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B. Wodecka-Duś and D. Czekaj

Synthesis of 0.7BiFeO3-0.3BaTiO3 Ceramics: Thermal, Structural and AC Impedance Studies

In a present paper results of the process of synthesis and study of a perovskite-type solid solution of the chemical composition (1-x)BiFeO3-xBaTiO3 for x=0.3 are reported. Synthesis of 0.7BiFeO3-0.3BaTiO3 (BF-BT) ceramics was carried out according to the solid-phase reaction from the mixture of powders. Simultaneous thermal analysis (STA) and X-ray diffraction method were utilized to study the synthesis of BF-BT ceramics. On the basis of STA analysis the optimum conditions of the thermal treatment were found. BF-BT ceramics was studied in terms of its microstructure (SEM), chemical composition (EDS), crystalline structure (XRD), and dielectric properties (impedance spectroscopy) at room temperature. It was found that dense BF-BT ceramics with a cubic structure of Pm3m space group and desired stoichiometry (±3%) was fabricated under technological conditions differing in both sintering temperature (T=750°C-850°C) and soaking time (t=2h-40h). It was found that an increase in sintering temperature for ΔT=100°C made it possible to decrease the soaking time 10 times. Impedance spectroscopy was utilized for characterizing dynamical dielectric properties of 0.7BF-0.3BT ceramics. The alternative representation of impedance data in a form of complex plot (Z" vs. Z') as well as simultaneous Bode plots (imaginary parts of impedance Z", admittance Y", electric modulus M" and tanΔ versus frequency in a log-log scale) were used for preliminary visual analysis. Kramers-Kronig transform test was utilized for experimental data validation. To analyze the room temperature impedance spectroscopy data complex nonlinear least squares fitting method was used and the data were fitted to the corresponding equivalent circuit consisting of resistors and constant phase elements. Agreement between experimental and simulated data was established.

Open access

B. Wodecka-Duś, M. Plońska and D. Czekaj

Abstract

In the present study BaTiO3 and Ba1-xLaxTiO3 (0.1-0.4mol.% La) ceramic powders were synthesized by the conventional mixed oxide method (MOM). The characterization of the ceramic powders was carried out using a simultaneous thermal analysis (STA), with a combined DTA/TG/DTG system (Netzsch STA409). The results of thermal analysis allowed to determine the optimal temperature of synthesis. Microstructure was investigated by scanning electron microscopy (SEM), crystalline structure was studied by X-ray diffraction method (XRD). The EDS investigations showed that samples exhibited conservation of stoichiometry according to the chemical composition formula. The X-ray diffraction analysis confirmed formation of the desired crystalline structure both pure and La3+-doped BaTiO3 ceramics exhibiting a perovskite-type structure ABO3 with tetragonal symmetry P4 mm.

Open access

M. Płonska, W.A. Pisarski, B. Wodecka-Dus and D. Czekaj

Abstract

The aim of this work was to study the effect of fabrication conditions and neodymium co-doping on the physical properties of (Pb0:98La0:02)(Zr0:65Ti0:35)0:98O3, known as PLZT:Nd3+ ceramics. All ceramic powders of these materials were synthesized by the conventional mixed oxide method, from the high purity raw materials (>99.9%). The bulk ceramic samples were sintered by the pressure less sintering and the hot-uniaxial pressing techniques. The study gives a detailed account of the relationships between doping and preparing conditions on the dielectric and optical properties of obtained ceramic materials. Optimal conditions of PLZT:Nd3+ preparation as well as Nd3+ activator concentration were determined in relation to the potential opto-electronic applications.

Open access

B. Wodecka-Dus, L. Kozielski, J. Erhart, M. Pawełczyk, D. Radoszewska, M. Adamczyk and D. Bochenek

Abstract

Effects of La3+ admixture in barium lanthanum titanate (BLT) ceramics system with colossal permittivity on performance of prospective piezoelectric cold plasma application were studied. Usage of cold atmospheric pressure plasma appears promising in terms of industrial and healthcare applications. Performed investigation provide consistent evaluation of doping lanthanum amount on piezoelectric coefficients values with simultaneous capability of charge accumulation for effective plasma generation. Modification of ferroelectric materials with heterovalent ions, however with the lower radii than the original atoms, significantly affects their domain mobility and consequently electromechanical properties. To determine the piezoelectric coefficients, the resonance-antiresonance method was implemented, and values of piezoelectric and dielectric parameters were recorded. Finally the results indicated that addition of 0.4 mol.% of La3+ ions to the ceramic structure maximally increased the values of piezoelectric coefficient to d 33 = 20 pC/N and to huge dielectric constant to ε 33 T = 29277.

Open access

B. Wodecka-Dus, M. Adamczyk, T. Goryczka, J. Dzik, D. Radoszewska, L. Kozielski and D. Bochenek

Abstract

The present paper widely describes the details of technology of (Ba0.6Pb0.4)TiO3 ceramics modified with PbO-B2O3-Al2O3-WO3 special glass, as well as the influence of admixture on the microstructure and crystal structure of basic material. The microstructure investigations reveal the significant increase of grain size and a decrease of pores participation in volume of modified samples, whereas the X-Ray Diffraction (XRD) measurements show a decrease of the volume of unit cell. The obtained results are discussed due to processes occurring during the sintering process at high temperature.

Open access

D. Bochenek, P. Niemiec, M. Adamczyk, R. Skulski, R. Zachariasz, B. Wodecka-Duś and Z. Machnik

Abstract

In the paper two compositions of the multi-component PZT-type ceramics admixtures by Mn4+, Sb3+, W6+, Ni2+ were presented. The ceramic powders were synthesized by the calcination of powders while their densification was carried out by free sintering method. The dielectric, ferroelectric, piezoelectric studies and DC electrical conductivity of the multicomponent PZT-type samples were presented. The results of the multi-component ceramics predispose these type materials in micromechatronic and microelectronic applications for example as element of the actuators.

Open access

M. Adamczyk, J. Kusz, W. Hofmeister, M. Zubko, L. Kozielski, M. Pilch, D. Bochenek and B. Wodecka-Duś

Abstract

The subject of the paper is lead free bismuth layer structure oxides (1-x)Bi3TiNbO9-xBaBi2Nb2O9 (x=0; 1; 2; 3 mol). The influence of Bi3TiNbO9/BaBi2Nb2O9 ratio on dielectric and structural properties was studied in a wide range of temperatures. Change in the ratio causes a decrease in the maximum value of dielectric permittivity and shifts the temperature of ε’max to low values, leading to linear decreasing of average grain size and linear increasing of ceramics density. These results indicate an augment of the packing degree and the participation of pores are significantly decreased with the increase of BaBi2Nb2O9 compound intake. Moreover, for 0.7Bi3TiNbO9-0.3BaBi2Nb2O9 ceramics the dielectric phase transition is broadened and the properties characteristic for the ferroelectric relaxor appear.