SU619470A1 - Piezoelectric ceramic material - Google Patents

Description

(54) PIEZOELECTRIC KERAL CHESKY MATERIAL

The invention relates to the field of piezotechnics and can be used to create electromechanical transducers based on the phenomenon of piezoelectricity, in particular for co-links of medium and low frequency piezoelectric elements. Piezoelectric ceramic materials based on solid lead zirconate titanate jj are known. However, their use in a number of cases, in particular, for creating transducers operating at frequencies above 300 MHz, is difficult because of the relatively low sound velocity and high dielectric constant. In addition, these materials have relatively high density values. The closest technical solution to this is the material based on the solid solution No NbOj-LiNbQj. This material is characterized by a combination of low dielectric constant - “/, high sound velocity Vijj and rather high piezoelectric characteristics. In addition, lower density values make it possible to manufacture products of lower weight. However, for the use of day-time elements of electromechanical transducers, the dielectric constant, JJ, and the piezoelectric module d. the systems are not high enough, the increased dielectric losses characteristic of this material, contributing to the heating of the converter, significantly reduce its efficiency. The aim of the invention is to increase the dielectric constant, piezoelectric mode, w and reduce dielectric losses with low density and high speed of sound. The goal is achieved by the fact that the piezoelectric ceramic material containing the Na NtoOjjLiNbOjH is the third component, as the third component, contains NtaOj in the following ratio nshodash-gx components, mol%:

NaNtO,

76.00-86.5 L-iNtlO,

1.00-9.00, e NtjOj

12.50-15.00

Claims (1)

The synthesis of the compositions is carried out according to the usual ceramic technology by double firing. Thermal synthesis temperatures of 800, 850 ° C, durations of 5 and 5 hours. Sintering is carried out by hot pressing in the following mode; temperature 105 O-I50 C, pressure 200 kg / cm holding time 40 min. This material has the following values (depending on the composition) density:. R. sound speed and mechanical quality factor Q dd p 3.9-4.5 g / cm V5.1-5.9 km / s q250-450. The invention of the piezoelectric ceramic material containing No MbOj .UiNbO, characterized in that, with the increase of the dielectric constant, of the piezoelectric module The polarization of the samples is carried out in a polysipoxane fluid for 45 min in a field of 2.5-3.5 sq / mm with a subsequent cooling, under a field of up to 9 o C. The value of the dielectric constant of the tangent of the dielectric loss angle tff cG of the piezoelectric module 3, and the Curie points Tkr of a number of compositions are given in the table. and reduce dielectric loss at low density and high speed of sound, it additionally contains Cd 0, with the following ratio of components, mole,%: NqNbO 76.00-86.50 L-iNbO 1.00-9.00 C- "3o NbOj 12.50-15.00 Sources of information taken into account during the examination: 1, Smazhevska E. G, and Feldman N. B. Piezoceramic ceramics. Soviet Radio, 1975, p. 45-46.