The influence of Pb vacancies on the properties of PZT-type ceramic transducers

This article is dedicated to prof. J. Ranachowski The
result of investigations of the influence of lead vacancies on the crystalline
structure of PZT-type ceramic piezoelectric materials is presented. The solid
solution of PbTiO3 - PbZrO3 - [ampersand]Sigma;n=13Pb(B'1-[ampersand]alpha;B''[ampersand]alpha;)O3,
characterized by the perovskite-type structure (ABO3), is the basis of those
materials. The lead vacancies (VPb) was originated by a thermal treatment.
Investigations of the influence of the lead deficiency on the crystalline
structure of PZT-type ceramics have been performed for solid solutions
characterized by compositions corresponding to the tetragonal or rhombohedral
boundary of the morphotropic region (PCR-1, PCR-8: Piezoelectric Ceramics of
Rostov) and to tetragonal phase region compositions (ceramics of
Pb1-x(Zr0.39Ti0.59W0.01Cd0.01) O3). It has been found that the deficiency in
lead causes a reconstruction of the perovskite phase crystalline structure or a
change of the elementary cell parameters of that phase. The solid solutions on
the basis of Pb(Zr,Ti)O3 resolve themselves into PbTiO3, ZrO2 and PbO when the
lead deficiency caused by thermal treatment increases.