Effect of nano-sized TiO2 powder addition on characteristics of silver-palladium electrodes

This study presents the sintering behavior of silver/palladium electrode powders to which have been added TiO2 nanoparticles, and the effect this additive has on the ability of the electrode to match the characteristics of piezoelectric ceramics, Pb(Zr, Ti)O3. The densification (shrinkage) of the electrodes was investigated as a function of sintering temperature, and the reaction between the ceramic matrix and the electrodes was studied. The densification of the TiO2-enhanced electrode paste during the sintering process was explained with reference to a solid-state diffusion mechanism which integrated the TiO2 into the ceramic. Reactions occurred between the ceramic and electrode layers, resulting in reduced internal stress and enhanced mechanical adhesion. Based on these results, it is clear that high adhesive strength and good electrical conductivity of more than 104/Ω cm can be obtained in multilayer ferroelectric devices composed of stacks of ceramic and electrode layers provided the contain these nanoparticles. In the sintering process, interfacial diffusion of TiO2 occurred and, as a consequence, coarse grains of PZT were formed at the interface.