Tailoring Crystallographic Texture Through Direct Ink Writing of Piezoelectric Ceramics

ABSTRACT Control of crystallographic texture is key to improving the properties of piezoelectric ceramics, but it has so far mainly been realized in the form of fiber textures perpendicular to the dominant surface of simple 2.5D structures. This work demonstrates how grains in piezoelectric ceramics can be aligned in complex patterns and shapes via material extrusion‐based additive manufacturing, specifically direct ink writing. Needle‐shaped K 0.5 Na 0.5 NbO 3 template particles with ⟨100⟩ pseudocubic orientation are used in a K 0.5 Na 0.5 NbO 3 ‐based ink, such that they align during direct ink writing due to shear forces in the nozzle. The templates control grain growth during subsequent sintering, enabling the additively manufactured piezoelectrics with a texture characterized by a Lotgering factor of 83%, which is a significant improvement compared to previous achievements. The piezoelectric response of this textured material is improved by 88%. Furthermore, as the dominant crystallographic orientation follows the nozzle movement, the texture can be controlled in each print line. This work opens new design possibilities for improved ceramics, combining tailored microstructures and complex shapes, and a significant advancement of the direct ink writing technique.