EVALUATION OF SOME DIELECTRIC MATERIALS PREPARED BY SOLID-STATE REACTION
SHAIMAA MOHAMMAD MOHAMMAD BEHERY;
Abstract
The solid solution of PbZr 1_,Ti,03, known as lead-zircon ate titanate (PZT), was probably one of the most important ferroelectric materials, especially due to its excellent dielectri-c, ferroelectric and piezoelectric properties. The highest piezoelectric coefficients of the PZT are found near the morphotropic phase boundary (MPB) (0.46 S x S 0.49), between the tetragonal and rhombohedral regions of the composition-temperature phase diagram.
In the present work, the formation mechanism of Pb(Zro_ 52Ti0_.8)03 : PZT solid solution prepared by the mixed oxides techniques consisting of Pb02, Ti02 and Zr02 was studied by X ray diffraction (XRD), differential thermal analysis (DTA) and thermo-gravimetric analysis
(TGA).. The first step is the decomposition of Pb02 to PbO. The second step, above 500 °C, is the reaction of reactive PbO and TiO, to form PbTi0 3 . When the saturated PbTi03 is submitted to a temperature increase, the interaction of PbO, Zr0 2 and Ti02 inside the PbTi03 perovskite forming the PZT solid solution takes places. The optimum temperature of calcination for the
formation of pure perovskite phase, was found about 800 °C for 2 h with a heating rate of 5
°C/min.
The sintering procedures were carried out at 900, 1000, I I 00, 1200 °C for 4 h with a heating rate of 5 °C/min. The XRD pattern of the sintered PZT ceramics showed a coexistence of
tetragonal and rhombohedral phases. The density of the ceramics reaches a maximum value of
3
7.62 g!cm
at II 00 °C and the average grain size increases with increasing sintcring temperature.
The dielectric properties and the piezoelectric coefficients d33 increase with increasing sintering temperature and grain size. From a hysteresis study, the remanent polarization (P,) and coercive field (£,) of PZT ceramic sintered at 1200 °C are observed to be 45 uC/cm2 and 16 kV
em·', respectively. The value of P, increases and E, decreases with increasing the temperature of sintering.
Key words: Solid-State , PZT, ferroelectric properties .
In the present work, the formation mechanism of Pb(Zro_ 52Ti0_.8)03 : PZT solid solution prepared by the mixed oxides techniques consisting of Pb02, Ti02 and Zr02 was studied by X ray diffraction (XRD), differential thermal analysis (DTA) and thermo-gravimetric analysis
(TGA).. The first step is the decomposition of Pb02 to PbO. The second step, above 500 °C, is the reaction of reactive PbO and TiO, to form PbTi0 3 . When the saturated PbTi03 is submitted to a temperature increase, the interaction of PbO, Zr0 2 and Ti02 inside the PbTi03 perovskite forming the PZT solid solution takes places. The optimum temperature of calcination for the
formation of pure perovskite phase, was found about 800 °C for 2 h with a heating rate of 5
°C/min.
The sintering procedures were carried out at 900, 1000, I I 00, 1200 °C for 4 h with a heating rate of 5 °C/min. The XRD pattern of the sintered PZT ceramics showed a coexistence of
tetragonal and rhombohedral phases. The density of the ceramics reaches a maximum value of
3
7.62 g!cm
at II 00 °C and the average grain size increases with increasing sintcring temperature.
The dielectric properties and the piezoelectric coefficients d33 increase with increasing sintering temperature and grain size. From a hysteresis study, the remanent polarization (P,) and coercive field (£,) of PZT ceramic sintered at 1200 °C are observed to be 45 uC/cm2 and 16 kV
em·', respectively. The value of P, increases and E, decreases with increasing the temperature of sintering.
Key words: Solid-State , PZT, ferroelectric properties .
Other data
| Title | EVALUATION OF SOME DIELECTRIC MATERIALS PREPARED BY SOLID-STATE REACTION | Other Titles | تقييم بعض المواد العازلة المحضرة بالتفاعلات في الحالة الصلبة | Authors | SHAIMAA MOHAMMAD MOHAMMAD BEHERY | Issue Date | 2010 |
Attached Files
| File | Size | Format | |
|---|---|---|---|
| SHAIMAA MOHAMMAD MOHAMMAD BEHERY.pdf | 1.43 MB | Adobe PDF | View/Open |
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