time stability of mechanical and dielectric parameters in the pzt type ...

308 Zachariasz R., Czerwiec M., Ilczuk J.
generators, delay-line transducers, wave filters, piezoelectric micromotors, microrobots,
actuators, etc. [1-6].
In the figure 1, the dependences of the basic parameters of PZT ceramics as a function of
concentration of PbTiO 3 are presented [7]. We can observe seven characteristic areas for PZT
ceramics:
I – materials used in high frequency transducers with low value of the dielectric permittivity ε
(200÷500) and high value of the electromechanical coupling coefficient k p ,
II – transducers with high sensitivity and high value of the g ij modulus, used in accelerators,
defectoscopes, devices of medical diagnostics and memory – devices,
III – low frequency transducers with high value of the dielectric permittivity ε and
electromechanical coupling coefficient k p as well as high values of the tangent of dielectric loss
angle tgδ,
IV and V – ferroelectric hard materials with high resistance on the electrical and mechanical
influences, materials used in electroacoustic transducers, piezotransformers, piezomotors,
VI – materials with high value of the stability of the resonance frequency used in filters and
selective devices,
VII – high-temperature transducers with high values of the Curie temperature above 693 K.
This materials are used in transducers, whose working temperature carries out about 590 K.
∆ f r / f r
(213-358K)
Re
MR
(Re+T)
T
2 σ
k ij Q
m
σ
Q m
Q m
γ
g ij
k ij
d ij
σ
ε / ε 33 0
I
II
III
IV
V
VI
VII
PbTiO
3
Fig. 1. The dependences of the basic parameters of PZT ceramics as a function
of concentration of PbTiO 3 [7]