Direct Ink Writing of Three-Dimensional (K, Na)NbO₃-Based Piezoelectric Ceramics

A kind of piezoelectric ink was prepared with Li, Ta, Sb co-doped (K, Na)NbO₃ (KNN) powders. Piezoelectric scaffolds with diameters at micrometer scale were constructed from this ink by using direct ink writing method. According to the micro-morphology and density test, the samples sintered at 1100 °C for 2 h have formed ceramics completely with a high relative density of 98%. X-ray diffraction (XRD) test shows that the main phase of sintered samples is orthogonal (Na_0.52K_0.4425Li_0.0375)(Nb_0.87Sb_0.07Ta_0.06)O₃. The piezoelectric constant d₃₃ of 280 pC/N, dielectric constant ε of 1775, remanent polarization P_r of 18.8 μC/cm² and coercive field E_c of 8.5 kV/cm prove that the sintered samples exhibit good electrical properties. The direct ink writing method allows one to design and rapidly fabricate piezoelectric structures in complex three-dimensional (3D) shapes without the need for any dies or lithographic masks, which will simplify the process of material preparation and offer new ideas for the design and application of piezoelectric devices.