(Bi/sub 1/2/Na/sub 1/2/)TiO/sub 3/-PbTiO/sub 3/-BaTiO/sub 3/ solid solution for piezoelectric ceramics

Piezoelectric and ferroelectric properties of a bismuth sodium titanate, (Bi/sub 1/2/Na/sub 1/2/)TiO/sub 3/ (BNT)-based solid solution, (Bi/sub 1/2/Na/sub 1/21-x/) (Pb/sub a/Ba/sub b/)/sub x/ TiO/sub 3/ (a+b=1) (BNTX), were studied from the viewpoint of a new group of lead-free or low-lead-content piezoelectric ceramics with a rhombohedral (F/sub alpha /)-tetragonal (F/sub beta /) morphotropic phase boundary. A rhombohedral (F/sub alpha /)-tetragonal (F/sub beta /) morphotropic phase boundary was shown to exist at x approximately=0.135 in the case of b=0. BNTX ceramics are superior for piezoceramics applications in high-frequency ultrasonic uses, with a lower free permittivity in /sub 33/ /sup T// in /sub 0/, and a high electromechanical coupling factor k/sub t/ or k/sub 33/ along with a high mechanical strength.<
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