Interfacial reaction of Ag/Pd metals with Pb-based relaxor ferroelectrics including additives

In order to effectively control the interfacial reactions during co-firing a multilayer ceramic device (MLCD), different effects of silver/palladium on Pb-based relaxor ferroelectric ceramics were investigated by means of a series of powder X-ray diffraction (XRD) spectra and chemical reaction thermodynamics. It is found that the reaction kinetics of palladium and Pb-based relaxor ceramics lies in the activity of palladium and the structural stability of relaxor ferroelectric ceramics. In this respect, silver can decrease the activity of palladium so that a less serious interfacial problem exists in a MLCD with 30Pd/70Ag electrodes. Moreover, BaTiO3 and SrTiO3 ceramic additives were found to effectively suppress Pd-PNN reactions because of increasing the structural stability of PNN. It is pointed out that the addition of BaTiO3 or SrTiO3 ceramic powders into the dielectric layers and particularly into the inner electrode pastes may play dual roles, including modifying the densification mismatch and preventing the interfacial reactions between the electrodes and the dielectric layers.