Microstructure and Electrical Properties of Porous PZT Ceramics Fabricated by Different Methods

Abstract

Porous PZT ceramics were prepared by two approaches: burnable plastic spheres (BURPS) process with varied percentages (2.5, 5.0, 7.5, 10.0, and 12.5 wt%) of stearic acid as the pore‐forming agent and tert‐butyl alcohol‐based gel casting with different initial solid loadings (10, 15, 20, and 25 vol%). The resultant samples were characterized to evaluate effects of different preparation techniques on the microstructure and electrical properties of porous PZT ceramics. Two batches of samples possessed different pore size and morphology. Dielectric and piezoelectric properties basically showed a descending trend with increasing porosity and the results agreed with the theoretical prediction. Relative permittivity possessed different values even at the same level of porosity due to the difference in pore size and pore morphology. Piezoelectric constant d33 was generally larger for samples by gel casting than for those by the BURPS process mainly induced by the variety in the preparation processes. However, the acoustic impedance exhibited a linear decrease with an increasing porosity regardless of different pore size or morphology introduced by different preparation techniques.