Piezoelectric Properties of (1-x)(Na0.5K0.5) NbO3-xLiTaO3 Lead-free Piezoelectric Ceramics

Density (1-x)(Na
_0.5
K
_0.5
)NbO
_3-x
LiTaO
₃
(NKN-LT) lead-free piezoelectric ceramics have been synthesized by conventional mixing oxide process. A morpho-tropic phase boundary(MPB) between orthorhombic phase and tetragonal phase had been found in NKN-LT system. It was found that the piezoelectric properties of NKN-LT ceramics, at x = 0.065 near MPB, is about d
₃₃
= 225 pC/N and the planar electromechanic coupling coefficient k
_p
= 0.32-0.38. The effect of LiTaO
₃
(LT) doped on the piezoelectric properties of (Na
_0.5
Ko
_0.5
)NbO
₃
(NKN) ceramics was also discussed.