Micro-stereolithography of KNN-based lead-free piezoceramics

The additive manufacturing technique of micro-stereolithography (mu SL) 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 (epsilon(r) = 2150, d(33) = 170 pC/N, P-r = 12.1 mu C/cm(2), E-C = 6.1 kV/cm, and TC = 230 degrees C), which are comparable to those of KNN piezoceramics made by traditional methods. These results suggest that the mu SL technique may serve as an alternative method to manufacture KNN lead-free piezoceramic components, especially for the application with complex architectures.