RESEARCH ON HIGH POWER TRANSDUCER CERAMICS. STRESS SENSITIVITY OF PIEZOELECTRIC CERAMICS: PART ONE: SENSITIVITY TO COMPRESSIVE STRESS PARALLEL TO THE POLAR AXIS.
CLEVITE CORP CLEVELAND OH ELECTRONIC RESEARCH DIV
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Measurements of changes in permittivity, tan delta and D33 as function of compressive stress parallel to the polar axis are presented for lead zirconate-lead titanate transducer ceramics. The hard ceramics PZT-4 and PZT-8 suitable for high power application show large changes of properties for stresses to 20 kpsi, but have good recovery on release of stress. The soft, donor-doped ceramics PZT-5A and PZT-5H suitable for detector applications show serious degradation with successive stress cycles. However, for peak stress below about 10 kpsi their variation of properties and hysteresis per cycle are less than those of the hard ceramics. Permittivity and tan delta of all these ceramics increase with increase of ac electric field. For the soft ceramics the tan delta increase is great enough to eliminate their consideration for uses where efficiency or cool operation are necessary. High ac electric fields combined with compressive stress reduces these detrimental increases for the soft ceramics and increases them for the hard ceramics. Nevertheless, the hard ceramics remain far superior for high power, high stress uses.
- Electrical and Electronic Equipment
- Ceramics, Refractories and Glass
- Electricity and Magnetism