The article considers one of the problems hindering the use of ceramic piezoelectric materials based on the BiFeO3 - BaTiO3 phases, which is caused by high values of the dielectric loss tangent of these materials. It is assumed that this is due to different electrical conductivity of individual grains of this type of piezoelectric ceramics (Maxwell-Wagner effects), caused by the presence of iron ions in their composition, which have different oxidation states. In order to equalize the oxidation states of iron ions found in the grains of the considered ceramics, we used annealing of its samples in an atmosphere formed as a result of thermal decomposition of ammonium carbonate. It was found that this technique allows: a) to reduce the values of tgδ of the CPM by 6 - 7 times; b) increase the polarizing field strength by at least 40%, and the value of the longitudinal piezoelectric modulus to 140 pC/N.
Keywords: piezoelectric material, electrical conductivity, dielectric loss, defect, iron ions, Maxwell-Wagner effect, reducing atmosphere, ammonium carbonate
The problem of manufacturing technology heterostructures pezofaza - metal considered in the article. Complexity consists in the fact that during the removal of the polymer in the system at low temperatures are formed porous layers, formed powders separated metal layers, having island macrostructure. One way to solve the problem - reducing the firing temperature heterostructures. Proposed to decrease the sintering temperature by using of functionally active glass-phases. Reducing the sintering temperature of products also allows to replace platinum electrodes inexpensive silver-based alloys. Obtained by solid state reaction method of piezoceramic material has a low sintering temperature (980 ° C) and high electrical parameters. Found that not only the proportion of the vitreous mass, but also their qualitative influence on the properties of piezomaterials
Keywords: heterostructure glass phase, the sintering temperature, porosity, ferroelectric phase
Piezoelectric ceramics on the basis of the phase of (1-x) PbTiO3-xPbZrO3 is the basis of most high-performance piezoelectric materials. Electrophysical and mechanical properties of these materials can vary widely in different ways. Traditional methods include changes in composition within the morphotropic region and doping. Now is the study of the influence of topical makrolegirovaniya the material properties of the PZT system. As a model system was selected phase of the PZT system, the compositions of which MO belong, one of which contains a dopant in the sublattice (A) and another - in the sublattice dopants (B). The studies established that one of the effective ways of varying the parameters piezomaterials may be the formation of solid solutions on the basis of two or more piezoelectric phases having different combinations of electrical parameters
Keywords: Piezoelectric ceramics, doping, kombinorovanie, pezofaza, piezo
Laboratory technology was developed to fabricate flexible piezocomposites with ferroelectric phase - polymers having signal reception factorv • gv 5000 • 10-15 m2 / N. The values of the given coefficient were achieved by switching from a probabilistic (spontaneous) percolation to a correlated one in the process of forming material. This made the production of 0-1–3 piezocomposites, in which a part of piezophase has 0 connectivity, and the other part – 1 connectivity possible. To improve the efficiency of piezocomposite polarization before their manufacturing the surface of piezophase particles, which were obtained by the partial destruction of the porous frameworks, was treated with coupling agent, which did not only improve the polymer adhesion to piezophase, but also allowed the removal of water from the particle surface. The latter effect reduced the value of interfacial conductivity, i.e. prevented the voltage drop of the polarizing field. Matching of polymer conductivity and piezoceramic particles by determining the optimal polarization temperature was carried out as well.
Keywords: piezocomposites, percolation, connectivity, electrophysical properties
It was investigated the influence several additives and process parameters on the properties of piezoelectric ceramics based on PZT phase systems. It was shown that the use of the substitution of Pb2+ ions on the Bi3+, and Ti4+ ions, and Zr4+ to Fe3+ and Mn4+, as well as the method of "chemical assembly «allows to obtain increase the Curie temperature of ceramic samples of 50 - 170°C. The theoretical aspects of this area of research have been discussed in this article.
Keywords: ferroelectric phase, Curie temperature, ceramics, precursors, perovskite, a solid-state method, a method of «chemical assemblage
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