Micro-stereolithography of KNN-based lead-free piezoceramics

The additive manufacturing technique of micro-stereolithography (µSL) is applied to fabricate alkaline niobate (K0.48Na0.52NbO3, KNN) based lead-free piezoceramics. Complex KNN-based piezoceramic green parts with fine dimensional characteristics, such as a piezoceramic transducer array and a hollow hemisphere, have been printed. The two-step debinding and sintering processes are employed to obtain crack-free dense KNN ceramics with complex shapes. These printed KNN ceramics exhibit superior piezoelectric and ferroelectric performance (er = 2150, d33 = 170 pC/N, Pr = 12.1 μC/cm2, EC = 6.1 kV/cm, and TC = 230 °C), which are comparable to those of KNN piezoceramics made by traditional methods. These results suggest that the µSL technique may serve as an alternative method to manufacture KNN lead-free piezoceramic components, especially for the application with complex architectures.