A5063020452- Ferroelectric and Piezoelectric Materials
- Multiferroics and related materials
- Microwave Dielectric Ceramics Synthesis
- Acoustic Wave Resonator Technologies
- Advanced Thermoelectric Materials and Devices
- Perovskite Materials and Applications
- Dielectric properties of ceramics
- Semiconductor materials and interfaces
- Electronic and Structural Properties of Oxides
- Chalcogenide Semiconductor Thin Films
- Heusler alloys: electronic and magnetic properties
- Thermal properties of materials
- Nuclear Materials and Properties
- ZnO doping and properties
- Advanced materials and composites
- Photorefractive and Nonlinear Optics
- Fusion materials and technologies
- Magnetic and transport properties of perovskites and related materials
- Phase-change materials and chalcogenides
- Intermetallics and Advanced Alloy Properties
- Magneto-Optical Properties and Applications
- Gas Sensing Nanomaterials and Sensors
- Dielectric materials and actuators
- Advanced Thermodynamics and Statistical Mechanics
- Material Selection and Properties
Donghua University
2016-2024
China National Petroleum Corporation (China)
2023
Queen Mary University of London
2009-2020
Nanoforce Technology (United Kingdom)
2009-2020
State Council of the People's Republic of China
2020
Mile End Hospital
2020
Fudan University
2018
Transnational Press London
2015
Materials Center Leoben (Austria)
2013
Tallinn University of Technology
2012
Commercial lead-based piezoelectric materials raised worldwide environmental concerns in the past decade. Bi₀.₅Na₀.₅TiO₃-based solid solution is among most promising lead-free candidates; however, depolarization of these solutions a longstanding obstacle for their practical applications. Here we use strategy to defer thermal depolarization, even render depolarization-free 0-3-type composites. This achieved by introducing semiconducting ZnO particles into relaxor ferroelectric...
Triangular voltage waveform was employed to distinguish the contributions of dielectric permittivity, electric conductivity and domain switching in current-electric field curves. At same time, it is shown how those can affect shape displacement — loops (D–E loops). The effects frequency, temperature microstructure (point defects, grain size texture) on ferroelectric properties several compositions reported, including: BaTiO 3 ; lead zirconate titanate (PZT); lead-free Na 0.5 K NbO...
The perovskite‐like layer‐structured (PLS) Nd 2 Ti O 7 and La have possibly the highest Curie points of any materials. To pole these ceramics, highly textured, dense ceramics with high DC electrical resistivity are required. ferroelectric piezoelectric properties lead‐free grain‐oriented prepared by spark plasma sintering using a two‐step method reported. T c 1482±5° 1461±5°C, respectively. measured constant textured was d 33 =2.6 pC/N. These results now open up possibility studying...
In 0.95[0.94Bi0.5Na0.5TiO3-0.06BaTiO3]-0.05CaTiO3 ceramics, the temperature TS (dielectric permittivity shoulder at about 125 °C) represents a transition between two different thermally activated dielectric relaxation processes. Below TS, approximately linear decrease of with logarithm frequency was attributed to presence dominant ferroelectric phase. Above shows more complicated dependence and Raman modes indicate sudden increase in spatial disorder material, which is ascribed nonpolar...
The perovskite‐like layer structured strontium niobate (Sr 2 Nb O 7 ) and calcium (Ca are good candidates for high‐temperature piezoelectric applications because of their high Curie points. Single‐phase dense Sr Ca ceramics with grain‐oriented microstructures were prepared by spark plasma sintering using a two‐step method. Lotgering orientation factors 0.86 0.70 , respectively. T c measured as 1327±5°C above 1525°C, dielectric, piezoelectric, ferroelectric properties, direct‐current...
The porous Mg<sub>2</sub>(Si, Sn) sample pressure-lessly sintered at 1123 K by SPS with a porosity of 37% showed an enhanced maximum <italic>zT</italic> = 1.63 615 K.
Abstract The effects of temperature and electric field-induced structural modifications on the energy storage properties 0.95[0.94Bi 0.5 Na TiO 3 –0.06BaTiO ]–0.05K NbO (BNT–BT–5KNN) ceramics were investigated. X-ray diffraction performed unpoled poled in range 25–500 °C suggested an increment rhombohedral phase intensity peaks tetragonal distortion after electrical poling. content reduced with increasing both ceramics. In ceramic, eventually disappeared, while it survived specimen up to 500...
Ferritic steels strengthened with Ti–Y–O nanoclusters are leading candidates for fission and fusion reactor components. A Fe–14Cr–0.4Ti + 0.25Y2O3 (14YT) alloy was fabricated by mechanical alloying subsequently consolidated spark plasma sintering (SPS). The densification of the 14YT alloys significantly improved an increase in temperature. Scanning electron microscopy backscatter diffraction revealed that SPS-sintered at 1150 °C under 50 MPa 5 min had a high density (99.6%), random grain...
Large <italic>ZT</italic> enhancement (50%) is obtained in hot forged nanostructured p-type Bi<sub>0.5</sub>Sb<sub>1.5</sub>Te<sub>3</sub> bulk alloys.
Piezoelectric ceramics of the composition Na 0.5 K NbO 3 (NKN) with grain sizes in range 0.2–1 μm were fabricated by spark plasma sintering. Ferroelectric domain size decreases decreasing and non‐180° ferroelectric domains walls still visible 200 nm sized grains. The Curie point was independent. This suggests that critical for a single structure NKN is <200 nm. Optimized processing conditions enabled high densities (>99.5% theoretical density) to be made at T ≥850°C. For dense (grain...
The effect of strontium substitution on structural, magnetic, and dielectric properties a multiferroic Y-type hexaferrite (chemical formula Ba2−xSrxMg2Fe12O22 with 0 ≤ x 2) was investigated. phase formation not affected by for barium, in the range 1.5, confirmed x-ray diffraction Raman spectroscopy measured at room temperature. Two intermediate magnetic spin transitions (at tempertures TI TII) ferrimagnetic-paramagnetic transition Curie temperature TC) were identified from dependence...
Ferroelectricity and piezoelectricity in CsBiNb<sub>2</sub>O<sub>7</sub>are demonstrated for the first time.
AbstractThe perovskite-like layer structured praseodymium titanate (Pr2Ti2O7; PTO) is a good candidate for high temperature piezoelectric application because of its Curie point. Single phase, dense, textured PTO ceramic was prepared by spark plasma sintering using two-step method the first time. The Lotgering orientation factor 0·87. point >1555±5°C. dielectric constant increases with grain size due to decreasing effect boundaries and increasing extrinsic contribution from ferroelectric...
Aurivillius phase, bismuth layer structured ferroelectric Bi3.15Nd0.85Ti3O12 (BNdT) ceramics with average grain sizes from 90 nm and high densities (>97%) were fabricated by spark plasma sintering. Decreasing size produced a diffuse ferro–paraelectric phase transition decrease in the Curie point. Compared BNdT of micrometre scale, nanograined exhibit depression dielectric maximum at point, enhanced constant room temperature to 350 °C dramatically decreased losses. Although switching was...
The microscopic origin of the grain size effects on dielectric, piezoelectric, and thermal depoling properties Aurivillius phase Bi3.15Nd0.85Ti3O12 was investigated. Using atomic force microscopy, domain walls were observed in micrometer ceramics, but gradually disappeared with reducing not found ceramics 90 nm size. In strain-electric field butterfly loops, strain decreased decreasing indicating a contribution non-180° switching to strain. Lattice distortion (a−b)/b resistance size, due...
A nanoscale core-shell NiO@CoO composite is prepared on flexible carbon cloth for electrodes in supercapacitors and overall water splitting. The needle-like CoO nanowires with NiO nanosheets as the active materials improve elemental constituents well surface area. electrode boasts a capacity of 2.87 F cm-2 (1024.05 g-1) at 1 g-1 current density, even large density 20 retention ratio 80.9% after 5000 cycles. excellent specific high rate capability can be ascribed to unique structure which...
This work revealed that the solid solution compounds of Sr 2 − x Ba Nb O 7 are promising lead‐free materials for high‐temperature piezoelectric sensor application. These were confirmed as ferroelectric with high Curie points ( > 900°C) by their activity after poling, domain switching in P – E hysteresis loops and thermal depoling behavior. The effect substitution on structure properties < 1.0) was investigated. limit determined XRD 0.6. a ‐, b c ‐ axes, cell volume increase addition....
Tellurium based glasses have interesting thermoelectric characteristics. However, their high electrical resistivity is still an obstacle to considering them for applications. In this work, the (Te85Se15)60 − 0.6xAs40 0.4xCux glass system was studied. This revealed that Cu can act as former and increase both thermal stability conductivity. The best candidate, (Te85Se15)45As30Cu25, chosen prepare composites with Bi0.5Sb1.5Te3 using spark plasma sintering. These ceramic samples exhibited a much...
Single‐phase bismuth tungstate (Bi 2 WO 6 ) ceramics with high relative density (>99%) were fabricated by spark plasma sintering. Ferroelectric, dielectric, and piezoelectric properties of Bi investigated. Almost saturated polarization–electric field ( P – E hysteresis loops a remanent polarization r ∼16.1 μC/cm coercive c ∼3.7 kV/mm obtained. Curie point second phase transition temperatures observed at 937°±5° 665°±5°C, respectively. The average constant d 33 this ceramic is 15±0.2 pCN −1 .