Electrocaloric properties of Sr and Sn doped BCZT lead-free ceramics

2020 ◽  
Vol 91 (2) ◽  
pp. 20905
Author(s):  
Satyanarayan Patel ◽  
Manish Kumar
Keyword(s):  
Electric Fields ◽  
Perovskite Phase ◽  
Entropy Change ◽  
Lead Free ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
Sn Doping ◽  
Adiabatic Temperature Change ◽  
Lead Free Ceramics ◽  
Pure Perovskite Phase

In the present work, the electrocaloric (EC) effect in lead-free Sr and Sn doped (Ba0.85Ca0.075Sr0.075)(Zr0.1Ti0.88Sn0.02)O3 ceramic prepared by solid-state method has been investigated. The phase purity and pure perovskite phase formation with Sr and Sn doping is confirmed by X-ray diffraction. The adiabatic temperature change ΔT (due to the EC effect), entropy change (ΔS) and refrigeration capacity (RC) are estimated under various electric fields. The maximum peak values of ΔT, ΔS and RC are found as 1.5 K, 1.8 J/kg.K and 2.75 J/kg, respectively under the applied electric field of 33 kV/cm at 305 K. It is also observed that the ΔT, ΔS and RC decreases with an increase in applied temperature. Moreover, the estimated values of EC properties are significantly high which indicates that fabrication of Sr and Sn doped lead-free ceramics can be advantageous for EC applications.

MICROSTRUCTURES AND PIEZOELECTRIC PROPERTIES OF KNNLST DOPING BCZT LEAD-FREE CERAMICS

2012 ◽  
Vol 05 (04) ◽  
pp. 1250041 ◽  
Author(s):  
WEI XU ◽  
YANG LI ◽  
JIAN-MIN FENG ◽  
YE-JING DAI
Keyword(s):  
Piezoelectric Properties ◽  
Perovskite Phase ◽  
Lead Free ◽  
X Ray Diffraction ◽  
X Ray ◽  
Practical Applications ◽  
Lead Free Ceramics ◽  
Pure Perovskite Phase ◽  
Average Grain Size ◽  
Piezoelectric Behavior

In this study, lead-free piezoelectric ceramics ( Na0.52K0.44Li0.04 )( Nb0.88Sb0.08Ta0.04 ) O3 -doped 0.52 Ba ( Zr 0.2 Ti 0.8) O 3-0.48( Ba 0.7 Ca 0.3) TiO 3( BCZT -x KNNLST ) are investigated. The effects of the KNNLST addition on the microstructures and the electrical properties of the ceramics sintered at the temperature as low as 1350°C are studied. The X-ray diffraction data show that the addition of KNNLST could diffuse into BCZT lattice and a pure perovskite phase is formed. With the increase of KNNLST addition, the average grain size is first increased and afterwards decreased. The ceramics with x = 0.005 exhibit a good piezoelectric behavior of d 33 ~ 464 pC/N and k p ~ 0.44 after three month's aging, which indicates the BCZT -x KNNLST ceramics could be promising for lead-free practical applications.

scholarly journals Structural, Dielectric and Ferroelectric Properties of Cu2+ and Cu2+/Bi3+ doped BCZT Lead-free Ceramics: A Comparative Study

2021 ◽  
Author(s):  
Sapna Kumari ◽  
Amit Kumar ◽  
V. Kumar ◽  
S. K. Dubey ◽  
P. K. Goyal ◽  
...  
Keyword(s):  
Perovskite Phase ◽  
Ferroelectric Properties ◽  
Solid State Reaction Method ◽  
Lead Free ◽  
X Ray Diffraction ◽  
Physical Mechanisms ◽  
A Value ◽  
Lead Free Ceramics ◽  
Pure Perovskite Phase ◽  
Perovskite Type

Abstract Perovskite type Ba0.98Ca0.02Zr0.02Ti0.98O3 (BCZT), Ba0.98Ca0.02Zr0.02Ti0.976Cu0.008O3 (BCZTC) and Ba0.9725Bi0.005Ca0.02Zr0.02Ti0.976Cu0.008O3 (BCZTCB) lead-free ceramics were synthesised via solid-state reaction method at a sintering temperature of ~ 1380°C. Effects of CuO and Bi2O3/CuO doping on structural, microstructural, dielectric, and ferroelectric properties were investigated systematically. X-ray diffraction technique confirmed the existence of pure perovskite phase with the tetragonal structure in pure and in the doped BCZT ceramics at room temperature. The dielectric analysis demonstrated two anomalies around 24°C and 126°C for BCZT, which were identified as orthorhombic to tetragonal (TO-T) and tetragonal to cubic (TC) phase transition temperature, respectively. The TO-T temperature shifted to below 16°C, while the TC increased to 132°C for the BCZTCB sample. The physical mechanisms of the conduction processes were investigated through impedance spectroscopy and the values of resistance, conductivity, and activation energies associated with the grain and grain boundaries were evaluated. The activation energy was determined to be higher for doped samples than for pure BCZT. Further, the dopant-dependent ferroelectric nature of the ceramic samples was evidenced by the analysis of characteristic hysteresis loop, and a value of remnant polarisation (Pr = 4.59 µC/cm2) was obtained for the BCZTCB ceramic sample. Furthermore, the d33 value, which was 54 pC/N for pure BCZT, was determined to be 140 pC/N and 64 pC/N for BCZTC and BCZTCB, respectively.

Effects of Dwell Time Sintering on Microstructure, Piezoelectric and Mechanical Properties of Modified BNT-Based Ceramics

2016 ◽  
Vol 675-676 ◽  
pp. 544-547
Author(s):  
Supalak Manotham ◽  
Thanatep Phatungthane ◽  
Tawee Tunkasiri ◽  
Komsanti Chokethawat
Keyword(s):  
Mechanical Properties ◽  
Dwell Time ◽  
Perovskite Phase ◽  
Microstructural Analysis ◽  
Lead Free ◽  
Ceramic Samples ◽  
Lead Free Ceramics ◽  
Pure Perovskite Phase ◽  
Sintering Method ◽  
Rhombohedral Symmetry

The properties of modified Bi0.5Na0.5TiO3 (BNT) based lead-free ceramics were investigated. The BNT-based ceramics were prepared by a two-steps sintering method. The ceramics were sintered at T1=1373 K and T2= 1173 K for various dwell times (0, 2, 4, and 8h). The properties of the ceramics were characterized by many techniques. The ceramic samples exhibited a pure perovskite phase with rhombohedral symmetry. The microstructural analysis by a scanning electron microscopy (SEM), indicated that all ceramics had a similar microstructure. Piezoelectric and mechanical properties of the ceramics were improved at a suitable dwell time at T2.

Piezoelectric and Strain Properties of Strontium-Doped BZT-BCT Lead-Free Ceramics

2012 ◽  
Vol 512-515 ◽  
pp. 1385-1389 ◽  
Author(s):  
Wang Feng Bai ◽  
Wei Li ◽  
Bo Shen ◽  
Ji Wei Zhai
Keyword(s):  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Piezoelectric Coefficient ◽  
Perovskite Phase ◽  
Ferroelectric Properties ◽  
Lead Free ◽  
Electromechanical Coupling Coefficient ◽  
Lead Free Ceramics ◽  
Pure Perovskite Phase ◽  
Free Material

Lead-free piezoelectric ceramics, (Ba0.85-xSrxCa0.15)(Zr0.1Ti0.9)O3 (BSCZT, x=0.01-0.07), were prepared via a solid-state reaction route. The dielectric properties, ferroelectric properties, piezoelectric and strain properties of BSCZT ceramics were studied. The phase structure and microstructure were investigated by X-ray diffraction and scanning electron microscope, respectively. Results showed that dense ceramics with pure perovskite phase were obtained. At room temperature, the samples with x=0.03 exhibited excellent properties with large piezoelectric coefficient d33=534pC/N, planar mode electromechanical coupling coefficient kp=47.7%, thickness mode electromechanical coupling coefficient kt= 42% and high strain levels of 0.34%. In addition, the study of electrical properties suggested that the Curie temperature decreased linearly from 92oc to 73oc with the increasing doping content of strontium in BCZT ceramics. The remnant polarizations, piezoelectric coefficient and strain levels were all increased as the Sr content increased and then decreased with further increased Sr doping level, giving the maximum values at the Sr content of 3mol%. These results indicated that the BSCZT system is a promising lead-free material for applications in the future.

scholarly journals Microstructural and Electrical Properties of Sn-Modified BaTiO3 Lead-Free Ceramics by Two-Step Sintering Method

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Wichita Kayaphan ◽  
Pornsuda Bomlai
Keyword(s):  
Electrical Properties ◽  
Curie Temperature ◽  
Dwell Time ◽  
Sintering Temperature ◽  
Perovskite Phase ◽  
Lead Free ◽  
Tetragonal Symmetry ◽  
Lead Free Ceramics ◽  
Pure Perovskite Phase ◽  
Structural And Electrical Properties

Ba(Ti0.92Sn0.08)O3 lead-free ceramics were prepared using a two-step sintering (TSS) technique. Varying the first sintering temperature T1 (1400 and 1500°C) and the dwell time t1 (0, 15, and 30 min), we obtained dense ceramics which were then soaked at a constant temperature of 1000°C (T2) for 6 h (t2). The structural and electrical properties were investigated. XRD results indicated that all the ceramics showed a pure perovskite phase with tetragonal symmetry. Density and grain size increased with higher T1 temperatures and increased t1 dwell times. Enhanced electrical properties were achieved by sintering at the optimized T1 sintering temperature and t1 dwelling time. At the lower T1 sintering temperature of 1400°C, the dielectric and piezoelectric properties and the Curie temperature of the ceramics were improved significantly by increasing t1 dwell time. Further, increasing the sintering temperature T1 to 1500°C, excellent properties were obtained at t1 = 15 min which then deteriorated when t1 was increased to 30 min. The electrical properties of the sample sintered under the T1/t1/T2/t2 condition of “1500/15/1000/6” showed the best values. For this sample the piezoelectric coefficient (d33), dielectric permittivity (εr), loss factor (tanδ), and Curie temperature (TC) were 490 pC/N, 4385, 0.0272, and 48°C, respectively.

Effect of Sintering Temperature on Electrical Properties of SFN Ceramics Doped with Al Prepared by a Solid-State Reaction Technique

2016 ◽  
Vol 675-676 ◽  
pp. 527-530
Author(s):  
Thanatep Phatungthane ◽  
Kachaporn Sanjoom ◽  
Denis Russell Sweatman ◽  
Buagun Samran ◽  
Chamnan Randorn ◽  
...  
Keyword(s):  
Solid State ◽  
Electrical Properties ◽  
Solid State Reaction ◽  
Sintering Temperature ◽  
Perovskite Phase ◽  
Dielectric Behavior ◽  
Orthorhombic Symmetry ◽  
X Ray Diffraction ◽  
Solid State Reaction Technique ◽  
Pure Perovskite Phase

In the present work, strontium iron niobate SrFe0.5Nb0.5O3 ceramics doped with aluminum were synthesized by a solid-state reaction technique. Phase formation investigation by X-ray diffraction technique (XRD) revealed that all ceramics exhibited pure perovskite phase with orthorhombic symmetry. Grain size observed by electron microscopy (SEM) was found to increase with increasing sintering temperature. The electrical properties and related parameters of the ceramics were also measured. The ceramics exhibit very good dielectric behavior and have a significant potential for dielectric applications.

The Electrical Properties of BCZT Lead-Free Ceramics Induced by BaZrO3 Seeds

2016 ◽  
Vol 690 ◽  
pp. 114-119
Author(s):  
Piewpan Parjansri ◽  
Manlika Kamnoy ◽  
Uraiwan Intatha ◽  
Sukum Eitssayeam ◽  
Tawee Tunkasiri
Keyword(s):  
Grain Size ◽  
Electrical Properties ◽  
Perovskite Phase ◽  
Nano Particle ◽  
Sintered Ceramic ◽  
Voltage Coefficient ◽  
Lead Free Ceramics ◽  
Seed Content ◽  
Pure Perovskite Phase ◽  
Average Grain Size

Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) ceramics were produced by using the seed-induced method. The nano-particle BZ (BaZrO3) seeds were mixed with BaCO3, CaCO3, ZrO2 and TiO2 powder for preparing by the mixed oxide method. The XRD results indicated that all powder and sintered ceramic samples showed a pure perovskite phase with coexistence between rhombohedral and tetragonal phase. As the BZ seed content increased, the density of ceramics tended to decrease from 5.61 g/cm3 to 5.37 g/cm3. The average grain size of the ceramics was in the range of 12.15 -13.50 mm. The dielectric loss (tand) was less than 0.03 for all samples at room temperature (at 1 kHz). Other electrical properties, including dielectric constant (εr), remnant polarization (Pr), and piezoelectric charge coefficient (d33) values decreased with increasing BZ seed doping with relates to the decreasing grain size and density of BCZT ceramics. However, the values of coercive field (Ec) decreased and piezoelectric voltage coefficient (g33) increased with BZ seed doping.

Effects of NaNbO3 Crystals on Electrical Properties of K0.5Na0.5NbO3 Ceramics

2016 ◽  
Vol 690 ◽  
pp. 126-130 ◽  
Author(s):  
Chavalit Suksri ◽  
Piewpan Parjansri ◽  
Sutatip Thonglem ◽  
Uraiwan Intatha ◽  
Sukum Eitssayeam ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Piezoelectric Properties ◽  
Perovskite Phase ◽  
Seed Crystal ◽  
Molten Salt Synthesis ◽  
X Ray Diffraction ◽  
Mixed Powder ◽  
X Ray ◽  
Structure And Morphology ◽  
Pure Perovskite Phase

Lead-free (K0.5Na0.5)NbO3 (KNN) piezoelectric ceramics were studied and synthesized by the seed-induced method. NaNbO3 crystal was used as seed and prepared by molten salt synthesis (MSS). The average particles size of NaNbO3 seed crystal was about 1-3 mm. Then, the NaNbO3 seed was mixed with KNN powder and ball milled for 24 h. The mixed powder was calcined at 700-900 °C and sintered at 1100 °C. The phase structure and morphology of the ceramics were investigated by X-ray diffraction and scanning electron microscope and the electrical properties were studied. The results indicated that all samples showed a pure perovskite phase. The highest density of the ceramic was 93% compared to the theoretical density. The results showed that NaNbO3seed crystal improved piezoelectric properties of KNN ceramics.

Low-temperature fabrication of pyroelectric Ba0.8Sr0.2TiO3 thin films by a sol-gel process

2001 ◽  
Vol 16 (3) ◽  
pp. 778-783 ◽  
Author(s):  
Jian-Gong Cheng ◽  
Jun Tang ◽  
Shao-Ling Guo ◽  
Jun-Hao Chu
Keyword(s):  
Perovskite Phase ◽  
Sol Gel ◽  
Pyroelectric Coefficient ◽  
X Ray Diffraction ◽  
Electrical Measurements ◽  
Pure Perovskite Phase ◽  
Average Grain Size ◽  
Sol Gel Process ◽  
Columnar Grains ◽  
Uncooled Infrared Detectors

Ba0.8Sr0.2TiO3 films were fabricated with a 0.05 M solution by a sol-gel process at temperatures between 550 and 650 °C. Analysis by x-ray diffraction, Raman spectroscopy, and scanning electron microscopy revealed that the films annealed at 650 °C showed pure perovskite phase, tetragonal structure, and columnar grains with an average grain size of 150 nm. Electrical measurements performed on the films annealed at 650 °C showed two dielectric peaks in the dielectric constant–temperature curve, a remnant polarization of 1.4 μC/cm2, a coercive field of 18.3 kV/cm, and good insulating property. The measured pyroelectric coefficient for the films annealed at 650 °C was larger than 3.1 × 10−4 C/m2K at the temperatures ranging from 10 to 26 °C and reached the maximum value of 4.1 × 10−4 C/m2K at 16 °C. The excellent pyroelectric property rendered the Ba0.8Sr0.2TiO3 films annealed at 650 °C promising for uncooled infrared detectors and thermal imaging applications.

Sign in / Sign up

Export Citation Format

Share Document