Some of important conclusions of my work are:
* A unique AE experiment can be performed to detect structural phase
transition (cubic to tetragonal) in PZT ceramics.
* AE signals obtained from PZT ceramics during the application of a dc
field below but near Tc, were used to discriminate between two
different source mechanisms - namely the piezoelectric strain at lower
fields and strain due to domain alignments at higher fields.
* AE can be used to study the improper annealing or debonding of the
counter electrode in PZT ceramics.
* Domain pinning is a major source of fatigue in soft PZT ceramics and
at higher fatigue domain switching and microcracking facilitate each
other.
* I found that microcracks initiate with greater ease at higher fatigue levels
in unpoled PZT samples when compared to the poled ones.
* In the case of hard PZT ceramics, AE results point to an interaction
between domains and defect dipoles.
* Complex impedance spectroscopy studies on fatigued PZT samples
revealed that major conduction mechanism does not change with
fatigue in these ceramics.
* Simulation studies on waveguides revealed that discrimination of
different source mechanisms of AE is possible using pattern
recognition analysis even when the signals are being received through
a waveguide.
For a copy of my synopsis please write to me at: [email protected]