Abstract: Effect of Ag diffusion of Pd-Ag inner electrode on electric properties of multilayer chip ZnO varistor was studied. The results show that Ag contents in inner electrode play a very important role in the electric properties of multilayer chip ZnO varsitor. When the Ag content is less than 90%, the properties are good, but when the Ag content is more than 90%, the properties deteriorate with the increase of the Ag content. And the properties of MLCV having pure Ag inner electrode are the worst. The capacitance reflecting the grain-boundary barrier capacitances decreases with the increase of Ag content. The analyses of V-I characteristic curves and complex impedances indicate that, during the co-firing process of the ceramic and inner electrode, with the increase of Ag content in inner electrode, the velocity of Ag diffusing in the ZnO lattice will speed, and the grain resistance increases excessively, and the electric properties of MLCV deteriorate.

Key words: multilayer chip varistor, low firing, sliver diffusion, grain resistance, electronic properties