Piezoelectric properties of (Li, Sb, Ta) modified (Na,K)NbO3 lead-free ceramics

Lead-free alkaline niobate based (Na0.52K0.48-xLix)Nb1-x-ySbxTayO3 piezoceramics have been prepared by the conventional mixed oxide method without using other techniques. An experimental formula for producing a set of ceramics with high piezoelectric properties is obtained while cutting down the Ta content and maintaining a high Curie temperature. The highest piezoelectric constant d(33) is 308 pC/N, with a dielectric loss tan delta of about 2.0% and a Curie temperature of 339 degrees C. The samples also possess outstanding high-field piezoelectric strain effects. The high-field piezoelectric strain coefficient d(33)(*) is as high as 490 pm/V. (Li, Sb, Ta) modified (Na,K)NbO3 shifts the orthorhombic to tetragonal phase transition to near room temperature, which plays an important role in the improvement of the piezoelectric properties. (c) 2007 American Institute of Physics.