EFFECT OF YTTRIUM ON DIELECTRIC, PYROELECTRIC AND PIEZOELECTRIC PROPERTIES OF PBN FERROELECTRICS

2006 ◽  
Vol 20 (21) ◽  
pp. 3081-3091 ◽  
Author(s):  
K. SAMBASIVA RAO ◽  
N. VALLIS NATH ◽  
P. MURALI KRISHNA ◽  
D. MADHAVA PRASAD ◽  
JOON HYUNG LEE
Keyword(s):  
Transition Temperature ◽  
Spontaneous Polarization ◽  
Room Temperature ◽  
Piezoelectric Properties ◽  
Pyroelectric Coefficient ◽  
Tetragonal Symmetry ◽  
Maximum Volume ◽  
Stiffness Constant ◽  
Method Substitution ◽  
Sintering Method

Materials with batch formula Pb (1-x-3y/2) R y Ba x Nb 2 O 6, where R=Y, (1-x)=0.73, 0.63, 0.53 and y=0.00, 0.02 have been prepared by the double sintering method. Substitution of yttrium (Y) restored tetragonal symmetry of PBN but reduced lattice parameters, cell volume and enhanced the density. Transition temperature of PBN has decreased due to the substitution of Y3+. Enhanced room temperature spontaneous polarization (Ps)=149.97 μ C/sq. cm has been observed in PBN53, which is above MPB, whereas enhanced value of Ps=112.74 μ C/sq. cm is found in Y: PBN63 at MPB region. The room temperature Pyroelectric coefficient (PRT=1.07) has been observed in the composition where maximum volume of Ps is obtained. Similarly, enhanced values of piezoelectric coefficients Kp=0.244, Kt=0.353, K31=0.131, d31=60, d33=159 and g31=3.65 have also been found in the same material PBN53. Substitution of Yttrium enhanced the stiffness constant 13.59 in PBN 73 to 14.27 of Y: PBN73.

Structure and Piezoelectric Properties of (1-X)K0.49Na0.51NbO3-XLiTaO3 Lead-Free Piezoceramics

2010 ◽  
Vol 663-665 ◽  
pp. 1310-1313 ◽  
Author(s):  
Yue Ming Li ◽  
Liang Jiang ◽  
Zhong Yang Shen ◽  
Run Hua Liao ◽  
Zhu Mei Wang
Keyword(s):  
Phase Transition ◽  
Room Temperature ◽  
Electromechanical Coupling ◽  
Piezoelectric Properties ◽  
Lead Free ◽  
Electromechanical Coupling Coefficient ◽  
Orthorhombic Symmetry ◽  
Coexistence Region ◽  
Solid State Sintering ◽  
Sintering Method

Lead-free (1-x)K0.49Na0.51NbO3-xLiTaO3 (x=0.00-0.07) piezoceramics were fabricated by the conventional solid-state sintering method, the effects of LiTaO3 content on the phase structure and piezoelectric properties of the ceramics were investigated. All the ceramics show single perovskite structure with a phase transition from an orthorhombic symmetry to a tetragonal one across an orthorhombic-tetragonal coexistence region with 0.04<x<0.06. For the ceramic sample with x=0.05, due to the coexistence of orthorhombic and tetragonal phases near room temperature, enhanced piezoelectric constant d33=236 pC/N and planar electromechanical coupling coefficient kp=40.9% are observed. In addition to other good electrical properties such as εr=969, tgδ=0.015 and Qm=41, this ceramic is a promising lead-free piezoelectric material.

scholarly journals PLZT Microfibers Technology Optimization

2016 ◽  
Vol 61 (3) ◽  
pp. 1471-1476
Author(s):  
L. Kozielski ◽  
M. Adamczyk ◽  
K. Feliksik ◽  
D. Bochenek ◽  
F. Clemens
Keyword(s):  
Spontaneous Polarization ◽  
Laser Excitation ◽  
Piezoelectric Properties ◽  
Sintering Temperature ◽  
Waste Heat ◽  
Pyroelectric Coefficient ◽  
Ferroelectric Materials ◽  
Quick Response ◽  
New Generation ◽  
Ferroelectric And Piezoelectric Properties

Abstract Electrocaloric (EC) structures for a new generation of cooling or heating elements utilize the temperature dependence of spontaneous polarization in some ferroelectric materials to convert waste heat into electricity and vice versa. A (Pb0.93La0.07) (Zr0.65Ti0.35)O3 material, have the largest recorded pyroelectric coefficient. An effective predicted form for such applications is fiber, due to small heat capacitance and quick response time, even for nano second laser excitation. Consequently, the presented work provides a description of the optimization of structural, ferroelectric and piezoelectric properties of obtained fibers, finally concluding on necessity of sintering temperature reduction in 100°C in contrast to bulk form to effectively prevent its destruction.

scholarly journals Large electro-strain signal of the BNT–BT–KNN lead-free piezoelectric ceramics with CuO doping

2019 ◽  
Vol 09 (03) ◽  
pp. 1950022 ◽  
Author(s):  
Zhi-Hao Zhao ◽  
Rui-Fang Ge ◽  
Yejing Dai
Keyword(s):  
Transition Temperature ◽  
Solid State ◽  
Room Temperature ◽  
Ferroelectric Phase ◽  
Piezoelectric Properties ◽  
The Other ◽  
Lead Free ◽  
State Process ◽  
Relaxor State ◽  
Strain Signal

This paper investigates a system of 0.93[Formula: see text][Formula: see text]TiO3–0.06BaTiO3–0.01[Formula: see text][Formula: see text]NbO3–[Formula: see text]CuO (BNT–BT–KNN–[Formula: see text]CuO, [Formula: see text][Formula: see text]mol.%) ceramics, which were fabricated by the conventional solid-state process through the granulation of vacuum freeze drier. The results show that the CuO doping made a significant enhancement on the piezoelectric properties of the BNT–BT–KNN ceramics. With the doping of CuO, the transition temperature between ferroelectric phase and ergodic relaxor state is reduced to near room temperature, resulting in pinched [Formula: see text]–[Formula: see text] loops and “sprout” shape [Formula: see text]–[Formula: see text] curves. For the composition with [Formula: see text], a high unipolar strain of 0.39% under 5[Formula: see text]kV/mm contributes a large [Formula: see text][Formula: see text]pm/V at room temperature, which is competitive with the other BNT-based ceramics.

Effect of Buried Powder Sintering on the Electrical and Piezoelectric Properties of CuO-Modified (Li,K,Na)(Nb,Sb)O3 Lead-Free Piezoceramics

2016 ◽  
Vol 697 ◽  
pp. 211-215 ◽  
Author(s):  
Lin Ling Li ◽  
Yu Hua Zhen
Keyword(s):  
Piezoelectric Properties ◽  
Relative Dielectric Constant ◽  
Lead Free ◽  
Tetragonal Symmetry ◽  
Orthorhombic Symmetry ◽  
Conventional Solid State Reaction ◽  
Maximum Value ◽  
Powder Sintering ◽  
Sintering Method ◽  
Li Content

A strong desire for environmental protection and human health care urgently requires us to find an environmental friendly type of piezoelectric material to replace the lead ones. In this study, (LixK0.5-xNa0.5)(Nb0.97Sb0.03)O3-1mol%CuO (x = 0, 0.05, 0.1 ,0.2 ,0.5, abbreviated as CuO-LxKNNS) lead-free piezoelectric ceramics have been fabricated by a conventional solid-state reaction route. We focused on the comparison of buried powder sintering with exposed sintering. The effect of buried powder sintering method on density, structure and dielectric, piezoelectric properties of CuO-LxKNNS ceramics has been investigated. It was found that the density increased greatly when the buried powder sintering method was used, which was effective in inhibiting the volatilization of alkali metal oxides compared with exposed sintering method. Piezoelectric and dielectric properties showed a similar tendency with the density. These ceramics showed an obvious phase transition with increasing the Li content. CuO-LxKNNS ceramics showed orthorhombic symmetry when x= 0, but turned to be tetragonal symmetry when x ≥ 0.05. The optimal composition of CuO-LxKNNS with buried powder sintering method was x = 0.05 sintered at 1020 °C, for which the maximum value of the piezoelectric constant (d33) was 180pC/N, the density (ρ) was 4.40g/cm3, the room temperature relative dielectric constant (εr) was 270 and the dielectric loss (tanδ) was 0.07.

Temperature dependence of piezoelectric properties of 0.67 Pb(Mg1/3Nb2/3)O3–0.33 PbTiO3 single crystals

2003 ◽  
Vol 18 (2) ◽  
pp. 537-541 ◽  
Author(s):  
Ping-chu Wang ◽  
Xiao-ming Pan ◽  
Dong-lin Li ◽  
Yuan-wei Song ◽  
Hao-su Luo ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Temperature Dependence ◽  
Single Crystals ◽  
Phase Transition Temperature ◽  
Room Temperature ◽  
Piezoelectric Properties ◽  
Device Design ◽  
Temperature Range ◽  
Approach Zero

Piezoelectric properties k33 and d33 of 0.67 Pb(Mg1/3Nb2/3)O3–0.33 PbTiO3 single crystals grown by a modified Bridgman method were measured in the temperature range of 20–150 °C. Recoverability of the properties after the samples were heated to 110 °C, above the ferroelectric–ferroelectric (F–F) phase transition temperature of the composition, was found. From 20 to approximately 80 °C, k33 increases slightly, while d33 is almost doubled. Between approximately 90 and 100 °C, k33 decreases sharply to roughly a level of PZT-5 ceramics and d33 decreases to about 700 pC/N. They increase again with further increase of temperature; at 140 °C they attain 0.74 and approximately 1300 pC/N, respectively, and then decrease quickly and approach zero at about 150 °C. When heating to 110 °C followed by cooling to room temperature, the property decay is small. After more than one dozen heating–cooling cycles, k33 and d33 tend to be stable at 0.89 and approximately 1220 pC/N, respectively. The results might be helpful for device design and applications of PMN–PT single crystals.

Modified BiFeO3-PbTiO3 Morphotropic Phase Boundary (MPB) Piezoelectric Ceramics for High Temperature and High Power Applications

2003 ◽  
Vol 785 ◽  
Author(s):  
JinRong Cheng ◽  
L. Eric Cross
Keyword(s):  
Phase Boundary ◽  
Morphotropic Phase Boundary ◽  
Room Temperature ◽  
Piezoelectric Properties ◽  
Breakdown Strength ◽  
Critical Role ◽  
Rhombohedral Phase ◽  
Tetragonal Symmetry ◽  
Pzt Ceramics ◽  
Reduced Forms

ABSTRACTBiFeO3-PbTiO3 (BF-PT) crystalline solutions have been modified by La3+, Ga3+ and Ba2+ substituent. The modified BF-PT had morphotropic phase boundary (MPB), at which the ferroelectric rhombohedral phase transferred to the tetragonal symmetry. The piezoelectric properties at the MPB were strongly depended on different substituents. The modified BF-PT system showed the insulation resistivity up to 1012 ω·cm at room temperature. Lanthanum played a critical role making BF-PT softer to be poled to the piezoelectric state. Ga provided BF-PT additional polarization and breakdown strength with La substituent. In the system with La3+, Ga3+ and Ba3+ simultaneously, addition of Ba enhanced dielectric and piezoelectric activity. It was flexible to tailor BF-PT by using different substituents. In the vicinity of MPB, the Curie temperature Tc was above 385°C of BF-PT for La <10 at%, whereas the d33 constant was as high as 295 pC/N for one with La of 20 at%. The modified BF-PT revealed comparable performances to conventional Pb(Zr,Ti)O3 (PZT) ceramics, but in significantly lead reduced forms.

Microstructure Control of Barium Titanate – Potassium Niobate Solid Solution System Ceramics by MPB Engineering and their Piezoelectric Properties

2011 ◽  
Vol 485 ◽  
pp. 89-92 ◽  
Author(s):  
Shigehito Shimizu ◽  
Nobuhiro Kumada ◽  
Kouichi Nakashima ◽  
Ichiro Fujii ◽  
Daisuke Tanaka ◽  
...  
Keyword(s):  
Solid Solution ◽  
Room Temperature ◽  
Piezoelectric Properties ◽  
Potassium Niobate ◽  
Interface Area ◽  
Solution System ◽  
Solid Solution System ◽  
Conventional Sintering ◽  
Sintering Method ◽  
Dielectric And Piezoelectric Properties

Effect of the microstructural homogeneity of 0.5 BaTiO3 - 0.5 KNbO3 (0.5BT-0.5KN) solid solution ceramics on the dielectric and piezoelectric properties was investigated. Microstructure of a sample prepared by a conventional sintering method was homogenous, and the room temperature crystal structure was assigned to cubic Pm3m symmetry and therefore the sample was paraelectric. On the other hand, microstructure of samples prepared by a two-step sintering method was inhomogeneous, that is, it was made of BT and KN grains. The large electric field piezoelectric constant d33* increased with increasing interface area.

scholarly journals First experimental evidence of the piezoelectric nature of struvite

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jolanta Prywer ◽  
Rafał Kruszyński ◽  
Marcin Świątkowski ◽  
Andrzej Soszyński ◽  
Dariusz Kajewski ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Experimental Evidence ◽  
Heating Rate ◽  
Transformation Temperature ◽  
Room Temperature ◽  
Piezoelectric Coefficient ◽  
Piezoelectric Properties ◽  
Parallel Plates ◽  
Gel Growth ◽  
Growth Technique

AbstractIn this paper, we present the first experimental evidence of the piezoelectric nature of struvite (MgNH4PO4·6H2O). Using a single diffusion gel growth technique, we have grown struvite crystals in the form of plane parallel plates. For struvite crystals of this shape, we measured the piezoelectric coefficients d33 and d32. We have found that at room temperature the value of piezoelectric coefficient d33 is 3.5 pm/V, while that of d32 is 4.7 pm/V. These values are comparable with the values for other minerals. Struvite shows stable piezoelectric properties up to the temperature slightly above 350 K, for the heating rate of 0.4 K/min. For this heating rate, and above this temperature, the thermal decomposition of struvite begins, which, consequently, leads to its transformation into dittmarite with the same non-centrosymmetric symmetry as in case of struvite. The struvite-dittmarite transformation temperature is dependent on the heating rate. The higher the heating rate, the higher the temperature of this transformation. We have also shown that dittmarite, like struvite exhibits piezoelectric properties.

scholarly journals Thermal, Viscoelastic, Mechanical and Wear Behaviour of Nanoparticle Filled Polytetrafluoroethylene: A Comparison

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1940 ◽  
Author(s):  
Levente Ferenc Tóth ◽  
Patrick De Baets ◽  
Gábor Szebényi
Keyword(s):  
Room Temperature ◽  
Filler Content ◽  
Research Work ◽  
Tensile Modulus ◽  
Al2o3 Content ◽  
Wear Behaviour ◽  
X Ray ◽  
Mechanical Stirring ◽  
Wear Analysis ◽  
Sintering Method

In this research work, unfilled and mono-filled polytetrafluoroethylene (PTFE) materials were developed and characterised by physical, thermal, viscoelastic, mechanical, and wear analysis. The applied fillers were graphene, alumina (Al2O3), boehmite alumina (BA80), and hydrotalcite (MG70) in 0.25/1/4/8 and 16 wt % filler content. All samples were produced by room temperature pressing–free sintering method. All of the fillers were blended with PTFE by intensive dry mechanical stirring; the efficiency of the blending was analysed by Energy-dispersive X-ray spectroscopy (EDS) method. Compared to neat PTFE, graphene in 4/8/16 wt % improved the thermal conductivity by ~29%/~84%/~157%, respectively. All fillers increased the storage, shear and tensile modulus and decreased the ductility. PTFE with 4 wt % Al2O3 content reached the lowest wear rate; the reduction was more than two orders of magnitude compared to the neat PTFE.

scholarly journals Computational Intelligence Approach for Estimating Superconducting Transition Temperature of Disordered MgB2Superconductors Using Room Temperature Resistivity

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Taoreed O. Owolabi ◽  
Kabiru O. Akande ◽  
Sunday O. Olatunji
Keyword(s):  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Room Temperature ◽  
Optimization Technique ◽  
Support Vector ◽  
Measuring Instruments ◽  
Room Temperature Resistivity ◽  
Superconducting Transition ◽  
Experimental Values ◽  
Temperature Resistivity

Doping and fabrication conditions bring about disorder in MgB2superconductor and further influence its room temperature resistivity as well as its superconducting transition temperature (TC). Existence of a model that directly estimatesTCof any doped MgB2superconductor from the room temperature resistivity would have immense significance since room temperature resistivity is easily measured using conventional resistivity measuring instrument and the experimental measurement ofTCwastes valuable resources and is confined to low temperature regime. This work develops a model, superconducting transition temperature estimator (STTE), that directly estimatesTCof disordered MgB2superconductors using room temperature resistivity as input to the model. STTE was developed through training and testing support vector regression (SVR) with ten experimental values of room temperature resistivity and their correspondingTCusing the best performance parameters obtained through test-set cross validation optimization technique. The developed STTE was used to estimateTCof different disordered MgB2superconductors and the obtained results show excellent agreement with the reported experimental data. STTE can therefore be incorporated into resistivity measuring instruments for quick and direct estimation ofTCof disordered MgB2superconductors with high degree of accuracy.

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