B.6 Multilayer PZT ceramics

Stipendiat: Anna Medesi

 Oxide ceramics, which exhibit the perovskite structure (e. g. PZT) are highly important for electro-mechanical energy conversion applications in  energy harvesting (Project A.4). Currently there are several drawbacks in the manufacturing process of bending mode converters, based on metallized PZT thick films (Fig. 1). On the one hand the metallized PZT layers have to be glued together, which inflicts problems on the connection of the electrodes of each layer. On the other hand the bulky ceramics, which currently are used, limit the minimum thickness and thus the maximum electrical field, which can be application generated.
The aim of this research project is the development of a bending vibrational transducer made of PZT thick-film films (50-200 microns). The material composition should allow the green sheets to be sintered together with the metallization (Au). This will facilitate not only the integration of piezoelectric transducers. It also will improve their performance. Therefore it is essential to reduce the sintering temperature in order to prevent reactions between the ceramic and the metal. The necessary control of microstructure will be ensured by a tailored powder treatment and by an optimized particle size distribution.  The PZT layers will be generated by tape-casting of slurries. Special attention will have to be paid to the rheology of the slurry and the drying stop of the green tapes.

 

Fig. 1: Cross sectional view of a triple-layered piezoceramic stack.
[C. Eichhorn et al., J. Micromech. Microeng. 21 (2011) 104003]