Effects of BaTiO3 additive on densification mechanism of silver–palladium paste

The investigation of the densification mechanism of BaTiO3-modified 70Ag–30Pd electrode paste was carried out in order to successfully cofire multilayer ceramic devices with Ag–Pd inner electrodes. The addition of BaTiO3 powder made the sintering of 70Ag–30Pd alloy paste clearly change from a partial viscous flow sintering to a nearly complete solid-state-diffusion sintering. The earlier sintering shrinkage caused by the viscous flow of glass frit was retarded distinctly because of skeletal roles of BaTiO3 particles so that the cofiring mismatch between the 70Ag–30Pd paste and the ceramic dielectric was reduced to a tolerable level. The related mechanism and microstructural formation were discussed.