Effect of lead zirconate titanate on microstructure, mechanical and electrical properties of bismuth sodium lanthanum titanate ceramics (original) (raw)
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Scienceasia, 2020
The effects of sintering condition on phase evolution, physical, microstructure and dielectric properties of the PZT-3BLNT ceramics were investigated. The samples were prepared by a conventional mixed oxide method and sintered at the temperatures ranging from 1050-1200°C under normal atmosphere for 2 h dwell time with a heating/cooling rate of 5°C/min. X-ray diffraction indicated that the mixed rhombohedral-tetragonal phases were observed at lower sintering temperature of 1050°C, while the tetragonal phase became dominant at higher sintering temperature (1200°C). The optimum sintering temperature for preparation of high-density PZT-3BLNT ceramic was found to be 1200°C. Linear shrinkage and average grain size tended to increase with increasing the sintering temperature. The effects of annealing conditions on mechanical and dielectric properties of the PZT-3BLNT ceramic sintered at 1200°C were also studied in this work. It was found that the maximum room temperature dielectric constant (r) of 1313 and Vickers hardness (H V) of 4.38 GPa were achieved for the sample annealed at 950°C for 8 h dwell time and this value was ∼18-20% higher than that of the unannealed sample. This result was also well correlated with the maximum relative density observed for this annealing condition.
Journal of the European Ceramic Society, 2007
In the present investigation we studied the effect of lead content on a hard type ceramics starting from lack to excess PbO. Specimens of Pb x (Mn 0.017 Sb 0.033 Zr 0.48 Ti 0.47)O 3 with 0.96 ≤ x ≤ 1.06 were prepared by conventional oxide mixing technique and sintered at temperatures between 1280 and 1350 • C. In samples with lower Pb concentration the pyrochlore phase appeared, while in those with higher Pb an excess of PbO phase was detected. These phases proved detrimental for the properties of sintered ceramics. The highest values of piezoelectric properties were observed only for samples with an excess lead of about 2% sintered at 1340 • C, indicating that it represents the optimum amount of PbO. For such samples, the density ρ was 7.77 g/cm 3 , the remnant polarization P r was 37 C/cm 3 the planar coupling coefficient k p was 0.57 and the charge constant d 33 was 340 pC/N.
Physica B: Condensed Matter, 2013
The perovskite Pb (1 À x) Ba x Zr 0.55 Ti 0.45 O 3 material (x ¼0.00, 0.01, 0.02, 0.03, 0.05, and 0.07) was synthesized by solid state reaction route. Green bodies were sintered at 1250 1C. All samples were subjected to X-ray diffraction analysis and they were found to be in single phase. Dielectric properties were studied as a function of temperature and frequency. Ferroelectric properties were studied as a function of temperature. Remnant polarization, saturation polarization and coercive field were determined for all the samples using ferroelectric loops. Piezoelectric properties such as d 33 and electromechanical coupling factor (k p) were also measured at room temperature for all samples.
Low-Temperature Sintering of Barium Calcium Zirconium Titanate Lead-Free Piezoelectric Ceramics
Journal of the Korean Ceramic Society, 2013
The need for lead-free piezoceramics has caused a renewal of interest in BaTiO 3-based systems. Recently, it was found that ceramics in the (Ba,Ca)(Zr,Ti)O 3 system have properties comparable to those of Pb(Zr,Ti)O 3. However, these ceramics require rather high sintering temperatures of 1450-1550 ο C. In this work, the effect of TiO 2 and CuO addition on the sintering behavior, microstructure, dielectric and piezoelectric properties of (Ba 0.85 Ca 0.15)(Zr 0.1 Ti 0.9)O 3 (BCTZ) ceramics will be discussed. BCTZ ceramics were prepared by the mixed oxide route and 1 mol % of TiO 2 or CuO was added. Undoped and doped ceramics were sintered at 1350°C for 1-5 h. CuO was found to be a very effective sintering aid, with samples sintered for 1 h at 1350 ο C having a bulk density of 95% theoretical density; however the piezoelectric properties were greatly reduced, probably due to the small grain size.
Current Applied Physics, 2008
The near morphotropic phase boundary (MPB) of lead-free piezoelectric ceramics based on bismuth sodium lanthanum titanate (Bi 0.487 Na 0.487 La 0.017 TiO 3 :BNLT) and barium titanate (BaTiO 3 :BT) was carefully investigated by a modified two step mixed-oxide method. In this case the BNLT and BT powders were produced separately using calcination temperatures of 900°C and 1200°C, respectively. After that they were mixed with the desired compositions of (1 À x)BNLT-xBT, where x = 0.00, 0.02, 0.04, 0.06, 0.08, and 0.10. Then the powders were pressed and subsequently sintered at various temperatures to obtain the maximum density under each condition. It was found that the BT addition has a significant effect on grain growth inhibition of the BNLT-BT ceramics and this in turn gave rise to an enhancement in dielectric constant (e r ) of the corresponding ceramics. The piezoelectric coefficient (d 33 ) was also improved greatly to about 130 pC/N in the 0.96BNLT-0.04BT ceramic sample sintered at 1125°C. This offered an opportunity to obtain a good candidate for replacing the lead-based piezoelectrics.
Structural and ferroelectric properties of lanthanum modified BPZT ceramics
Materials Chemistry and Physics, 2011
Lanthanum modified Ba0.80Pb0.20Ti0.90Zr0.10O3 (BPZT) ceramics with composition Ba0.80−xLax Pb0.20Ti0.90Zr0.10O3; x = 0–0.01 in steps of 0.0025 were prepared by conventional solid state method. All the samples were sintered at 1325 °C after compacting in circular discs. Detailed structural and ferroelectric properties were carried out for sintered specimens. X-ray diffraction analysis for all the sintered specimens shows tetragonal structure with perovskite. Coercive field (Ec) and remanent polarization (Pr) to spontaneous polarization (Ps) ratio (Pr/Ps) was found to decrease with increase in temperature. Pr/Ps ratio was found to decrease with increase in x, except x = 0.0025.
Journal of Materials Science: Materials in Electronics, 2020
This article describes preparation of Barium (Zirconium) Titnate (BaZr 0.2 Ti 0.8 O 3) ceramics by the sol-gel technique and its structural, dielectric, ferroelectric, and piezoelectric properties investigated with sintering temperature variation. The phase and microstructure analysis of the sintered ceramics was carried out by X-ray diffraction method (XRD) and scanning electron microscopy (SEM), respectively. XRD analysis revealed structural transformation from cubic to tetragonal phase with increase in sintering temperature. Dielectric properties have been measured with variation of frequency up to 1 MHz and with temperature up to 200°C. The BZT ceramics exhibit diffuse phase transition with normal ferroelectric behavior. Hysteresis loop measurements disclosed that BZT ceramics have good ferroelectric nature with saturation at higher applied electric fields. Leakage current density show negative temperature coefficient resistance (NTCR) behavior. The highest value (261 pC/N) of piezoelectric coefficient (d 33) has been obtained for BZT ceramic sintered at 1400°C and revealed that ceramics have great potentials for electronic industry based on sensor technology.
Defence Science Journal, 2013
Lead zirconate titanate (PZT) based ceramics attracted the technologists and researchers for sensor and actuator applications because of the excellent piezoelectric properties 1,2. Mechanical quality factor (Q m), dielectric loss factor (tan δ), dielectric constant (T K 3), piezoelectric charge coefficient (d 33), piezoelectric voltage coefficient (g 33) are the important parameters which decide the suitability of the material for particular application. Materials with high Q m and low tan δ are suitable for ultrasonic and high frequency applications. Materials with higher T K 3 and d 33 are suitable for actuator applications like vibration and noise control, benders, optical positioning etc. 3,4. Materials with higher g 33 are useful for sensor applications 5. Particularly, materials with higher d 33 , g 33 and higher figure of merit (d 33 x g 33) are suitable for power harvesting applications since they offers higher power output 6-9. Incorporating the suitable dopant and optimising the process parameters, desired properties can be obtained. Sintering parameters viz. atmosphere, temperature, time and heating rate have significant effect on microstructure and thus on electromechanical properties of the final product 10,11. Dense microstructure with optimum grain size formed during sintering results in better dielectric and piezoelectric properties 12. In our earlier studies,effect of Zr/Ti ratio 13 and lanthanum concentration 14 on power harvesting properties of ferroelectric composition Pb(Ni 1/3 Sb 2/3)-(ZrTi)O 3 were investigated. In the present study, ferroelectric composition Pb 0.98 La 0.02 (NiSb) 0.05 [(Z r 0.52 Ti 0.48) 0.995 ] 0.95 O 3 14 was investigated for the effect of sintering time on the microstructure and electromechanical properties viz. Qm, kp, T K 3 d 33 , g 33 and figure of merit. Study was also aimed towards analysing the suitability of this composition for power harvesting applications and its comparison with PZT type 5A. 2. EXPERIMENTAL Lanthanum doped Pb(Ni 1/3 Sb 2/3)-(ZrTi)O 3 ferroelectric composition Pb 0.98 La 0.02 (NiSb) 0.05 [(Zr 0.52 Ti 0.48) 0.995 ] 0.95 O 3 [La-PNS-PZT] was synthesised by mixed oxide route using the oxides of elements.Raw material powders NiO (97%, Acros), Sb 2 O 5 (99%, Loba Chemie), PbO (99.5%,Waldies Ltd., Kolkata), ZrO 2 (99.37%, Loba Chemie) and TiO 2 (98.5%, Travancore Titanium Products) were wet milled in pure water medium for 24 hours. Calcination was performed at 1060 °C followed by wet milling. Phase formation of the calcined powder was analysed from slow scanned X-ray diffraction pattern recorded from 42° to 58° by X-Ray diffractometer (Make-PANalytical, Model-X'pert pro). Powder was granuled using polyvinyl alcohol as a binder. Discs of diameter 29 mm and 1.7 mm thickness were compacted using double ended die punch machine (Make-GMT) by maintaining green density near to 4.8 g/cc. Samples were sintered in lead rich environment at 1270 °C for 20 min, 40 min, 60 min, 80 min and 100 min. They were lapped to 1.2 mm thickness and electroded with silver paste, followed by poling. Microstructure of polished and chemically etched samples was studied using optical microscope. Capacitance (C at 1 kHz), resonance frequency (f r), anti
Journal of Electroceramics, 2006
The important properties of lead-free piezoelectric ceramics have been investigated from Bismuth Sodium Lanthanum Titanate and Barium Titanate system: (1 − y)(Bi 0.5 Na 0.5 ) (1−1.5x) La x TiO 3 (BNLT)-yBaTiO 3 (BT) where x = 0.017 and y = 0 − 0.2, respectively. The morphotropic phase boundary (MPB) was found to be around y = 0.1 by the x-ray diffraction and dielectric measurement at various amount of BT. The temperature dependence of dielectric constant (ε r ) at various value of y showed the diffuse phase transition exhibiting the relaxor type ferroelectrics. The degree of diffuseness increased at a high doping content of about y = 0.15 where the second phase transition (T 2 ) of the ferroelectric to antiferroelectric phase disappeared. Moreover, this sample had the maximum piezoelectric coefficient (d 33 ) of about 112 pC/N with relatively low dielectric constant. The optimum sintering temperatures and the microstructures of the dense BNLT-BT ceramics were also examined.
Journal of Applied Physics, 2009
The influence of the microstructural characteristics on the dielectric and electrical properties has been investigated for Nd3+ doped lanthanum modified lead zirconate titanate ferroelectric ceramics, obtained by the conventional solid-state reaction method, by taking into account different sintering conditions. The grain growth mechanism has been investigated and a cubic-type grain growth law was observed for samples with grain size varying from 1.00 up to 2.35 μm. The porosity and grain size dependences of the phase transition parameters, such as the maximum dielectric permittivity and its corresponding temperature (εm and Tm, respectively) were also investigated. The ac conductivity analyses followed the universal Jonscher law. The behavior of the frequency exponent (s) was analyzed through the correlated barrier hopping model. Both ac and dc conductivity results have been correlated with the observed microstructural features.