Textured (K0.5Na0.5)NbO3 ceramics prepared by screen-printing multilayer grain growth technique

The screen-printing multilayer grain growth (MLGG) technique is successfully applied to alkaline niobate lead-free piezoelectric ceramics. Highly textured (K0.5Na0.5)NbO3 (KNN) ceramics with 〈0 0 1〉 orientation (f = 93%) were fabricated by MLGG technique with plate-like NaNbO3 templates. The influence of sintering temperature on grain orientation and microstructure was studied. The textured KNN ceramics showed very high piezoelectric constant d33 = 133 pC/N, and high electromechanical coupling factor kp = 0.54. These properties were superior to those of conventional randomly oriented ceramics, and reach the level of those of textured KNN ceramic prepared by tape-casting technique. Compared with other grain orientation techniques, screen-printing is a simple, inexpensive and effective method to fabricate grain oriented lead-free piezoelectric ceramics.