Dielectric, Ferroelectric and Strain Properties of (Bi0.5Na0.5)(0.935)Ba0.065Ti1-x(Al0.5Nb0.5)(x)O-3 Lead-free Piezoelectric Ceramics

摘要

Piezoelectric ceramics (Bi0.5Na0.5)(0.935)Ba0.065Ti1-x(Al0.5Nb0.5)(x)O-3 (BNBT-AN) have been synthesized for x = 0, 0.010, 0.015, 0.020, 0.025, and 0.030 through simple solid state reaction technique. Synthesis and sintering of all the systems were successful as single phase was obtained through out. This work explains the influence of AN on morphology, phase structure, electrical and electromechanical characteristics of the parent BNBT matrix. All compositions were single phase perovskites by X-ray diffraction (XRD), that could be confirmed as the tetragonal, P4/m, and rhombohedral, R3c, mixed structures. Tetragonality was increased with increase in the AN content. With similar modification, dynamic piezoelectric constant d*(33)(= S-max/E-max) was increased monotonically gaining a highest value of 354 pm/V corresponding to x = 0.030. The overall increase was found in remnant polarization (P-r) for all the systems except for the one with x = 0.030. Maximum P-r, 30.6 mu C/cm(2), was noted for x = 0.025. This phenomenon was also accompanied by a persistent decrease in coercive field E-c, from 28.0 kV/cm for undoped to 14.5 kV/cm for 3 mol%. The ceramics were signified with encouraging electrical properties.