Low-lead-content piezoelectric ceramics based on (Bi/sub 1/2/Na/sub 1/2/)TiO/sub 3/-NaNbO/sub 3/-PbTiO/sub 3/

Abstract

Dielectric, ferroelectric and piezoelectric properties of a bismuth sodium titanate, (Bi/sub 1/2/Na/sub 1/2/)TiO/sub 3/ [BNT]-based three component solid solution, a/spl middot/(Bi/sub 1/2/Na/sub 1/2/)TiO/sub 3/-b/spl middot/NaNbO/sub 3/-c/spl middot/PbTiO/sub 3/ [BNTP(100a/100b/100c)] are studied from the viewpoint of non-lead-based piezoelectric ceramics. The Curie temperature is around 300/spl deg/C at the optimum composition for piezoelectric properties. D-E hysteresis loops of the BNTP near BNT side show a relatively large remanent polarization, P/sub r/, of about 20-30 /spl mu/C/cm/sup 2/ and a high coercive field of about 50 kV/cm. The maximum electromechanical coupling factor, k/sub t/ in the thickness mode was 0.53 at a=0.84, b=0.03 and c=0.13. BNTP ceramics seem to be efficacious for low lead-content piezoelectric ceramics for environmental protections.