Enhanced Electrical Properties of 3-0 Type Na0.5Bi2.5Nb2O9-BaTiO3 Composite High-Temperature Piezoelectric Ceramics (original) (raw)
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Ceramics International, 2014
High insulating (1 À x)Na 0.5 Bi 0.5 TiO 3-xBaTiO 3 (x ¼0-0.08) ceramics were rapidly sintered at low temperature and then enhanced polarizations were observed. (1 Àx)Na 0.5 Bi 0.5 TiO 3-xBaTiO 3 nano-powders were prepared by the sol-gel method and then their ceramics were rapidly sintered at 920-1150 1C. According to the saturated ferroelectric hysteresis loops, the acquired saturated and remnant polarizations are 48μC/cm2and48 μC/cm 2 and 48μC/cm2and40 μC/cm 2 at x ¼0.03-0.08, and the coercive electric field decreases from 70kV/cmofpureNa0.5Bi0.5TiO3to70 kV/cm of pure Na 0.5 Bi 0.5 TiO 3 to 70kV/cmofpureNa0.5Bi0.5TiO3to30 kV/cm at x ¼0.06-0.08. Furthermore, the piezoelectric d 33 is 166.8 pC/N at x ¼0.06, where the morphotropic phase boundaries occur. These improved properties are achieved because the leakage current is reduced through compressing the loss of Na and Bi components during ceramics' preparation process.
Journal of Sol-Gel Science and Technology, 2019
In this work, lead-free 0.965Bi 0.5 Na 0.5 TiO 3-0.035BaTiO 3 (BNT-BT) piezoelectric ceramics were synthesized by a sol-gel process. X-ray diffraction pattern of the BNT-BT samples revealed that powder calcined at 600°C, exhibit a pure perovskite structure. Scanning electron microscopy (SEM) was used to find the surface morphology and grain size of the investigated ceramics. At an optimized sintering temperature of 1150°C, well-saturated ferroelectric (P-E) hysteresis loops with high remnant polarization (P r = 34.8 µC/cm 2) and low corrosive field (E c = 23 kV/cm) were obtained. Electric field-induced strain of 0.137% with a dynamic piezoelectric coefficient (d 33 * = 196 pm/V) was observed under 75 kV/cm drawing field. In addition, high static piezoelectric constant (d 33 = 138 pC/N) was recorded for the sample sintered at 1150°C. This value of d 33 is comparable to that of BNT-based bulk piezoelectric ceramics.
Japanese Journal of Applied Physics
The grain size effect on the dielectric, ferroelectric, and piezoelectric properties of BaTiO 3 (BT) ceramics with different Ba/Ti ratios, prepared by solid-state reaction and conventional sintering, was investigated, and the corresponding electrical properties of these ceramics with similar grain size were compared. The BT ceramics with Ba/Ti ratios of 0.997, 1.000, and 1.003 and grain sizes of approximately 1 μm exhibited dielectric constants of 4265, 4275, and 4835 and converse piezoelectric coefficients, d 33 *, of 703, 645, and 466 pm V −1 , respectively. The remanent polarization, P r , was relatively higher for Ba-excess BT ceramics. These results indicated that, in Ti-excess BT ceramics, domain walls were strongly pinned due to oxygen vacancies under small electric fields and they were de-pinned at high electric fields, contributing to the higher d 33 *, while the orientation of domains in high electric fields did not retain upon electric field unloading, resulting in lower P r .
Royal Society Open Science, 2021
The influence of different processing parameters and various Ba 2+ addition (up to 10 mol%) on the structure and dielectric properties of Bi 0.5 Na 0.5 TiO 3 -BaTiO 3 (BNT-BT) ceramics was investigated. The powders were hydrothermally synthesized in the alkaline environment at 180°C for different time periods. X-ray diffraction confirmed the presence of dominant rhombohedral Bi 0.5 Na 0.5 TiO 3 phase and a small amount of secondary pyrochlore Bi 2 Ti 2 O 7 phase in the pure BNT powders. In addition, one-dimensional Na 2 Ti 2 O 7 structure was also observed in the powder hydrothermally treated for a long time (i.e. 48 h). The amount of secondary pyrochlore phase in the BNT-BT powders increases with the increase of Ba 2+ content. The synthesized powders were pressed into pellets and finally sintered at various temperatures up to 1150°C. High density (more than 90%TD) was obtained in all BNT-BT sintered samples. Optimal sintering parameters were chosen in order to obtain dense ceramics...
Journal of Electroceramics, 2013
In this paper, lead-free (1-x)(Bi 0.5 Na 0.5 ) 0.94 Ba 0.06-TiO 3 -xBiAlO 3 (BNBT-BA, x00, 0.010, 0.015, 0.020, 0.025, and 0.030) piezoelectric ceramics were synthesized using a conventional solid-state reaction method. The effect of BiAlO 3 concentration on dielectric, ferroelectric and piezoelectric properties were investigated. The ferroelectric and piezoelectric properties of BNBT ceramics are significantly influenced by the presence of BA. In the composition range studied, X-ray diffraction revealed a perovskite phase with the coexistence of rhombohedral and tetragonal phases. The temperature dependence of dielectric properties showed that the depolarization temperature (T d ) shifted towards lower temperatures and that the degree of diffuseness of the phase transition around T d and T m became more obvious with increasing BiAlO 3 content. The remanent polarization increased with increasing BA, and reached a maximum value of 30 μC/cm 2 at x00.020. As a result, at x00.020, the piezoelectric constant (d 33 ) and the electromechanical coupling factor (k p ) of the ceramics attained maximum values of 188 pC/N and 34.4 %, respectively. These results indicate that BNBT-BA ceramics is a promising candidate for leadfree piezoelectric materials.
Materials Science-poland, 2011
The 0.935(Bi0.5Na0.5) TiO3 -0.065BaTiO3 (abbreviated as BNT6.5BT) lead-free ceramics were prepared by conventional solid state sintering technique. The effects of sintering temperature (1150–1200 °C) and poling condition on its piezoelectric properties were examined. Piezoelectric properties like the piezoelectric constant (d33) and electromechanical factors (kp , kt ) depend on the poling field and poling temperature, whereas different poling times, in the 5–30 min range, were not observed to have any significant effect on the piezoelectric properties. With respect to piezoelectric properties, the chosen sintering temperature range is suitable for BNT6.5BT ceramics.
Advances in Electroceramic Materials II
In this study, we report the synthesis, microstructural and electrical characterization of lead-free (1-x) Nai, 2Bi], 2Ti03-xBaTi03 (NBT-BT) ceramics with x= 0.05, 0.06, 0.07, 0.08, 0.09. NBT-BT ceramics were synthesized using conventional solid state reaction method. The piezoelectric response was optimized by synthesizing the compositions around morphotropic phase boundary (MPB). All the samples were characterized by XRD for structural information, scanning electron microscopy for ...