Piezoelectric properties of [001]-textured (K, Na)(Nb, Sb)O3-CaZrO3-(Ag, Bi)ZrO3 ceramics and their application in panel loudspeakers

A [001]-textured 0.96(K0.5Na0.5)(Nb0.93Sb0.07)O3-0.02CaZrO3-0.02(Ag0.5Bi0.5)ZrO3 [KNNS-0.02CZ-0.02ABZ] piezoceramic exhibited a large d33 of 760 pC/N, which is close to the largest d33 reported in literature. The large d33 of this sample can be explained by the existence of nanodomains and the tetragonal-orthorhombic-rhombohedral (T-O-R) structure, with a large portion of the O-R structure. Piezoelectric loudspeakers were produced using [001]-textured KNNS-(0.04 – x)CZ-xABZ piezoceramics (0.0 ≤ x ≤ 0.04). The loudspeaker with an actuator fabricated using the [001]-textured KNNS-0.02CZ-0.02ABZ piezoceramic exhibited the largest sound pressure level (SPL) owing to its large d33. The average SPL of the loudspeaker was 68.5 dB at a distance of 30 cm in the audible frequency range with an input of 6 Vrms. The loudspeaker produced using the bimorph-type actuator with the KNNS-0.02CZ-0.02ABZ piezoceramic exhibited an improved average SPL of 75.6 dB. Therefore, the [001]-textured KNNS-0.02CZ-0.02ABZ piezoceramic is an excellent material for loudspeakers.