Elastic Losses and Dispersion in a Dense and Porous Ferroelectrically “Hard” Piezoceramics

Abstract— The paper presents results from a comparative study of elastic losses and dispersion in dense and porous ferroelectrically “hard” piezoceramics of the same chemical composition based on the lead zirconate titanate (PZT) system. To determine complex elastic moduli and their frequency dependences, a technique of the spectral analysis of piezoresonance characteristics has been used including the fundamental and higher-order resonances of the thickness oscillations of disk-shaped samples. The piezoceramic samples of dense and porous piezoceramics have been fabricated using a conventional technique of synthesis and sintering, and a porous structure has been formed using a modified technique of burning-out a pore former. In the porous materials, the regions of anomalous elastic dispersion have been revealed caused by a change in the ratio between the wavelength of resonance oscillations and the characteristic size of heterogeneities of the porous microstructure by increasing the frequency.