Effects of One‐Dimensional Pressure on the Properties of Several Transducer Ceramics

The effects of one‐dimensional pressure parallel to the polar axis of piezoelectric ceramics have been investigated for a cobalt‐modified barium titanate, NRE‐4, two strontium‐modified lead zirconate titanates, AM‐97 and PZT‐4, and a niobium‐modified lead zirconate titanate, PZT‐5. Pressures up to 10 000 psi had little permanent effect on the polarization and coupling factors of AM‐97 and PZT‐4 but permanently reduced those of NRE‐4 and PZT‐5. The low‐field permittivity decreased initially and then increased with increasing pressure for all materials. At fields up to 3 kV/cm on AM‐97 and PZT‐4, the permittivity and dielectric loss increased severely with pressures to 10 000 psi; the field dependence decreased to approximately constant values independent of the magnitude of the pressure after several hundred hours. Similar measurements on NRE‐4 showed that the changes with pressure and time were not so severe. Changes in the high‐field permittivity and loss due to hydrostatic pressure superimposed on a one...