TiO3-based Ceramics Research Articles

Correlation between depolarization temperature and lattice distortion in quenched (Bi1/2Na1/2)TiO3-based ceramics

(Bi1/2Na1/2)TiO3 (BNT) is one of the candidates for lead-free piezoelectric ceramics. Recently, we found that the depolarization temperature Td of BNT could be increased by approximately 40 °C–80 °C with a quenching treatment after the sintering. To elucidate the mechanism, high-energy synchrotron X-ray powder diffraction data were collected in SPring-8 to analyze their crystal structures in detail. In the case of a quenched BNT-based sample, Bi ions displaced more to the off-center position of the A-site in a perovskite structure with a more ordered structure. The increase in rhombohedral distortion then affects the Td elevation in the quenched sample.

Enhanced piezoelectric properties and depolarization temperature in NBT-based ceramics by doping BT nanowires

(Na0.5Bi0.5)TiO3-(K0.5Bi0.5)TiO3–BaTiO3 ternary ceramic exhibits excellent piezoelectric properties, but its depolarization temperature is a longstanding obstacle for their practical applications. The improvement of depolarization temperature of (Na0.5Bi0.5)TiO3-based ceramics is usually companied by deterioration of piezoelectric properties. In this study, we use BaTiO3 nanowires to replace BaTiO3 solution in off-MPB 0.88(Na0.5Bi0.5)TiO3-0.06(K0.5Bi0.5)TiO3-0.06BaTiO3 ceramic. A narrower peak in tanδ-T curves is obtained and the depolarization temperature Td increased from 95 °C to 133 °C after BaTiO3 nanowires substituting for BaTiO3 solution. The promotion of Td is thought to be associated with that the BaTiO3 nanowires may pin the domain wall and suppress the dispersion of temperature induced FE-RE (AFE) phase transition. Meanwhile, the piezoelectric constant d33 enhanced from 105 to 192 pC/N simultaneously due to the formation of MPB phase structure and high ε33Pr value. The results proposed that the piezoelectric properties and depolarization temperature can be simultaneously improved in (Na0.5Bi0.5)TiO3-based ceramics by doping BaTiO3 nanowires into appropriate basic materials.

Large energy density with excellent stability in fine-grained (Bi0.5Na0.5)TiO3-based lead-free ceramics

In this work, fine-grained (0.95-x)(Bi0.5Na0.5)TiO3-0.05BaTiO3-xBi(Zn2/3Nb1/3)O3 (abbreviated as BNT-BT-xBZN, x = 0∼0.20) lead-free ceramics are successfully prepared, showing a high energy storage performance. The addition of BZN results in decreased grain size, enhanced breakdown strength and stronger relaxor behavior with polar nanoregions. Slimmer P-E loops are thereby achieved, leading to the improvement of energy density and efficiency. As a result, a high WD of ∼2.83 J/cm3 is achieved under a relatively low electric field of 18 kV/mm in the x = 0.125 ceramic with submicron-sized grains (∼0.4 μm). The WD value is larger than that of x = 0 ceramic by ∼800%. Furthermore, the x = 0.125 ceramic possesses excellent frequency stability and strong fatigue endurance. The BNT-BT-xBZN lead-free ceramics show promising potential for application in high energy density ceramic capacitors.

Direct observation of the stress-induced domain structure in lead-free (Na1/2Bi1/2)TiO3-based ceramics

In this work, the creep behavior of (Na1/2Bi1/2)TiO3-0.07BaTiO3 was characterized as a function of bias stress up to −500 MPa, revealing the time-dependence of the stress-induced relaxor-to-ferroelectric long-range order transformation. Creep strain was observed across a range of applied compressive stress levels, in particular at stresses approximately 50% above the critical coercive stress, indicating the significant time-dependence of the transformation on the long-range ferroelectric order. The macroscopic behavior is discussed in conjunction with ex situ piezoresponse force microscopy measurements that directly show the formation of ferroelectric domains in mechanically loaded relaxor ferroelectrics.

Effect of Mn-doping on dielectric and energy storage properties of (Pb0.91La0.06)(Zr0.96Ti0.04)O3 antiferroelectric ceramics

Bulk ceramics with high recoverable energy density (Wre) and energy efficiency (η) play a critical role in the development of pulsed power systems for miniaturization and lightweight. The orthorhombic phase (Pb,La)(Zr,Ti)O3-based antiferroelectric (AFE) ceramics have been regarded as one of the most promising candidates for pulsed power system applications due to their relatively high energy storage density and efficiency. However, the main drawback of orthorhombic phase (Pb,La)(Zr,Ti)O3-based AFE ceramics is relatively low dielectric breakdown strengthen (DBS), which has always restricted the improvement of energy storage density. In this study, an effectively method to increase DBS by the introduction of Mn has been proposed. The relative density of orthorhombic phase (Pb0.91La0.06)(Zr0.96Ti0.04)O3 (PLZT) ceramics was improved by Mn-doping. And the introduction of Mn can decrease the tolerance factor (t) of PLZT ceramics because the radius of Mn2+ is larger than that of B-site Zr4+/Ti4+, and thus enhancing antiferroelectricity. Meanwhile, the effects of Mn-doping on the phase structure, microstructure and dielectric properties of PLZT ceramics have been studied thoroughly in this study. It is found that the highest Wre of 7.65 J/cm3 is obtained at 1.0 mol% Mn-doped PLZT ceramic, which is obviously larger than that of undoped PLZT ceramic (5.71 J/cm3). These results suggest that the Mn-doped PLZT ceramics are potential energy storage materials in pulsed power systems.

In-situ temperature stability of a piezoelectric accelerometer based on (Bi, Na, K, Li)TiO3 ceramics

This work investigated the in-situ temperature stability of 0.76(Bi0.5Na0.5)TiO3-0.04(Bi0.5Li0.5)TiO3-0.2(Bi0.5K0.5)TiO3 piezoceramics and a compression-mode accelerometer composed of these materials. The temperature-dependent charge sensitivity of the accelerometer was governed by the small-signal piezoelectric coefficient d33 rather than by the large-signal piezoelectric coefficient d*33 of the (Bi,Na)TiO3-based ceramics. The significant decrease in the charge sensitivity in the vicinity of the depolarization temperature is closely related to the main intrinsic contribution to the piezoelectricity, i.e., the decrease in the crystal anisotropy associated with the temperature-induced polar ferroelectric-nonpolar relaxor phase transition.

Polarization orientation dependence of piezoelectric losses in soft lead Zirconate-Titanate ceramics

Dielectric, elastic and piezoelectric losses are investigated in soft Pb(Zr,Ti)O3-based piezoelectric ceramics in terms of polarization direction dependence of the properties. The difference of the mechanical quality factor at the resonance and anti-resonance frequencies were obtained by the impedance method. The polarization angle of the samples varied from 0 (E//PS) to 90 degree (E⊥PS) for “effective” k31 and k33 vibrating modes. The change in the piezoelectric losses is dominant in comparison to the dielectric or elastic losses in both vibration modes.

Composition Dependence of Crystal Structure, Electronic Structure, Ferroelectric and Piezoelectric Properties of (K,Na,Li)NbO3

INTRODUCTION Pb(Zr,Ti)O3-based piezoelectric ceramics have been widely used in electronic devices because of their excellent piezoelectric properties. Recently, owing to growing concern about environmental problems, the development of alternative piezoelectric ceramics is highly expected because Pb(Zr,Ti)O3 (PZT) contain a toxic element. (K,Na)NbO3(KNN) is one of the promising candidates.1) Superior characteristics of PZT is considered to be due to the morphotropic boundary (MPB), and KNN is also known to have a phase boundary similar to MPB. However, the characteristics and the crystal structure in the phase boundary are not well understood at the moment. It was also reported that substituting Li to the A-site of the perovskite structure ABO3 induces phase transition to tetragonal the KNN.2) From such backgrounds, we synthesized (K0.45Na0.55Lix)NbO3 and tried to reveal the composition dependence of the properties, the crystal and electronic structures in the phase boundary. In addition, we replaced the B-site by Ta, V and Mo partially, and then examined effects of the substitutions on the properties. EXPERIMENTAL Starting materials were wet-mixed in appropriate proportions, and then calcined in air for 2 h at 900 ℃. Thereafter, the samples were ground by a ball mill, and then sintered by the spark plasma sintering (SPS) method under a uniaxial pressing at 50 MPa for 5 min at 1050 ℃ in vacuum. For the obtained products, an recovery annealing treatment was performed at 900 ℃ for 4 h in O2. The identification of the phases and the evaluation of the lattice parameters were performed by XRD. Metal compositions of the ceramics were measured by ICP. Relative densities of the pellets were estimated by the Archimedes method. P-E hysteresis loop measurements were carried out at various frequencies using a TF-2000FE device (aixACCT) with the virtual ground mode. The surface and cross-section morphologies of the samples were observed by SEM. The temperature dependences of the dielectric permittivity (ε s ) and dielectric losses (tanδ) of the samples were measured by a LCR meter (HP-4284A). For average crystal structure analysis, we performed Rietveld analysis (RIETAN-FP) using synchrotron X-ray diffraction patterns.(BL19B2, spring-8) The electron densities were determined by the maximum entropy method (MEM) using the Dysnomia program. RESULTS AND DISCUSSION Figure 1 shows XRD patterns of (K0.45Na0.55Lix)NbO3 (x=0~0.07). These samples could be identified as the perovskite structures with the tetragonal (P4mm) and/or the orthorhombic (Amm2) symmetries. According to the crystal structure analysis by Rietveld method, in the composition of x=0.04~0.07, good fit can be obtained in a two-phase analysis of Amm2 and P4mm. These results indicate that there is a phase boundary around the composition range. It was found that all of the sample were sufficiently dense by the Archimedes method and the SEM observation. Measurements of P-Ehysteresis loop, the relative dielectric constant and dielectric loss demonstrated that the properties were improved in the x = 0.05~ 0.07. Such a change of the properties were examined from the electronic structure analysis by MEM and crystal structure analysis by Rietveld method. Further, we also investigated B-site substitution with a phase boundary, and evaluated their effect of the ferroelectric properties. REFERENCE 1)Y. Saito, et al. Nature, 432,84 (2004). 2) Hongliang Du, et al. Appl. Phys. Lett. 91, 182909 (2007). Figure 1

Large electrostrictive effect and strong photoluminescence in rare-earth modified lead-free (Bi0.5Na0.5)TiO3-based piezoelectric ceramics

In this study, new lead-free luminescent electrostrictive materials have been fabricated by introducing trivalent RE3+ (RE=Sm, Pr and Eu) as the activator into 0.93(Bi0·5Na0.5)TiO3–0.07BaTiO3 (BNBT7) ceramics. A high, purely electrostrictive effect with exceptionally good temperature-independent and fatigue-free behavior was obtained in RE-modified BNBT7 ceramics. These materials are also attractive for their strong photoluminescence with bright reddish-orange emission (RE=Sm) or red emission (RE=Pr, Eu) upon blue or green light excitation. These results suggest that this kind of materials has potential application as a multifunctional device by integrating its excellent luminescence and electrostrictive properties.

Phase structure–electrical property relationships in Pb(Ni1/3Nb2/3)O3–Pb(Zr,Ti)O3-based ceramics

Generally, the phase structure change of Pb(B′ B″)O3–PZT solid solutions near a morphotropic phase boundary (MPB) can be originated from composition variations. Here our results show that the excess PbO and the sintering temperature can also result in the ferroelectric phase structure change in the Pb(Ni1/3Nb2/3)O3–Pb(Zr,Ti)O3 (PNN–PZT)-based ceramics near the MPB. The dielectric, piezoelectric, and ferroelectric properties are dependent on the tetragonal phase content (TP) which is closely associated with the excess PbO and the sintering temperature. The temperature dependence of the polarization (P)–electric field (E) hysteresis loops reveals that the tetragonal phase in the PNN–PZT-based ceramics has a lower activation energy (Ea) for domain wall movement than that of the rhombohedral phase, thus resulting in easier polarization rotation. This is responsible for the phase structure–electrical property relationships in the PNN–PZT-based ceramics, exhibiting the dependence of the tetragonal phase content (TP) on the electrical properties.

High electrostrictive coefficient Q33 in lead-free Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 piezoelectric ceramics

In this study, the electrostrictive effect in Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 (BZT-xBCT, x = 0.4, 0.5, and 0.6) ceramics was investigated to gain understanding of their high piezoelectric activity. The electrostrictive coefficient Q33 of the BZT-xBCT ceramics was observed to be around 0.04 m4/C2, twice that reported for Pb(Zr,Ti)O3-based ceramics. The Q33 was found to be quite stable with respect to temperature and composition for the BZT-xBCT ceramics. The addition of Fe3+ dopant to the ceramics greatly decreased their Curie temperature without affecting their Q33, which remained 0.04 m4/C2. Moreover, a high and hysteresis-free electric-field-induced strain was obtained for 2 at. % Fe-doped BZT-0.5BCT ceramics at room temperature, caused by their high Q33 coefficient and lower-than-room-temperature Curie temperature. The small-signal M33 coefficient of 2 at. % Fe-doped BZT-0.5BCT ceramics was found to be 1.5 × 10−16 m2/V2 (0.32 × 10−16 m2/V2 for undoped counterpart). These results indicate that 2 at. % Fe-doped BZT-0.5BCT ceramics have great potential as alternatives for hard Pb(Zr,Ti)O3 ceramics in actuator applications, where reproducible and non-hysteretic deformation responses are required.

Effects of NiO addition on (K,Na,Li)NbO3–BaZrO3–(Bi,Na)TiO3-based ceramics

The effects of CuO or NiO addition on the sintering temperature and electrical properties of 0.92(K0.47Na0.47Li0.06)NbO3–0.07BaZrO3–0.01(Bi0.5Na0.5)TiO3 ceramics with a temperature-stable morphotropic phase boundary were investigated. The ceramics without any additives and those with NiO exhibited a tetragonal phase. The ceramics with CuO exhibited the coexisting orthorhombic and tetragonal phases. The sintering temperature was reduced by the addition of NiO or CuO. NiO addition was also effective for broadening the range of the sintering temperature window. The d33, radial-mode electromechanical coupling factor, and remanent polarization of the ceramics with NiO were 238 pC/N, 0.39, and 14 µC/cm2, respectively; moreover, the measured values of the ceramics with CuO were all lower than those of the ceramics with NiO. The results suggest that NiO acted as a sintering aid among grains, and the sintering temperature window was consequently broadened. In the case of CuO addition, Cu ions replaced the A- and B-sites of the ceramics, and such replacement reduced the tetragonality. As a result, the electrical properties of the ceramics with CuO were lower than those of the ceramics with NiO.

Composition Dependence of Average and Local Structures, Electron Density Distribution and Ferroelectric Properties in (Pb,RE)(Zr,Ti,Nb)O3 (RE=La,Nd)

INTRODUCTION Ferroelectric and piezoelectric properties are observed in some inorganic compounds, and the materials are expected to be applied for electronic devices like a memory. Among these material, Pb(Zr,Ti)O3-based ceramics are widely used in piezoelectric devices because of their excellent properties. It has been also reported that photovoltaic effect can be observed in the materials where Pb is substituted partially by La, i.e., (Pb,La)(Zr,Ti)O3 1). In addition, we reported that ferroelectric properties and crystal structures of (Pb,La)(Zr,Ti,Nb)O3 2) and discussed the simultaneous substitutions of La and Nb. These previous works demonstrated that both the La and Nb substitutions affected considerably the ferroelectric properties and the crystal and electronic structure of Pb(Zr,Ti)O3-based materials, but influences of the rare earth species (RE) and Zr/Ti ratio on these properties in (Pb,RE)(Zr,Ti,Nb)O3 are ambiguous at the moment. In order to clarify them, we synthesized Pb(Zr1-xTixNb0.03)(1-0.03/4)O3 (PZTN) and (Pb0.97RE0.03)(Zr1-xTixNb0.03)(1-0.03/4)O3(PREZTN) by the solid-state method in this work. By carrying out powder neutron diffraction measurement, we examined a relation between the dielectric, ferroelectric properties and replacement species, Zr/Ti ratio from the viewpoint of the crystal structure. EXPERIMENTAL PZTN and PREZTN powders with PbSiO3 (PSO) addition were synthesized by a solid-state method using PSO, PbO, La2O3, Nd2O3, ZrO2, TiO2 and Nb2O5. After wet mixing, mixtures of these starting materials were heated at 1000 oC for 6 h in air. The samples were then molded into pellets at uniaxial pressure of 40 MPa, and heated at 1150 oC for 2 h in lead atmosphere.Identification of the phases and evaluation of the lattice parameter were carried out by X-ray diffractions (XRD). Compositions of metal constituents were measured by the inductively coupled plasma (ICP) analysis. Relative densities of the ceramics were estimated by the Archimedes method. Surface and cross-section morphologies of the samples were observed by the scanning electron microscope (SEM). P-E hysteresis loop measurements were carried out at various frequencies using a TF-2000FE device (aixACCT) with the virtual ground mode. Temperature dependences of dielectric permittivities (e s ) and dielectric losses (tand) of the samples were measured by a LCR meter (HP-4284A). For average crystal structure analysis, we performed Rietveld analysis (RIETAN-FP) using synchrotron X-ray diffractions(BL02B2, SPring-8). Electron densities were determined by the maximum entropy method (MEM) using the Dysnomia program. For local crystal structure analysis, we performed both the Rietveld analysis (GSAS) and pair distribution function (PDF) analysis (PDFgetN, PDFFIT) using powder neutron total scattering data(HIPPO, LANSCE).RESULTS AND DISCUSSION PZTN and PREZTN could be identified as a single phase (P4mm) by the powder XRD. SEM and the Archimedes method revealed that densities of PREZTN were higher slightly than that of PZTN although all the samples had sufficient densities to measure ferroelectric properties. Figure 1 shows the P-E hysteresis loop of PZTN and PREZTN. The samples with the RE replacement showed higher remanent polarization (P r) and lower coercive field (E c) than PZTN. One of the reasons may be due to the higher density. In the dielectric measurement, it was found that the Curie temperature (T c) was reduced and a dielectric curve become broader by replacing RE for Pb. From the result of the Rietveld analysis using synchrotron X-ray diffractions of these samples, it was indicated that (Zr, Ti, Nb)-O6 octahedral distortion were relaxed by the RE substitution. This fact suggests that the relaxation of the crystal lattice distortion affects the decrease of T c. Figure 2 shows line profiles of electron density distributions analyzed by MEM. Considering that a change in electron density between (Zr, Ti, Nb) and O reflects a change in the bond strength, it suggests that the RE substitution has an influence on the bonding state of (Zr, Ti, Nb)-O. We also performed the local structure analysis using powder neutron total scatterings. REFERENCE1) Haertling GH, LAND CE, J.Am.Cer.Soc. , 54, 1(1971).2) N. Kitamura, T. Mizoguchi, T. Itoh, Y. Idemoto, J. Solid State Chem. , 210 , 275-279(2014)

The effects of sintering atmosphere on microstructures and electrical properties of lead-free (Bi0.5Na0.5)TiO3-based ceramics

0.93(Bi0.5Na0.5)TiO3–0.07BaTiO3 (BNT–7BT) piezoelectric ceramics sintered in O2 and N2 have been investigated to understand the effects of sintering atmosphere in defects, microstructures, and dielectric properties. The BNT–7BT ceramics sintered in O2 and N2 exhibit a major pseudo-cubic structure with slight distortion from the cubic cell. The specimen sintered in N2 atmosphere shows larger grain sizes than the specimen sintered in O2. The X-ray photoelectron spectroscopy (XPS), SEM–EDS, and TEM–EDS suggest that specimen sintered in N2 atmosphere exhibits more ion vacancies. Leakage current measurements suggest more oxygen vacancies for specimen sintered in N2. A higher remnant polarization and lower coercive field were observed for specimen sintered in O2. Strain vs. E field (S–E) loops display higher E-field induced strain up to 0.256% and higher dielectric permittivity for specimen sintered in O2. This work suggests that sintering in the O-rich atmosphere can reduce defects and enhances ferroelectric, dielectric, and piezoelectric properties.

Domain Contribution to Elastic Nonlinearity in Pb(Zr, Ti)O<sub>3</sub>-Based Piezoelectric Ceramics

In order to clarify the origin of the elastic nonlinearity in piezoelectric ceramics, the effect of Mn substitution into Pb (Zr,Ti)O3-based ceramics on the nonlinear elastic stiffness was investigated by analyzing the transient response after burst excitation. The real part of 3rd-order elastic stiffness drastically decreased with increasing Mn content. It was also found that the appearance of the elastic nonlinearity enhanced the mechanical loss. From the results, the irreversible domain wall motion overcoming the potential barrier due to defect complexes was considered as a possible origin of the elastic nonlinearity.

Investigation of High-Power Properties of (Bi,Na,Ba)TiO3 and (Sr,Ca)2NaNb5O15 Piezoelectric Ceramics

We investigated why the nonlinear behaviors of (Bi,Na,Ba)(Ti,Mn)O3 (BNBTM) ceramics and (Sr,Ca)2NaNb5O15 (SCNN) ceramics occur in comparison with Pb(Zr,Ti)O3-based (PZT) ceramics by evaluating their high-power properties with the distinction between mechanical nonlinearity and temperature dependence of properties. The equivalent stiffness of PZT decreased with increasing vibration velocity and sample temperature. However, the equivalent stiffnesses of BNBTM and SCNN did not depend on vibration velocity, they decreased and increased linearly with an increase in sample temperature, respectively. The nonlinear behavior of PZT originated from the soft-spring effect through which the mechanical nonlinearity was induced and the temperature dependence of stiffness was enhanced. On the other hand, it appeared that the nonlinear behaviors of BNBTM and SCNN originated from the apparent soft- and hard-spring effects through which the temperature dependence of stiffness was induced. The temperature characteristic of elasticity is important for controlling the high-power properties.

Low-temperature sintering of lead-free Bi1/2(Na,K)1/2TiO3-based electrostrictive ceramics with CuO addition

This study investigated low-temperature sintering of (Bi1/2Na1/2)TiO3-based electrostrictive ceramics by employing CuO as a sintering aid. Ceramic specimens with a composition of 0.96Bi1/2-(Na0.82K0.18)1/2TiO3-0.04BaZrO3 were prepared using a conventional solid-state reaction route. Without CuO, specimens required sintering temperatures (T s ) over 1175 °C for sufficient densification while the addition of 0.02-mol CuO in excess decreased the T s down to 1100 °C. A normalized strain, S max /E max , of 363 pm/V was obtained for a CuO-added specimen after sintering at 1100 °C, which was better than that of a high-temperature fired specimen sintered at 1175 °C without CuO (333 pm/V). The CuO-added specimen showed a high electrostrictive constant, Q 33, of 0.023 m4C−2, comparable to that of the Pb(Mg1/3Nb2/3)O3 (PMN) ceramic, which is believed to open a new road for the realization of low cost lead-free ceramic actuators.

Giant electric-field-induced strains in lead-free ceramics for actuator applications – status and perspective

In response to the current environmental regulations against the use of lead in daily electronic devices, a number of investigations have been performed worldwide in search for alternative piezoelectric ceramics that can replace the market-dominating lead-based ones, representatively Pb(Zr x Ti1-x )O3 (PZT)-based solid solutions. Selected systems of potential importance such as chemically modified and/or crystallographically textured (K, Na)NbO3 and (Bi1/2Na1/2)TiO3-based solid solutions have been developed. Nevertheless, only few achievements have so far been introduced to the marketplace. A recent discovery has greatly extended our tool box for material design by furnishing (Bi1/2Na1/2)TiO3-based ceramics with a reversible phase transition between an ergodic relaxor state and a ferroelectric with the application of electric field. This paired the piezoelectric effect with a strain-generating phase transition and extended opportunities for actuator applications in a completely new manner. In this contribution, we will present the status and perspectives of this new class of actuator ceramics, aiming at covering a wide spectrum of topics, i.e., from fundamentals to practice.

The temperature effect on the resonant spectra of thin piezoelectric ceramic disk

This study examines the influence of the temperature on the low-frequency resonant spectrum of piezoelectric ceramics based on lead zirconate titanate solid solution Pb(Zr,Ti)O3-based piezoelectric ceramics with heat variations ranging from 25 to 150°C, concluding that temperature increases cause the resonant spectrum to shift to higher frequencies. Furthermore, the variation in fundamental series resonant frequency fs (with temperature variation) is larger than the variation of fundamental parallel resonant frequency fp (with temperature variation). Another result of increased temperature is the decrease in effective electromechanical coupling factor keff. Finally, the effect of temperature on the overtone mode is more obvious than that of the fundamental mode.

Effect of substitution of titanium by magnesium and niobium on structure and piezoelectric properties in (Bi1/2Na1/2)TiO3 ceramics

To develop new (Bi1/2Na1/2)TiO3-based ceramics with excellent piezoelectric properties, the similarities and the differences between PZT and (Bi1/2Na1/2)TiO3 ceramics were analysed. Based on the analysis, a new (Bi1/2Na1/2)TiO3-based piezoelectric ceramic of B-site substitution of complex ions (Mg1/3Nb2/3)4+ for Ti4+ was prepared by a conventional ceramic technique, and the effect of complex ions (Mg1/3Nb2/3)4+ addition on the microstructure, dielectric and piezoelectric properties was investigated. The research results show that all compositions are mono-perovskite phase and the grain size increases with increasing content of (Mg1/3Nb2/3)4+. The piezoelectric constant d 33 first increases and then decreases, and electromechanical coupling factor k p varies insignificantly with increasing content of (Mg1/3Nb2/3)4+.