Phase Structure and Electrical Properties of Lead-Free (K0.5 Na0.5)NbO3-YMnO3 Ceramics

Lead-free piezoelectric ceramics (1-x) (K0.5Na0.5)NbO3-xYMnO(3) (KNNYM) have been fabricated by using conventional sintering technique. The structure, dielectric and piezoelectric properties of the KNNYM ceramics were investigated. It was found that the ceramics possess orthorhombic structure at room temperature, and have high Curie temperature (T-C > 400 degrees C). The increase of YMnO3 (0 < x <= 0.06) additives is very effective in improving the mechanical quality factors (Q(m)) of the ceramics, and the temperature of the orthorhombic to tetragonal phase transition (TO-T) also increases, however, a secondary phase could be found in the ceramics when x > 0.02.