由於可攜式電子產品不斷往多功能方向發展，使得其操作電壓多樣化，進而使得小型化功率晶片電感之需求大增，已成為小型化直流電源轉換器之關鍵元組件，因此如何開發具高導磁係數及優異直流疊加特性之軟性磁性材料，便成為重要之研究課題。本研究利用傳統固態反應法製備不同配方之鎳銅鋅鐵氧磁體，化學組成為Ni0.42Cu0.13+XZn0.45Fe2-XO4；x=0, 0.01, 0.02, 0.04, 0.07, 0.1。探討不同生胚密度、冷卻速率與化學組成對鎳銅鋅鐵氧磁體微結構、磁性質及直流疊加特性之影響。結果發現鎳銅鋅鐵氧磁體可藉由加快冷卻速率或增加氧化銅含量使晶界上有CuO及Cu2O析出，藉由CuO與Cu2O之共晶反應產生液相，進而促進液相燒結之進行，使得燒結最大緻密化溫度下降。在晶界處析出之富銅二次相形成非磁性層，降低作用於鎳銅鋅鐵氧磁體晶粒上之有效磁場強度，進而提升鎳銅鋅鐵氧磁體在磁場作用時之直流疊加特性。

In this study, the NiCuZn ferrites with the chemical compositions of Ni0.42Cu0.13+XZn0.45Fe2-XO4；x=0, 0.01, 0.02, 0.04, 0.07, 0.1 were prepared using conventional solid-state reaction. The effects of different cooling rates and different chemical compositions of the NiCuZn ferriteson the microstructure, magnetic properties and DC superposition characteristics were investigated. The results showed that the increase of the cooling rate or CuO content in the NiCuZn ferrites led to the precipitation of copper-rich phase at the grain boundaries. The liquid phase resulted from the melting of copper-rich phase during the sintering promoted the liquid phase densification and hence lowering the maximum densification rate temperature.The non-magnetic copper-rich secondary phase at the grain boundaries reduced the effective magnetic field applied on the ferrite grain, and hence enhancing the DC superposition characteristics at low magnetic field. A NiCuZn ferrite with superior initial permeability and DC superposition characteristic can be obtained by changing the cooling rates and CuO content to adjust the non-magnetic copper-rich precipitate thickness at the grain boundaries.

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