Experimental measurement of stress at a four-domain junction in lead zirconate titanate

A junction between two lamellar bands of ferroelectric domains in a
lead zirconate titanate ceramic is analyzed using Kikuchi diffraction
patterns in the transmission electron microscope. Indexing of the
diffraction patterns allowed the determination of the three-dimensional
relative orientation of the four different domains at the junction and
thus the characterization of the domain boundaries. The local c/a ratio
could also be determined from the misorientations at the domain
boundaries. Analysis of the data showed that large stresses were
concentrated at the junction, and that this is inevitable at such band
junctions. Such stress concentrations could act as nuclei for cracking
of the ceramic under additional loading in service, perhaps
particularly as a consequence of extended electromechanical cycling.
Moreover, the stresses would increase with increasing c/a, making the
issues all the more serious for Ti-rich compositions having larger c/a
ratios.