| Summary: | 碩士 === 國立屏東科技大學 === 材料工程所 === 97 === Multi-layered ceramiccapacitors (MLCC) have been developed for many years. Ag, Ag/Pd,and Ni are often used as the internal electrode, and its thickness is usually about 1~2μm. Previous studies indicatedthat the electrode migration could reduce the insulationresistance (IR) and eventually destroy the capacitors afterprolonged service.
In this study, different proportions of silver-palladium alloy used as an inner electrode are adopted to fabricate (Zn,Mg)TiO3-based (ZMT) multilayer ceramic capacitors (MLCC). The influence of heating rate, two-stages sintering, sintering method and different proportions of the Pd-Ag inner electrode on the dielectric properties of the specimens are investigated. When the pure silver is applied in ZMT MLCC as inner electrode, the two-stages sintering and microwave sintering are important roles in decreasing the concentration of Ag diffusion into dielectric layer. However, it was found that insulation resistance of sample with pure silver as inner electrodes was degraded apparently by convention sintering to compare with the silver/palladium inner electrodes or compare to microwave sintering under R.H. 85% and 85℃ measuring. For Ag electrodes by conventional sintering, it could be explained that the pure silver is easily to migrate into the dielectrics layer along grain boundary during co-firing. On the other hand, the microwave sintering also can suppress Ag diffusion into dielectric layer due to different heating mechanism. The results of ZMT-based MLCCs indicate that higher silver diffusion into dielectric layer changes dielectric properties and decreases insulation resistance.
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