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Structural, dielectric and AC conductivity studies on 0.8Ba0.2(Bi0.5K0.5)Ti1-xZrxO3 lead free ceramic system

Ramesh M. N. V., Ramesh K. V.

Materials Science Poland

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2016

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Vol. 34, No. 3

669--675

EN

Zr substituted 0.8BaTiO30.2 Bi0,5 K0,5 TiO3 lead free ceramic materials with a composition 0.8Ba0.2(Bi0,5 K0,51-xZrxO3 (0.01 ≤x ≤0.06) were prepared by conventional solid state reaction method followed by high energy ball milling. The X-ray diffraction studies confirmed the tetragonal structure of the material at room temperature. Density was decreasing with the substitution of Zr. Microstructure studies were done by using scanning electron microscope. Temperature and frequency dependent dielectric studies were carried out and showed that the dielectric constant, dielectric loss and Curie temperature were decreasing with the substitution of Zr. Relaxor behavior was observed in all the Zr substituted samples. Degree of diffuseness was calculated from the modified Curie-Weiss law and it was found to increase with the substitution of Zr. Frequency and temperature dependent AC conductivity was calculated and it was found to obey Jonscher’s power law. Substitution of Zr decreased the conductivity of the material. Activation energy was calculated and it was decreasing with an increase in Zr substitution.

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The structure and optical properties of lead-free transparent KNLTN-La0.01 ceramics prepared by conventional sintering technique

Yang W L, Xiu H J, Xiong Y L, Wang J, Yuan C X, Wei J, Zhou Z X

Materials Science Poland

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2014

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Vol. 32, No. 4

597--603

EN

(Na0.52K0.44Li0.04)0.97La0.01Ta0.20Nb0.80O3 (KNLTN–La0.01) lead-free subtransparent ceramics was prepared by a conventional sintering technique. The structure and the optical properties of the ceramics were investigated. The room temperature crystallographic indexing revealed the ABO3 perovskite type, tetragonal phase and P4mm point group in the ceramics. The surface and fractured surface SEM micrographs showed a dense microstructure with few micropores in KNLTN–La0.01 ceramics, which was obviously better than for the pure KNLTN ceramics. The refractive indexes of the films were investigated by an ellipsometer and the results show that the KNLTN–La0.01 subtransparent ceramics reveals significant wavelength dependent dispersion. The refractive index ranges from 2.14 to 2.06 with the wavelength increase from 380 nm to 900 nm. The dispersive behavior was analyzed by three parameters of Cauchy dispersion model and the values of the parameters A, B and C are 2.0610±0.0005, 0.0054±0.0003 and 0.00069±0.00004, respectively.

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The effects of sintering temperature and poling condition on the piezoelectric properties of 0.935(Bi0.5Na0.5)TiO3 - 0.065BaTiO3 ceramics

Lidjici H., Rguiti M., Hobar F., Trelcat J. F., Courtois C., Leriche A.

Materials Science Poland

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2011

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Vol. 29, No. 1

9--14

EN

The 0.935(Bi0.5Na0.5) TiO3 -0.065BaTiO3 (abbreviated as BNT6.5BT) lead-free ceramics were prepared by conventional solid state sintering technique. The effects of sintering temperature (1150-1200 °C) and poling condition on its piezoelectric properties were examined. Piezoelectric properties like the piezoelectric constant (d33) and electromechanical factors (kp, kt) depend on the poling field and poling temperature, whereas different poling times, in the 5-30 min range, were not observed to have any significant effect on the piezoelectric properties. With respect to piezoelectric properties, the chosen sintering temperature range is suitable for BNT6.5BT ceramics.

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Lead - free ferroelectric titanate ceramics

Zaremba T.

Polish Journal of Chemical Technology

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2006

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Vol. 8, nr 3

147-149

EN

The synthesis of K0.5Bi0.5TiO3 (KBT) and Na0.5Bi0.5TiO3 (NBT) was performed by heating the mixtures prepared using oxide precursors, i.e. Bi2O3, TiO2 , K2CO3 and Na2CO3. The sintering behaviour of the prepared powders was studied. The effect of the sintering temperature on the densification process of the sintered ceramics and their microstructures were investigated.