Effects of Silver Doping on the Reliability of (Pb0.875 Ba0.125)[(Mg1/3 Nb2/3) 0. 5(Zn1/3 Nb2/3)0.3 Ti0.2] O3 Relaxor Dielectric Ceramics

Abstract

The reliability of the silver‐doped dielectric ceramic (Pb0.875Ba0.25)0.995[(Mg1/3Nb2/3)0.5(Zn1/3Nb2/3)0.3Ti0.2]O3 was investigated to speculate on the effects of silver diffusion from internal electrodes into dielectric layers on the reliability of multilayer ceramic capacitors (MLCs). The addition of silver into the dielectric ceramic degraded the insulation resistance under humid loading conditions. Scanning transmission electron microscopy (STEM) revealed that a Pb‐rich grain boundary phase exists at triple points of Ag‐doped specimens. The Pb‐rich phase appeared to be PbO by X‐ray photoelectron spectroscopy (XPS). Degradation of insulation resistance was interpreted as a result of silver migration from the anode to the cathode through a grain boundary phase dissolved in water. Although silver diffusion from internal electrode layers in MLCs into dielectric layers was confirmed by STEM, a secondary phase was not observed. Intensive study is needed to clarify the effect of silver diffusion on degradation of insulation resistance of MLCs under humid loading conditions.