Lead-Free Piezoceramic Materials for Ultrasonic Applications

Abstract:
PI Ceramic (PIC) has developed high-performance lead-free ceramic materials according the EU directive to reduce hazardous substances (RoHS2) [1]. PIC 700 is the first lead-free piezoceramic composition commercially available by PI Ceramic GmbH. After extensive testing lead-free ceramic components can be offered on the market of ultrasonic transducers. PIC 700 is based on Bismuth Sodium Titanate (BNT) and has very similar characteristic properties to Barium Titanate materials but with a higher working temperature up to 150deg C. The permittivity and the piezoelectric coupling factors are lower in comparison to conventional Lead Zirconate-Lead Titanate (PZT) compounds. But the strong anisotropic behavior offers suitable conditions for sensor and transducer applications in the MHz range. Ultrasonic transducers with PIC 700 components have been produced and tested in direct comparison with the conventional PZT material PIC 255. Measurement results of the dielectric and electro-mechanical properties of PIC 700 components and transducers will be presented. Furthermore results about the behavior in the application in terms of signal form and level as well as the temperature characteristics will be shown in this study.