A Microstructure, Piezoelectric and Dielectric Properties of the PZT Ceramics Obtained by the Sol-Gel Method

A technological process to obtain ceramic materials by the sol-gel method replaces gradually conventional methods, based on a simple oxide synthesis as a result of high temperature sintering. The materials obtained by the sol-gel method are characterized by high density and better chemical purity. A powder with the Pb(Zr0:52Ti0:48)O3 chemical composition was obtained as a result of a synthesis by the sol-gel method and it was formed and sintered by a hot pressing method (HP). The specimens obtained were subjected to examinations of the dielectric properties, the tangent of dielectric loss angle, the piezoelectric properties and their micro-photographs were taken (SEM). A course of the technological process by the sol-gel method was described, the dielectric and piezoelectric parameters were determined and a microstructure and a domain structure were examined in the work

Dielectric and piezoelectric properties of PZT type ceramics obtained by the sol-gel method

A sol-gel method belongs to chemical methods of producing non-organic and nonmetallic materials. As a result of a synthesis by the sol-gel method a powder with the Pb(Zr0.35Ti0.65)O3 chemical composition, which was formed and sintered freely, and hot pressed as well, was obtained. The obtained ceramic material was subjected to test of properties of permittivity, loss tangent and piezoelectric properties as well. Both a description of a technological process to obtain ceramic materials by the sol-gel method and the determined dielectric and piezoelectric parameters of the ceramic in question are presented in this work. The ceramic in question can be used, among others, in pressure sensors, electroacoustic transducers, piezoceramic amplifiers, loudspeakers and microphones

LMO ceramics microstructure

The aim of this work was to characterize the microstructure of LMO type ceramics. The ceramics obtained by the free sintering at two temperatures 1473 K and 1573 K and two sintering times 6 and 12 h was the test material. One series was also obtained by the hot pressing method for a comparison. In all the cases the material synthesis was conducted by the solid-state reaction method at 1173 for 24 h. Photographs of the specimen fractures were taken by a scanning electron microscope to characterize the microstructure of the ceramics obtained in a more detailed way. The VISILOG 4 system, enabling to calculate a lot of parameters characterizing the material microstructure, such as e.g.: a number of grains on the unit area, an average grain size, shape indexes of the grains in question, was used as well. It allows determining a grain size distribution, and a frequency of presence of grains with the specific shape index. By analyzing a set of the parameters obtained an influence of the technological conditions on the microstructure of the material in question, and on its properties and applicability at the same time can be determined

Study of phase and chemical composition of Bi1-xNdxFeO3 powders derived by pressureless sintering

In the present paper studies on Bi1-xNdxFeO 3 for x =0.1-0.4 are reported. The mixed oxide method followed with pressureless sintering was employed for ceramics fabrication. Thermal behavior of stoichiometric mixtures of simple oxide powders, viz. Bi2O 3, Nd2O3 and Fe2 O3 was studied by simultaneous thermal analysis. It was found that with an increase in neodymium content the weight loss increased from 0.75% to 3.16% for x =0.1 and x =0.4, respectively. It was found that weight loss took place mainly within two temperature ranges, namely △T1 ≈(300-400)°C and △T2 ≈600-800)°C. Bi 1-xNdxFeO3 ceramics was studied in terms of its phase composition (X-ray phase analysis) and chemical composition (EDS method) at room temperature. It was found that Bi1-xNdxFeO 3 suffered structural phase transition from rhombohedral to orthorhombic symmetry with an increase in neodymium concentration x within the range x =(0.2-0.3)

Influence of Calcium ions on the structure and properties of LaMnO3

La0,7Ca0,3MnO3 polycrystalline were synthesized from La2O3, CaO and MnO2 powder mixture using a solid state reaction technique. The compound powders were obtained through the free sintering method at different temperatures and sintering times in order to study the influence of technological conditions on Ca doped La manganites. The most important physical features as structure, microstructure and morphology were described after X-ray diffraction investigation. Photographs of the specimen fractures were taken with SEM (scanning electron microscope) and they revealed high porosity of the tested material and great tendency for its grains to create agglomerates. Influence of doping and technological conditions on lattice parameters were studied by means of Rietvield analysis. The XRD measurements reveal that La0,7Ca0,3MnO3 has orthorhombic symmetry with Pnma space group

Study of Phase and Chemical Composition of Bi1-xNdxFeO3 Powders Derived by Pressureless Sintering

In the present paper studies on Bi1-xNdxFeO 3 for x =0.1-0.4 are reported. The mixed oxide method followed with pressureless sintering was employed for ceramics fabrication. Thermal behavior of stoichiometric mixtures of simple oxide powders, viz. Bi2O 3, Nd2O3 and Fe2 O3 was studied by simultaneous thermal analysis. It was found that with an increase in neodymium content the weight loss increased from 0.75% to 3.16% for x =0.1 and x =0.4, respectively. It was found that weight loss took place mainly within two temperature ranges, namely △T1 ≈(300-400)°C and △T2 ≈600-800)°C. Bi 1-xNdxFeO3 ceramics was studied in terms of its phase composition (X-ray phase analysis) and chemical composition (EDS method) at room temperature. It was found that Bi1-xNdxFeO 3 suffered structural phase transition from rhombohedral to orthorhombic symmetry with an increase in neodymium concentration x within the range x =(0.2-0.3)