Radosław Zachariasz

Influence of the Technology Conditions on the Mechanical and Dielectric Properties of the PZT-Base Piezoceramic Transducers

Application of the piezoceramics produced on the base of the PZT-type s olid solution in modern electroacoustics depends primary on its mechanical and electr ica pa ameters. Multicomponent ceramic materials of the PZT-type are characterized by the occurrence of the morphotrophy area, it means the area of the rhombohedral and tetragonal phase coexistence. T he position and width of the area depends on the solid chemical solution and the technology used for obtai ning it. Therefore, selecting the suitable methods and conditions for producing piezoceramics is very impo tant since it has a direct influence on its properties. This work presents results of the investigations of the piezocerami c samples of the PZT-type received by the hot pressing method and the conventional sintering in different condi ions. The results obtained will be used to optimize the technological process and will indicate possibilities of wider applications of PZT-type piezoceramics in modern technology. Introduction Apart from the chemical composition and microstructure of ferroelec tric eramics temporary and temperature stability of their mechanical and dielectric param eters constitute important factors influencing their range of application. This has been confirmed by invest gations of the multicomponent solid state solutions of the PZT-type, conducted by differ ent methods [1 6]. Mechanical spectroscopy due to its high sensitivity to changes taking place in the real structure of materials has been more often used in recent investigations [6]. To observe changes occurring in the domain structure and to determine the stability of mechanical and die lectric parameters, the application of mechanical spectroscopy and the resonance-anti-resonance method is used. The influence of the conditions of the technological process on the stabil ity of temperature, on the mechanical properties and on the basic dielectric parameters of t he multicomponent piezoelectric ceramics of the PZT-type is shown. These investigations were ai m d at controlling the manufacturing process of ceramics to be used in ultrasound generators of high power e ngines and in piezoelectric transformers. Experimental The material used in this study was the ceramics belonging to te rnary solid solutions of the PZT-type with the following chemical composition: Pb (Zr 0.51 Ti0.49) O3 + Pb (Nb0.5 Mn0.5) O3 + 2.15 wt % Bi 2O3; its dielectric parameters show that it belongs to ceramics of medium ferroe lect ic hardness. The ceramics was obtained in different technological conditions by the hot pressing method in nitrogen or in argon atmosphere, and by the classical sintering method. A synthesized powder of the Solid State Phenomena Online: 2003-02-13 ISSN: 1662-9779, Vol. 89, pp 303-308 doi:10.4028/www.scientific.net/SSP.89.303

Structure and physical properties of PZT-type ceramics with cadmium and tungsten dopants

Ceramics of Pb (Zr0.56Ti0.44)O3 with 2.0 at% cadmium and 2.0 at% tungsten dopants (PZT-CW) were created using hot-pressing method. Next, the basic properties of PZT-CW ceramics were investigated. An analysis of the crystallographic structure, tests of dielectric and piezoelectric parameters of the ceramics, as well as internal friction measurements were performed. The PZT-CW ceramics obtained using the hot-pressing method have the microstructure of regularly crystallized grain. For this reason, it holds a set of electrophysical parameters illustrating the possibilities of its application in electrical engineering.

Low frequency elastic and anelastic properties of Pb(Fe0.5Nb0.5)O3 ferroelectric ceramics

Abstract.Pb(Fe0.5Nb0.5)O3 is one of the well studied ferroelectric compound. However, different physical properties of this ceramics were investigated in details, mainly at temperatures in the vicinity of the Curie point, whereas many questions remain about the behavior of physical properties in a wide temperature range, the presence of other phase transitions, types of lattice defects and their effect on macroscopic characteristics, etc. The papers devoted to low frequency elastic and anelastic properties of Pb(Fe0.5Nb0.5)O3 are practically non-existant. Nevertheless, the study of internal friction could give valuable information about different kinds (point, linear and plane) of lattice defects and the changes in the properties of the different phases of investigating ceramics which are related with the several mechanisms measured by the mechanical resonance spectrometer [3]. It is difficult to obtain such results by any other method; moreover sometimes it is impossible at all. In the work, we present results of the measurements of low frequency internal friction Q-1, Youngs modulus E, electric permittivity ε and dielectric loss of angle tgδ in the polycrystalline Pb(Fe0.5Nb0.5)O3 ceramic samples in order to understand a nature of lattice defect interactions and mechanism Q-1 at the phase transition in the Curie and Neel points.

Ferroelectric Properties and Internal Friction in Doped PZT Ceramics

Multicomponent PZT-type solid solution with composition: Pb0.975Ba0.01Ca0.01Sr0.005 (Zr0.52Ti0.48)O3+1.4wt.%Bi2O3+0.3wt.%GeO obtained by hot uniaxial pressing method is described in this paper. There are presented the results of studies of structural, dielectric and internal friction of obtained multicomponent PZT-type ceramics. It has been stated that the dielectric anomalies and internal friction anomalies are observed in similar temperature ranges. Obtained PZT-type ceramics have high value of the dielectric permittivity and low dielectric losses. The high temperature of phase transition and high value of electric permittivity allow considering this material as a base for low frequency and high temperature electromechanical transducers.