A stepped horn transducer driven by lead-free piezoelectric ceramics

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 hom 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 hom 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.