Lead-Free Piezoelectric Ceramics of (Bi_1/2Na_1/2)TiO₃–KNbO₃–1/2(Bi₂O₃·Sc₂O₃) System

Abstract

Bismuth sodium titanate, (Bi 1/2 Na 1/2 )TiO 3 (BNT)-based solid solution, a (Bi 1/2 Na 1/2 )TiO 3 – b KNbO 3 – c 1/2(Bi 2 O 3 ·Sc 2 O 3 ) ( a + b + c =1), [KTNS(100 a /100 b /100 c )], was studied for its dielectric, ferroelectric and piezoelectric properties, as a new group of lead-free piezoelectric ceramics. Electrical measurements such as dielectric and piezoelectric properties show that the KTNS(100 a /100 b /100 c ) ceramics near the BNT side have a relatively high electromechanical coupling factor, k 33 (=0.47). On particular, the amount of modified Bi ions has an effect on k 33 . These ceramics seem to be a candidate for lead-free piezoelectric ceramics.