Direct ink writing of 3D piezoelectric ceramics with complex unsupported structures

Piezoelectric ceramic , as a typical smart material, shows great potential in applications of sensing & actuation, smart structure and energy harvesting. However, the use of traditional methods to fabricate complex and high-precision piezoelectric ceramic devices faces huge technical difficulties and high molding costs. Direct ink writing is a typical additive manufacturing technology, but has limited capabilities when preparing ceramic products with complex unsupported structures. In this work, a combined process of direct ink writing (DIW) and secondary shaping of flexible ceramic green body has been developed and proved to produce complex piezoelectric ceramics. The PZT ink shows shear thinning behavior and appropriate viscoelasticity such as moderate viscosity and high storage modulus . The printed green body can be flexibly deformed and the samples after polarization show good piezoelectric properties , with an average d 33 up to 265 pC/N. This work demonstrates an attractive method for geometrically complex piezoceramic with unique macro structure due to its simplicity and low cost, and provides a solution to the key problems in the existing manufacturing technology of 3D ceramics.