0000000000185955
AUTHOR
M. Sokolowski
Influence of Electromechanical Fields on Dielectric Properties of PLZT−x/65/35 Ceramics (x = 6 and 7)
High density and transparent PLZT−x/65/35 (x = 6 and 7) ceramics with the average grain size of 5–7 μm was obtained by two−stage hot−pressing technology. The measurements of temperature/frequency dependence of the permittivities of these ceramics under uniaxial pressure (0–100 MPa) applied parallel to the ac electric field have been carried out. It was found that uniaxial pressure significantly influences dielectric properties of these ceramics. With the increase of pressure the maximum intensity in ϵ(T) curve decreases, becomes more diffuse and shifts towards higher temperature, dielectric dispersion decreases and classical ferroelectric seems to change to relaxor one. It was concluded, th…
Dielectric Properties of Na0.5K0.5(Nb1-xSbx)O3+MnO2 Ceramics (x = 0.04, 0.05 and 0.06)
Lead-free ceramics Na0.5K0.5(Nb1-xSbx)O3+0.5mol%MnO2 (x = 0.04, 0.05 and 0.06) were prepared by conventional sintering and hot pressing process; their microstructure and dielectric properties have been studied. It is found that increase of sintering temperature promotes the obtaining highly dense microstructure and increase in grain size while doping with Sb contributes to more dense and homogeneous microstructure and smaller grain size. Low frequency (100 Hz-200 kHz) investigations revealed the diffuse phase transitions. It can be concluded from experimental results that Sb doping improves dielectric properties. The obtained materials are expected to be promising candidates for lead-free e…
Dielectric and Ferroelectric Properties of Lead-Free NKN and NKN-Based Ceramics
Lead-free ceramics of Na0.5K0.5NbO3 (NKN), Na0.5K0.5(Nb0.94Sb0.06)O3 (NKNS6) and Na0.5K0.5(Nb0.94Sb0.06)O3 + 0.5%MnO2 (NKNS6 + 0.5%MnO2) have been prepared by a solid phase hot pressing sintering process. X-ray diffraction results show that the obtained samples possess the perovskite structure. The micrograph of the fractured surface showed a dense structure in a good agreement with that of 91–94% relative density determined by the Archimedes method. An average grain size decreases with Sb and Mn doping (from about 20 μm for NKN to about 5 and 2 μm for NKNS6 and NKNS6 + 0.5%MnO2, respectively). Low frequency (100 Hz–200 kHz) investigations revealed the diffuse phase transitions. It was foun…
PLZTx/65/35 ceramics (x = 2 and 4) under electromechanical and temperature loading
The effect of uniaxial pressure (0–1000 bars) applied parallel to the ac electric field on dielectric properties of La-modified lead–zirconate–titanate, Pb(Ti,Zr)O3 (PZT), ceramics with Zr/Ti ratio of 65/35 was investigated. The experimental results revealed that applying uniaxial pressure leads to a reduction of the peak intensity of the electric permittivity (e), of the frequency dispersion as well as of the dielectric hysteresis. Moreover, with increasing pressure, the peak intensity of e becomes diffuse and shifts to a higher temperature. It was concluded that applying uniaxial pressure induces similar effects as increasing the Ti–ion concentration in PZT system. The obtained results we…
Influence of uniaxial pressure and aging on dielectric and ferroelectric properties of BaTiO3ceramics
The effect of uniaxial pressure (0–3000 bar) applied parallel to the AC electric field and aging on dielectric and ferroelectric behavior of BaTiO3 ceramics were investigated. Applying uniaxial pressure leads to a reduction of the peak intensity of the electric permittivity (e) of the polarization as well as of the dielectric hysteresis. The peak intensity of e becomes diffused and shifts to a higher temperatures with increasing the pressure. The electrostrictive coefficient Q 11 and differential permittivity were evaluated from the obtained data. We interpreted our results based on the hardening of the soft-mode and domain switching processes under the action of pressure. The aging effect …