Lead-free piezoceramic materials for SONAR transducers

Piezoelectric materials are widely used in electrotechnology to convert between electrical and mechanical energy in sensors and actuators. An important field of application is acoustics (e.g. medical ultrasound imaging), in which the piezoelectric material converts electrical signals to acoustic waves and vice-versa. The market leading material for these applications is lead zirconate titanate ceramic, known as PZT. Due to the worldwide legislation limiting the use of lead in electronics, there is a possibility that PZT may become obsolete and be replaced with lead-free materials. Hence the aim of this project is to identify and optimise a lead-free piezoelectric ceramic specifically for use in sonar devices. The project has the following objectives:

1. In collaboration with the industrial sponsor, prepare a target specification for lead-free piezoelectric materials in sonar devices.
2. Survey the literature to compare the properties of the leading candidate lead-free piezoelectric materials.
3. Prepare and test examples of the leading candidate materials.
4. Select a material for further development based on its potential to meet the target specification.
5. Carry out a material optimization programme by varying composition, adjustment of defect chemistry via doping, and variation of process variables.

The project will employ the latest ceramic process techniques and a wide range of dielectric, ferroelectric and piezoelectric characterization techniques with which to study the relationship between the composition, processing and properties of the materials