3D printing of doped barium-titanate using robocasting-Toward new generation lead-free piezoceramic transducers

Lead-free piezoelectric ceramics, most commonly prepared via conventional process based on a solid-state synthesis, can be used as acoustical transducers or sensors in many application fields. Particularly in some ap-plications where specific geometries are desirable, the need of complex, time consuming, and costly operations could make conventional process inappropriate. This paper proposes an alternative solution based on additive manufacturing (AM), which is of great interest to control and shape the structure in an automatic manner. A formulation of ceramic slurry, consisting of 80%wt doped barium titanate (BT) and organic mixture, was investigated. The synthesized slurry is revealed to be compatible with the robocasting technique while main-taining good mechanical strength after debinding and sintering steps. Empirical measures together with microscopic analysis confirm high densities of the printed BT ceramics (similar to 95% after sintering), which is consistent to those obtained in literatures. To better assess the material and process performances, microstruc-tural, dielectric and piezoelectric characterizations are conducted on both 3D printed and conventional BT ce-ramics. The results demonstrate that the printed samples give rise to excellent dielectric and piezoelectric properties (d33 coefficient of 260 pC/N and dielectric constant of 1800), which are very close to the values obtained by conventional method on the same composition. As only a few and recent works have been found in the literatures on such systems, this study highlights the considerable and growing potential of robocasting techniques in the field of piezoelectric ceramics. The obtained d33 coefficient is revealed as the highest value reported for printed BT doped systems.