ENERGETIC CHARACTERISTICS OF A FERROELECTRIC AS THE WORKING BODY OF A SHOCK-WAVE ENERGY TRANSDUCER

In a previous work it was proposed that the efficiency of ferroelectrics (FE) be estimated by means of the specific energy W equals P**2(2 epsilon //0 epsilon )** minus **1, where P is the residual (spontaneous) polarization of the FE; epsilon and epsilon //0 are the dielectric permittivities of the FE and vacuum. However, if the whole charge P is liberated on the plates of the capacitor containing the FE during loading by a shock wave (SW), then the electrical field being generated in the FE bulk will be maximal E//m//a//x equals P( epsilon //0 epsilon )** minus **1. As is seen from the experimental data, the quantity E//m//a//x exceeds the static electrical strength E**s**t//s//t for all the investigated compositions of the ferroelectric piezoceramics. The expressions derived are discussed in an analysis of the SW energy conversion mechanism and of the singularities of punchthrough development in a shock-compressed FE. Energetic characteristics of a number of ferroelectric-piezoceramics obtained by the method developed by the authors are presented. In contrast to previous work, these characteristics are real, measured in experiments with EET. Consequently, they permit making a confident estimation of the FE efficiency, a single-valued mutual comparison of FE, the selection of one that corresponds maximally to the requirements of the EET being developed.