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This paper presents a stepped horn transducer based on lead-free piezoelectric ceramics. A two-step titanium horn has been bonded to a Ba0.95Ti0.95Sr0.05Zr0.05O3 (BSZT) lead-free piezoelectric ceramic disk. The stepped horn is a promising candidate for transducer design mainly due to its efficacious mechanical amplification. The strontium and zirconium doped barium titanate has been prepared in disk-shape and poled in a thickness direction. When an AC voltage is applied to the electrodes of the driving disk, the lead-free piezoceramic disk produces radial ultrasonic contractions and expansions. The stepped horn transforms and amplifies the radial deformation into an axial vibration of the horn tip. At resonance, the deformation of the horn is significantly enhanced, the axial displacement of the horn tip has been measured near the resonance frequency and compared to that produced by a PZT driven transducer. Finite element modeling has been conducted to determine the vibration mode and resonance frequency of the device. [ABSTRACT FROM AUTHOR]

Lead-free piezoelectric ceramic 0.90(Bi1/2Na1/2)TiO3–0.05(Bi1/2K1/2)TiO3–0.05BaTiO3 (BNKBT-5) rings (OD=12.7 mm, ID=5.1 mm and 2.3-mm thick) were fabricated and characterized. Four ceramic rings were used as the driving element in an ultrasonic wirebonding transducer and the performance of the transducer was characterized. The lead-free transducer was found to have comparable voltage rise and fall times as a lead-based PZT transducer and has a relatively large vibration amplitude, thus showing that BNKBT-5 has the potential to be used in fabricating lead-free ultrasonic wirebonding transducers. [ABSTRACT FROM AUTHOR]

Lead-free piezoelectric 0.75(Bi 1/2 Na 1/2 )TiO 3 -0.20(Bi 1/2 K 1/2 )TiO 3 -0.05BaTiO 3 ceramics(abbreviated as BNKBT-20) with addition of 0.2, 0.4, 0.6 and 0.8 wt% of CeO 2 , respectively, were prepared by a conventional mixed oxide method. The addition of CeO 2 can reduce the dissipation factor and enhance the mechanical quality factor significantly. The composition with 0.4 wt% CeO 2 has a piezoelectric d 33 constant of 129 × 10 - 12 C/N and a relatively low dissipation factor (tan δ = 1.8%) at 1 kHz which shows a 50% reduction in the dissipation factor when compared with BNKBT-20 before doping (tan δ = 3.74%). [ABSTRACT FROM AUTHOR]