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

In order to effectively control the interfacial reactions during co-firing a multilayer ceramic device (MLCD), different effects of silver/palladium o n Pb-based relaxer ferroelectric ceramics were investigated by means of a s eries of powder X-ray diffraction (XRD) spectra and chemical reaction therm odynamics. It is found that the reaction kinetics of palladium and Pb-based relaxer ceramics lies in the activity of palladium and the structural stab ility of relaxer ferroelectric ceramics. In this respect, silver can decrea se the activity of palladium so that a less serious interfacial problem exi sts in a MLCD with 30Pd/70Ag electrodes. Moreover, BaTiO3 and SrTiO3 cerami c additives were found to effectively suppress Pd-PNN reactions because of increasing the structural stability of PNN. It is pointed out that the addi tion of BaTiO3 or SrTiO3 ceramic powders into the dielectric layers and par ticularly into the inner electrode pastes may play dual roles, including mo difying the densification mismatch and preventing the interfacial reactions between the electrodes and the dielectric layers. (C) 2001 Elsevier Scienc e Ltd and Techna S.r.l. All rights reserved.