PIEZOELECTRIC CERAMIC MATERIALS, BASED ON LEAD-ZIRCONATE-TITANATE (PZT), COMPRISING VALENCE-COMPENSATED COMPLEXES CONTAINING AG

摘要

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 (> 800 DEG 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, Ag<+> ions 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.