The piezoelectric and dielectric properties of sodium-potassium niobate ceramics with new multiphase boundary

KNN based lead free piezo-ceramics with new additive (Bi0.45La0.05K0.5)ZrO3 (BLKZ) doping have been prepared by conventional solid-state sintering method. The effect of BLKZ content on phase structure evolution was investigated through the X-ray diffraction and the Rietveld refinement method. Both the XRD and Rietveld refinement confirmed a coexistence of rhombohedral-orthorhombic-tetragonal (R-O-T) multiphase in the BLKZ adding KNN systems. The study of the BLKZ content on the phase transition temperature of the ceramics manifested that the BLKZ could modify the phase transition temperature of rhombohedral-orthorhombic (T (R-O)) and orthorhombic-tetragonal (T (O-T)) to room temperature simultaneously, thus, a new R-O-T multiphase coexistence boundary would be constructed in the KNN systems. A piezoelectric coefficient of d (33) similar to 385 pC/N with a T (c) of 245 A degrees C were observed in the KNN ceramics when the BLKZ content is 3.5 mol%.