High sensitive PZT ceramics and its applications to ultrasonic diagnostic transducers

Abstract

The principle of multiple substitutions in the A-site defined by L. Eyraud et al. (Reference 1) was developed. The authors added BaO, SrO and the third substituting oxide of La203 or Bi203 etc. simultaneously to a PZT composition to obtain higher sensitive piezoceramics (k_p = 0.68, d ₃₃ = 700.10⁻¹² C/N, g₃₃ = 40.10⁻³ V.M/N and ε ^T ₃₃ = 2000) than the materials with only BaO, SrO substituted (Reference 1). A 2.5 MHz ultrasonic Dopier diagnostic transducer made of this material with an acoustic diverging lens was designed (Reference 2). It transmits a wide angle beam and features higher sensitivity and S/N. This kind of transducer has been used in the ultrasonic Doppler fetal and delivery monitor with satisfactory results.