ELECTROELASTIC PROPERTIES OF POROUS PIEZOELECTRIC CERAMICS OBTAINED BY TAPE CASTING

The electro-elastic properties of porous piezoelectric ceramics obtain ed by tape casting have been investigated and related with sample micr ostructure. The samples obtained by tape casting show very narrow pore size distribution for all porosities up to 60%. Reproducible properti es and regular dependence of electro-elastic constants on porosity are consequently obtained. It was found that some material properties are improved with respect to dense PZT; in particular, the piezoelectric voltage constant g(h) and the figure of merit d(h)g(h) increased, whil e the acoustical impedance decreased by one order of magnitude. These properties make the material very attractive for applications where go od sensitivity and good matching with the medium are required. For com parison a different set of samples have been prepared by mixing the sa me PZT powder with 40-50% methylethylcellulose powder. Preliminary sin tering studies on pure PZT powder have been also presented.