New aspect-ratio effect in three-component composites for piezoelectric sensor, hydrophone and energy-harvesting applications

In this paper the influence of the aspect ratio of ferroelectric ceramic inclusions on the piezoelectric performance and hydrostatic parameters of novel three-component 1-3-type composites based on relaxor-ferroelectric single crystals is studied. Differences in the microgeometry of the ceramic/polymer matrix with 0-3 connectivity and the presence of two piezo-active components with contrasting piezoelectric and mechanical properties lead to a considerable dependence of the piezoelectric performance, hydrostatic response and related parameters of the 1-0-3 composite on the aspect ratio and volume fraction of the aligned ceramic inclusions. The influence of the elastic anisotropy of the ceramic/polymer matrix on composite properties with changes in the aspect ratio and volume fraction of the inclusions is discussed. The piezoelectric performance of the 1-0-3 0.67Pb(Mg_1/3Nb_2/3)O₃-0.33PbTiO₃ single crystal/modified PbTiO₃ ceramic/polymer composite suggests that such a material is of interest for both sensor and energy-harvesting applications due to large values of the piezoelectric coefficient g33∗∼400-550 mV m/N, squared figure of merit d33∗g33∗∼10^-10 Pa^-1 and related anisotropy factor d33∗g33∗/(d31∗g31∗)∼8-9. Such composites can also be used in hydrophone applications due to their large hydrostatic parameters, e.g., dh∗∼10² pC/N, gh∗∼100-160 mV m/N and dh∗gh∗∼10^-11 Pa^-1.