| Summary: | 碩士 === 國立成功大學 === 資源工程學系碩博士班 === 101 === The effects of the addition of Co3O4 addition on microstructure and electrical properties of Cu-Zn-ferrites were investigated. The CuZn ferrites with the compositions of (CuO)0.2(ZnO)0.8(Co3O4)x/3 (Fe2O3) 0.986-2x; x = 0 , 0.02, 0.04, 0.08, 0.1, and (CuO)0.2(ZnO)0.8-x(Co3O4)x/3 (Fe2O3) 0.986; x = 0.02, 0.04, 0.08, 0.1 were synthesized using solid state reaction. It was observed that the addition of cobalt will change the amounts and distribution of the Cu2+, Cu+, Fe2+, and Fe3+ in the grain and grain boundary. For the first composition, the segregation of copper ions at the grain boundary was observed as the substitution of cobalt was increased. Moreover, as the x value was increased above 0.04, the second phases of CuO and ZnO were found. For the second composition, the amount of copper ions near the grain boundary decreased with increasing x value. The different amounts and distribution of the Cu2+, Cu+, Fe2+, and Fe3+ in the grain and grain boundary for the samples added with different amounts of cobalt changed the conductivity activation energies of the grain and grain boundary, and hence affected the space polarization and the dielectric properties.
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