Effective oriented direction for enhancement of the piezoelectric properties of crystal-oriented (Li, Na, K) NbO3 ceramics

Abstract

ABSTRACT Crystal-oriented (Li, Na, K) NbO3 ceramics (LNKN) were prepared by colloidal processing under a strong magnetic field, sintering, and subsequent electrical poling. The [001] direction of the LNKN particles with a tetragonal phase was oriented parallel to the magnetic field. By changing the direction of the magnetic field and machining, [001]-, [100]- and [110]-, and [101]-oriented LNKN powder compacts were formed. After phase transition during sintering, the crystal reorientation was furthermore enhanced by domain switching under an electric field. The obtained [001]-, [001]- and [101]-, and [101]-oriented LNKN ceramics showed piezoelectric constants d31 and d33 of 65 and 120 pm/V, 96 and 165 pm/V, 108 and 180 pm/V, respectively. In addition, d31 and d33 increased in the order of the [001]-, [001]- and [101]-, and [101]- oriented LNKN ceramics, indicating that the [101] orientation caused by domain switching is more effective for enhancing the piezoelectric properties compared to crystal orientation to the c-axis direction.