Ceramics-Silikáty 31, (4) 289 - 298 (1987) |
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THE EFFECT OF GRAIN SIZE ON THE PROPERTIES OF PIEZOCERAMICS IN THE SYSTEM PbMg1/3Nb2/3O₃-PbTiO₃-PbZrO₃ |
Nejezchleb Karel 1, Kroupa František 2 |
1 Research Institute of Electrotechnical Ceramics, Pospíšilova 281, 500 64 Hradec Králové
2 Institute of Plasma Physics, Czechoslovak Academy of Sciences, Pod vodárenskou věží 4, 182 11 Prague 8 - Libeň
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Internal stresses arise during poling of piezoelectric transducers as a result of reorientation of the domain structure. If the grain size exceeds a certain critical limit, the internal stresses cause cracking at the grain boundaries. An expression for the critical grain size is derived in the
present study. The formation of cracks by poling is determined in coarse-grained ceramics Pb(Mg1/3Nb2/3)0.44Ti0.44Zr0.12O₃, doped with 1 wt. % MnO₂. The presence of cracks is revealed by impaired mechanical strength and increased internal friction of the piezoelectric transducers. |
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