Microstructure–Property Relationships for Low‐Voltage Varistors

The low‐voltage varistors with various layer thickness are prepared by laminating thin ZnO‐based ceramic layers and AgPd electrodes together. The breakdown voltage dose not exhibit linear relationship with layer thickness. It is due to that the presence of the AgPd electrodes enhances the growth of ZnO grains. As some ZnO grains are large enough to touch the upper and lower electrodes, the breakdown voltage of the varistor is only 3.7 V. The nonlinear coefficient of the low‐voltage varistor is 33. Such nonlinear current–voltage behavior is mainly contributed by the interface between the AgPd electrode and ZnO grains.