Piezoelectric and dielectric properties of Lix(K0.46Na0.54)1−xNb0.86Ta0.1Sb0.04O3 lead-free ceramics
(1. College of Materials Science and Engineering, South China University of Technology,Guangzhou 510640, China;2. School of Chemical Science, South China University of Technology, Guangzhou 510640, China)
Abstract: Lead-free piezoelectric ceramics Lix(K0.46Na0.54)1−xNb0.86Ta0.1Sb0.04O3 (with x ranging from 0 to 0.1) were synthesized by conventional solid state sintering method. The effect of cationic substitution of Li for K and Na in the A sites of perovskite lattice on the structure, phase transition behavior and electrical properties were investigated. Morphotropic phase boundaries(MPB) between orthorhombic and tetragonal phase are found in the composition range of 0.06≤x≤0.08. Analogous to Pb(Zr,Ti)O3, the dielectric and piezoelectric properties are enhanced for the composition near the morphotropic phase boundary. The Li0.06(K0.46Na0.54)0.94- Nb0.86Ta0.1Sb0.04O3 ceramics show excellent electrical properties, that is, piezoelectric constant d33=215 pC/N, planar electromechanical coupling factor kp=41%, dielectric constant =1 303, and dielectric loss tan δ=2.45%. The results indicate that Lix(K0.46Na0.54)1−x Nb0.86 Ta0.1Sb0.04O3 ceramic is a promising lead-free piezoelectric material.
Key words: lead-free ceramics; piezoelectric ceramics; piezoelectric property; dielectric property