Ceramtec Ag, Innovative Ceramic Engineering

Ceramtec Ag

Gunter Helke

The invention relates to piezoelectric ceramic materials based on the system Pb(Zr,Ti)O, i.e. solid solutions of lead zirconate PbTO, characterized by having very good dielectric and electromechanical properties that can be adopted for different uses by modifying the composition. The piezoelectric ceramic materials based on the system Pb(Zr,Ti)Oare modified in order to obtain a high level of piezoelectric activity. The invention provides piezoelectric ceramic materials based on lead zirconate titanate (PZT) having the crystal structure of perovskite with formula ABO, which are characterized by a substitution of heterovalent acceptor and donator ions at Zr/Ti sites.

Piezoelectric ceramic materials based on lead zirconate titanate (PZT) having the crystal structure perovskite

The characteristics of piezoceramic multilayer actuators based on lead-zirconate-titanate are determined to a great extent by the compatibility of PZT ceramics having a low sintering temperature with the AgPd internal metallisation during cofiring. It is important to take into consideration that Ag ions in PZT modifications have a high diffusivity at high temperatures (&#x3e;800&#xb0; C.) and in addition act as acceptor doping when integrated into the PZT system. The reduction of the fraction of the precious metal palladium, which prevents diffusion, is limited, as silver increasingly diffuses into the piezoceramic as the silver fraction in the internal electrodes increases. According to the invention, Agions are used to form valence-compensated compositions of the PZT system. A higher level of deformation is maintained, i.e. the acceptor-donor effect in the system is very similar to that of the PZT system modified conventionally without internal electrodes.

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Munich, Georgia

Gunter Helke