Lead zirconate titanate ceramics Pb(Zr_1–x Ti _x )O₃ with spatially graded composition from X = 46 to 49 were studied by Raman scanning microscopy and the results were compared with Raman spectra in PZT ceramics of different compositions around the morphotropic phase boundary (MPB). An E-symmetry mode located near 200 cm⁻¹ was found to be a measure of the tetragonality of PZT in both standard graded ceramics. The singular value decomposition method was applied to decompose the experimental spectra of the graded ceramics. Two main contributions were found: one is related to the intensity of the main transverse modes – especially the E(TO2) mode – and it gives evidence of the change between tetragonal and rhombohedral symmetries in the sample; the second one shows changes just through the spatial MPB and it is related to the intensities of A₁(TO2) and E(LO2) modes. All the phonons involved in the main changes correspond to Zr and Ti vibrations.

Piezoelectric composites with 3-3 connectivity gathered attraction due to their potential application as an acoustic transducer in medical imaging, non-destructive testing, etc. In this contribution, piezoelectric composites were fabricated with a material extrusion-based additive manufacturing process (MEX), also well-known under the names fused deposition modeling (FDM), fused filament fabrication (FFF) or fused deposition ceramics (FDC). Thermoplastic filaments were used to achieve open and offset printed piezoelectric scaffold structures. Both scaffold structures were printed, debinded and sintered successfully using commercial PZT and BaTiO₃ powder. For the first time, it could be demonstrated, that using the MEX processing method, closed pore ferroelectric structure can be achieved without pore-former additive. After ceramic processing, the PZT scaffold structures were impregnated with epoxy resin to convert them into composites with 3-3 connectivity. A series of composites with varying ceramic content were achieved by changing the infill parameter during the 3D printing process systematically, and their electromechanical properties were investigated using the electromechanical aix PES device. Also, the Figure of merit (FOM) of these composites was calculated to assess the potential of this material as a candidate for transducer applications. A maximum for the FOM at 25 vol.% of PZT could be observed in this study.