Fabrication and characterization of large area 1–3 piezo-composites based on PMN-PT single crystals for transducer applications

1-3 piezo-composites were fabricated by << dice and fill >> method (DFM) and on a lamination technique (LMT), well adapted to produce large area samples. Two piezoelectric materials (PMN-PT ceramic and single crystal) and epoxy resin have been considered. Design of these composites was performed with finite element analysis (ATILA). Particular attention was paid to sample characterization. An original technique of electrical impedance fitting with FEA was used to determine the properties of both components in their operating conditions. The measured thickness coupling factors of the composites obtained by both methods are between 60 and 80% according to the chosen constituents. Several single element transducers with a center frequency around 1 MHz were fabricated. Their characteristics were compared and results showed that sensitivity of the 1-3 LMT piezo-composite based transducer was slightly lower than that of the DFM one, but sufficient to find applications where large area apertures are required. Moreover, the LMT leaded to a non perfect alignment of the piezoelectric rods in the composites and this effect was quantified by FEA in terms of electromechanical performance.