We studied the sintering behavior and magnetic properties of Ni_0.60‐yCu_yZn_0.42Fe_1.98O_3.99 ferrites. The shrinkage is shifted toward lower temperature with increasing Cu content y. The addition of Bi₂O₃ sintering aid induces enhanced shrinkage at T < 900°C and dense ceramics are obtained after sintering at 900°C. Such ferrites exhibit a permeability of µ = 135‐250 depending on the composition, sintering temperature and concentration of sintering additive. Ferrites with y = 0.20 show a high Curie temperature of T_c = 307°C. Multilayer inductors were fabricated and cofired at 900°C using ferrite tapes without and with 0.75 wt% Bi₂O₃. The compatibility of ferrite tapes with different metal pastes (Ag, AgPd, and Au) was evaluated. Ferrite tapes were also integrated between layers of low‐k dielectric CT708 tapes and successfully cofired at 900°C. Preliminary tests indicate that the multilayer inductors can be operated up to temperatures of 250°C. This demonstrates that high‐T_c Ni‐Cu‐Zn ferrites are promising magnetic materials for inductive components for high operating temperatures.

中文翻译：

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高居里温度的Ni-Cu-Zn铁氧体用于工作温度升高的多层电感器

我们研究了Ni _0.60-y Cu _y Zn _0.42 Fe _1.98 O _3.99铁氧体的烧结行为和磁性能。随着Cu含量y的增加，收缩率向较低温度移动。Bi ₂ O ₃烧结助剂的加入导致在T  <900°C时收缩率增加，在900°C烧结后获得致密陶瓷。此类铁氧体的磁导率 取决于组成，烧结温度和烧结添加剂的浓度，为µ = 135-250。y  = 0.20的铁氧体显示居里温度T _c高 ＝ 307℃。制备多层电感器，并使用不含和含0.75 wt％Bi ₂ O _3的铁氧体带在900°C下共烧。评估了铁氧体带与不同金属浆料（Ag，AgPd和Au）的相容性。铁氧体磁带也被集成在低k介电CT708磁带层之间，并在900°C下成功共烧。初步测试表明，多层电感器可以在高达250°C的温度下工作。这表明高T _c Ni-Cu-Zn铁氧体是用于高温工作的电感组件的有前途的磁性材料。