An ultrasonic therapeutic transducers using lead-free Na0.5K0.5NbO3–CuNb2O6 ceramics

In this work, we reports on the CuNb2O6 (CN) modified lead-free Na0.5K0.5NbO3 (NKN) based piezoelectric ceramics were synthesized by solid-state reaction methods and sintered at 1075 °C for 3 h. A secondary phase of K4CuNb8O23 was found in the XRD pattern of NKN-based ceramics as the CN dopants is 1 mol%. Microstructural analyses of un-doped and CN-doped ceramics were performed in a scanning electron microscope. The influence of CN content on the microstructure, electrical properties, temperature stability, and mechanical properties of the synthesized ceramics was investigated. The results show that the synthesized ceramics with CN-doped not only had improved density but also exhibited superior piezoelectric characteristics, temperature stability of resonance frequency (TCF), and a better elastic stiffness coefficient than those of pure NKN piezoelectric ceramics. The bulk density (4.47 g/cm3), kp (40%), kt (45%), Qm (1642), C33D (19.64 × 1010 N/m2), TCF (−0.011%/°C) and TCC (0.135%/°C) values for NKN-01CN ceramics obtained from experiments show excellent ‘hard’ piezoelectric properties. Furthermore, a lead-free NKN-01CN ultrasonic therapeutic transducer was successfully driven by a self-tuning circuit.

Research highlights▶ In this paper, CN was added to NKN ceramics to decrease the sintering temperature and to improve the density and piezoelectric characteristics. The influence of CuNb2O6 (CN) content on the microstructure, electrical properties, temperature stability, and mechanical properties of the synthesized samples was investigated. Results show that the samples synthesized with CN-doped not only improved the density but also exhibited superior piezoelectric characteristic, temperature stability of resonance frequency (TCF), and elastic stiffness coefficient than those of pure NKN piezoelectric ceramics. ▶ The bulk density (4.47 g/cm3), kp (40%), kt (45%), Qm (1642), C33D (19.64 × 1010 N/m2), TCF (−0.011%/°C) and TCC (0.135%/°C) values for NKN-01CN ceramics obtained from experiments show excellent ‘hard’ piezoelectric properties. Furthermore, a lead-free NKN-01CN ultrasonic therapeutic transducer was successfully driven by a self-tuning circuit.