Environmentally friendly water-based robocasting of complex barium titanate structures

In this work, barium titanate structures (e.g., cellular and monolithic) were fabricated by robocasting, which is an extrusion-based additive manufacturing process in which shear-thinning pastes are deposited. An environmentally friendly water-based paste was investigated and printed layerwise to achieve the desired structure. After sintering, a relative density of 97 % was obtained, and the mechanical and physical properties of the printed samples were investigated. The flexural strength of ∼40 MPa and the hardness of ∼3 GPa of the fabricated samples are comparable to literature data. Additionally, the piezoelectric coefficient d₃₃ of the structures was measured. With values of around 200 pC/N, both monolithic and cellular samples show good results without the need for further densification. Despite the high porosity of the cellular structures, they show high piezoelectric coefficients, which opens up several new application fields and shows the importance of combining additive manufacturing and piezoelectric ceramics.