceramics for electromechanical devices that can efficiently operate under high-temperature environments.

Ultrahigh strain in PZ-PT-BNT piezoelectric ceramic

Low strain limits the further application of Pb(Zr,Ti)O3 (PZT) piezoelectric ceramics in actuators. Herein, a ternary piezoelectric ceramic xPbTiO3-(0.95-x)PbZrO3-0.05(Bi0.5Na0.5)TiO3 (xPT-PZ-BNT) is proposed and prepared by solid-state method to improve the strain characteristics. Results indicate that a biased electric field is intentionally constructed by defects arising from the incorporation of BNT into PZ-PT ceramic, which promotes non-180° domains to restore to initial states, thereby contributing to the increase in strain. Moreover, the electric domain configuration is efficiently modified by adjusting the component proportion in xPT-PZ-BNT ceramics, in which the 0.42 PT-PZ-BNT presents short and broad domains with fast response to external electric field. Rayleigh analysis indicates that the strain contributed by domain switching is dominant in PT-PZ-BNT ceramics under a high electric field. Consequently, a large strain of 0.4% is achieved in 0.42 PT-PZ-BNT ceramic with the variation less than 10% in the temperature range of 25∼175 °C. This study not only deeply analyzes the effect of domain configuration on the strain for PZT piezoelectric ceramics, but also demonstrates an effective approach to increase the strain through constructing internal biased electric field and regulating domain configuration.

Effect of crystallization annealing on magnetoelectric properties of amorphous ferromagnet – piezoelectric ceramics – amorphous ferromagnet three-layer composites

Magnetoelectric properties of three-layer symmetrical composites consisting of two layers of Fe0.45Co0.45Zr0.1 amorphous ferromagnetic alloy and a layer of PbZr0.53Ti0.47O3 piezoelectric ceramics were studied. It was revealed that the magnetoelectric coefficients of the composites pass through a maximum depending on a frequency of the alternative magnetic field and strength of the bias magnetic field and decrease as a volume fraction of the piezoelectric and temperature increase. Regularities revealed in the present work are explained in terms of a theory of the magnetoelectric effect. After crystallization annealing in a vacuum, we observed a deterioration of the magnetoelectric properties of the composites which correlates with a weakening of the piezomagnetic properties of Fe0.45Co0.45Zr0.1 and is related to an increase in a force of interaction between domain walls and defects in Fe0.45Co0.45Zr0.1.

Effects of CuO additive on properties of high-performance (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 piezoceramics obtained by vat photopolymerization

Lead-free (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 (BCZT) piezoelectric ceramics are ideal materials for the preparation of piezoelectric ceramic devices. However, pure BCZT ceramics have the problems of high sintering temperature and unsatisfactory Curie temperature. Besides, piezoelectric ceramic devices with complex structures are difficult to fabricate with conventional processing methods. In this paper, we prepared BCZT ceramics with CuO additions of 0, 0.5, 1.0, 1.5, and 2.0 mol% based on vat photopolymerization, and investigated effects of CuO additive on their various properties. The appropriate addition of CuO greatly improved the piezoelectric properties and lowered the sintering temperature by 100 °C. With increasing CuO content, it was found that the phase composition shifted from an orthogonal phase to the coexistence of orthogonal and tetragonal phases. BCZT-1.5 mol%CuO sintered at 1400 °C exhibited the best performance: d33 = 525 pC/N，g33 = 13.7 × 10−3 Vm/N，εr = 4323，tan δ = 0.012，Pr = 14.66 μC/cm2，Ec = 2.42 kV/cm. In addition, when the energy harvesting performance of BCZT-1.5 mol%CuO with complex structures prepared by vat photopolymerization was tested, the short circuit current (Isc) and open circuit voltage (Voc) of BCZT-1.5 mol% CuO ceramics were ∼13.0 pA and ∼11.0 mV, respectively, which exhibited better energy harvesting capability than the pure BCZT ceramics. These results suggest that the performance of BCZT ceramics can be significantly enhanced with CuO additive and verify the feasibility of vat photopolymerization forming high-performance piezoelectric ceramics with complex structures.

Magnetoelectric effect in two-layer heterogeneous systems based on Mn0.4Zn0.6Fe2O4 ferrite and PbZr0.53Ti0.47O3/epoxy particulate piezoelectric composites

Comparison of magnetoelectric properties of two-layer heterogeneous systems based on Mn0.4Zn0.6Fe2O4 ferrite and PbZr0.53Ti0.47O3 piezoelectric ceramics with ratio of the piezoelectric coefficient to the permittivity pd31/pɛ33 = 0.06 and two-layer heterogeneous systems based on Mn0.4Zn0.6Fe2O4 ferrite and PbZr0.53Ti0.47O3/epoxy piezoelectric composite with pd31/pɛ33 = 0.07 − 0.09 was carried out. It was revealed that the magnetoelectric properties of the heterogeneous systems enhance with an increase in pd31/pɛ33 for a piezoelectric.

Enhanced high‐power performance of Fe‐doped PZMNZT piezoelectric ceramics

AbstractHigh‐power piezoelectric ceramics are typically driven to output vibration velocity (v0) under high AC electric fields. Herein, the Fe2O3 doped 0.125 Pb(Zn1/3Nb2/3) O3–0.075 Pb(Mn1/3Nb2/3)O3–0.8 Pb(Zr0.48Ti0.52)O3(PZMNZT–xFe; x = 0.05–0.35) piezoelectric ceramics were prepared to enhance v0, and the favorable comprehensive electrical properties, such as d33 = 315 pC/N, Qm = 1738, kp = 0.58, kt = 0.48, εr = 1156, tan δ = 0.4%, and Tc = 320°C, were achieved in the PZMNZT–0.15Fe ceramic. Most importantly, the PZMNZT–0.15Fe ceramic presented a reliable v0 of 0.90 m/s, which was 2.25 times of the commercial PZT4 ceramic (∼0.40 m/s). The excellent high‐power performance should be attributed to ordering functional elements such as crystal grains and ferroelectric domains. Overall, this work reveals that the PZMNZT–0.15Fe ceramic is competitive for high‐power applications.

Poling above the Curie temperature driven large enhancement in piezoelectric performance of Mn doped PZT-based piezoceramics

The enhancement of piezoelectricity is usually in sacrifice of Curie temperature, which in turn limits its working temperature range. It is well known that there are some trade-off among the various performance parameters of most piezoelectric ceramics, and it is still difficult to achieve synergistic improvement in multiple parameters. Here, it is reported that the piezoelectric coefficient d33 of a 0.6 mol% Mn-doped Pb(Sb0.5Nb0.5)0.02Zr0.51Ti0.47O3 piezoelectric ceramics is increased to 436 pC N−1, and its electro-strain can reach 0.16% (d33* = 800 pm/V) at 2 kV mm− 1 by high-temperature poling, whose Curie temperature can still keep at 347 ℃. The features of "hard" piezoelectric ceramics such as low dielectric loss (tgδ = 0.23%) and high mechanical quality factor (Qm = 546) are also preserved. Through structural characterization, combined with the theoretical results of phase field simulation, it is shown that its excellent piezoelectric performance originates from the highly oriented domain structure and small domain size after high temperature poling. On the other hand, the valence state transition of Mn3+ ions during high-temperature poling increases the defect vacancies and lattice distortion in ceramics, which keeps the acceptor-doped characteristic of the ceramics.

Polarization response and thermally stimulated depolarization currents of the modified (Ba,Ca) (Zr,Ti)O3 piezoelectric ceramics

Polarization response and defect mechanism of the (Ba,Ca) (Zr,Ti)O3 piezoelectric ceramics by doping modification were intensively investigated. The Al-doping leads to the reduced piezoelectric polarization responses, but optimizes fatigue resistance and the quality factor, showing the acceptor characteristics. A way to test thermally stimulated depolarization currents (TSDC) is utilized to distinguish the role of defect dipole from oxygen vacancy and uncover the intrinsic reason of improving cyclic fatigue behavior. It has been confirmed that the improvement of fatigue behavior can be attributed to the formation of oxygen vacancies by Al doping. The present study gives a promising method to reveal the origin of piezoelectric characteristics based on defect configuration in advanced dielectrics.

The grain growth mechanisms for 0.8(Bi,Na)TiO3-0.2(Sr,Ti)O3 ceramics prepared using a two-step sintering process

ABSTRACT In this study, lead-free 0.8(Bi,Na)TiO3-0.2(Sr,Ti)O3 piezoelectric ceramics were prepared using a two-step sintering process to analyze their sintering mechanisms. Two-step sintering process has benefits of being able to be conducted at lower temperatures than conventional sintering process, but the complicated sintering mechanisms involved in this process have not been yet fully investigated. Therefore, in the present study, two-step sintering mechanism for lead-free piezoelectric ceramics was analyzed by estimating the activation energy required depending on the sintering conditions. Using the two-step sintering process, the piezoelectric charge and electromechanical coupling coefficients improved from 146 pC/N and 0.347 to 163 pC/N and 0.377, respectively. By comparing the grain-growth mechanisms for the conventional and two-step sintering processes, it appeared that the sintering mechanisms differed. By introducing the two-step sintering process, piezoelectric ceramics with improved piezoelectric charge and electromechanical coupling coefficients were produced.

Anisotropic Piezoelectric Properties of Porous (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 Ceramics with Oriented Pores through TBA-Based Freeze-Casting Method.

Porous (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCZT) piezoelectric ceramics with an oriented directional hole structure were prepared by using the tertbutyl alcohol (TBA)-based freeze-casting method. The influences of sintering temperatures on the microstructure and piezoelectric properties of porous BCZT ceramics were investigated both perpendicular and parallel to the freezing direction. With the increase in sintering temperatures and the porosities decreased from 58% to 42%, the compressive strength increased from 14.0 MPa to 25.0 MPa. In addition, the d33 value of 407 pC/N for the sample sintered at 1400 °C was obtained parallel to the freezing direction, which was 1.40 times that of the other direction.

Ultrahigh electrostrains of lead-free (Ba,Ca)(Ti,Zr)O3 piezoelectric ceramics via defect engineering

Ultrahigh electrostrains of lead-free (Ba,Ca)(Ti,Zr)O3 piezoelectric ceramics via defect engineering

Ultrasonic transducer with BiScO3-PbTiO3-based ceramics of operating temperature over 400°C

Ultrasonic transducers are widely employed in many fields such as non-destructive testing (NDT), petrochemical refineries, aerospace field, etc., in which high temperature ultrasonic transducers are necessary because many measurements must be done at elevated temperature. In this work, 4.5 MHz high temperature ultrasonic transducers with delay line were designed and fabricated based on BiScO3-Pb(Ti0.99Zn0.01)O3 (BS-0.01PZnT) piezoelectric ceramics possessing excellent temperature stability and high Curie temperature. The experimental results revealed that −6 dB bandwidth and the center frequency of high temperature ultrasonic transducers are around 129% and 4.5 MHz, respectively, which are almost stable from room temperature to 400 °C. The peak-to-peak values (Vpp) is as large as 1.5 V at RT, indicating very high sensitivity. More importantly, the ultrasonic transducers with customized BS-0.01PZnT ceramics can work reliably at high temperature of 380 °C and 450 °C by in-situ measurement at elevated temperatures. This work verifies the great potential application values of ultrasonic transducers with BS-0.01PZnT ceramics in high temperature applications.

Enhanced electrical and energy harvesting performances of lead-free BMT modified BNT piezoelectric ceramics

ABSTRACT Lead-free (1-x) (Bi0.5Na0.5)TiO3-xBi(Mg0.5Ti0.5)O3 or (1-x)BNT-xBMT (x = 0–0.20) piezoelectric ceramics have been investigated for phase evolution, microstructure, dielectric, ferroelectric, piezoelectric, electric field-induced strain, energy storage density, energy harvesting, and magnetic properties. All compositions exhibited high density sintered ceramics (~ 6.13–6.30 g/cm3). With increasing modifier content, the crystal structure changed from rhombohedral to cubic phase. When BMT content was added, the grain size and Tm were found to increase. The x = 0.05 ceramic showed good piezoelectric (low-field d33 = 159 pC/N) and ferroelectric (Pr = 23.84 µC/cm2, Ec = 34.41 kV/cm) properties. The BMT additive also produced an improvement in electric field-induced strain, energy storage efficiency, and magnetic properties. The highest piezoelectric voltage constant (g33 = 26.29 × 10−3 Vm/N) and the off-resonance figure of merit (FoM) for energy harvesting (~ 4.18 pm2/N) were also obtained for the x = 0.05 ceramic, which was ~ 3.4 times (240%) as compared to the pure BNT ceramic. This suggested that the ceramic has a potential to be one of the promising lead-free piezoelectric candidates for further use in piezoelectric energy harvesting applications.

Effects of coupling ability of dopants on NbO6 vibration and piezoelectric properties of KNN lead-free ceramics

In the work, the lead-free (K0.5Na0.5)NbO3, (K0.5Na0.5)0.95Li/Ag0.05NbO3 and (K0.5Na0.5)Nb0.95Sb/Ta0.05O3 piezoelectric ceramics were prepared by a solid-state method. The relationships between the coupling ability of the dopants and NbO6 vibration of the ceramics were investigated. The intensity of NbO6 vibration is ascribed to the dopant's radius. However, the distortion of NbO6 is independent of the vibration. The dopants with high coupling ability (i.e., Ag and Ta) give rise to more severe distortion of NbO6, resulting in bigger piezoelectric enhancement for KNN–Ag and KNN–Ta. Furthermore, the NbO6 vibration plays an indispensable role in ferroelectric phase transition while the c/a accounts for the Curie temperature.