Of Ltcc Magnetic Dielectric Preparation And Electromagnetic Properties Of Composite Ceramics

Composite electronic materials exhibit both magnetic and dielectric properties due to their unusual physics and multi-functions. Recently, with the development of low-temperature co-fired ceramics (LTCC) technology and integrated chip elements, such composite materials with significant permeability and permittivity were extensively researched. Because of their both inductive and capacitive functions, these composite materials can be used to manufacture truly integrated passive complex elements, such as filters, by a single material, which has obvious advantages in reducing the space occupied by printed circuit boards and further allowing the miniaturization of the integrated elements. So they have potential application in the production of electronic devices in future. However, development of a high-quality composite material with simultaneous ferromagnetic and ferroelectric characteristics is an ever challenging aspect for investigation. In this paper, we prepared the xTi02+(1-x)Ni0.2Cu0.2Zn0.620(Fe2O3)0.98 (NiCuZn ferrite) (0≤x≤60 wt.%) and the xBao.6Sro.4Ti03 (BST)+(1-x)Ni0.2Cu0.2Zn0.620(Fe2O3)0.98(NiCuZn ferrite) (0≤x≤60wt.%) composite ceramics respectively, with addition of Bi2O3 as a sintering agent. Here, NiCuZn ferrite is chosen as a ferrite phase because of its high permeability, high curie temperature, high frequency, and relative low loss tangent. TiO2 is a dielectric phase due to its high dielectric constant and relatively low dielectric loss. And (BaSr)TiO3 is a dielectric compound with a large figure of merit and superior dielectric properties. The sintering behaviors, phases, microstructures, and electromagnetic properties of studied systems were investigated.A series of xTi02+(1-x)Ni0.2Cu0.2Zn0.62O(Fe2O3)0.98 (NiCuZn ferrite) (0≤x≤60 wt.%) composite ceramics were primarily prepared by a solid-state reaction method. With addition of 3 wt.% Bi2O3, all the ceramics can be sintered at 900℃. The effects of composition x on the sintering behaviors, phase compositions and electromagnetic properties of TiO2+NiCuZn ferrite ceramics were investigated. X-ray diffraction (XRD) results showed that the ceramics were composed of NiCuZn, Fe3Ti3O10 and TiO2 phases. Scanning electron micrographs showed that 10 wt.% TiO2-90 wt.% Ni0.2Cu0.2Zn0.620(Fe2O3)0.98 ceramics had small grain size and high density. With an increase of TiO2 content x, the value ofεr decreased and the component with 10 wt.% TiO2 had maximum relative dielectric constant. The permeability and the saturation magnetization decreased gradually with increasing TiO2 content, and the permeability curve exhibited excellent stability of frequency. The composite materials with 10 wt.% TiO2 showed typical magnetic hysteresis of the magnetic materials. For the specimens with 10 wt.% TiO2-90 wt.%Ni0.2Cu0.2Zn0.620(Fe2O3)0.98, the good dielectric (εr=50) and magnetic properties (μ=30, tanδμ=0.13) have been obtained at 900℃.xBa0.6Sr0.4TiO3 (BST)+(1-x)Ni0.2Cu0.2Zn0.620(Fe2O3)0.98 (NiCuZn ferrite) (0≤x≤60 wt.%) composite ceramics were primarily prepared by a solid-state reaction method. With addition of 3 wt.% Bi2O3, all the composite ceramics can be sintered to a density>95% of theoretical density at 925℃. The effects of composition x on the sintering behaviors, phase compositions and electromagnetic properties of BST+NiCuZn ferrite composite materials were investigated. X-ray diffraction (XRD) results showed that the composites were composed of BST and NiCuZn phases. The ions diffusion was found to take place between NiCuZn ferrite and BST, which affected the electrical properties of the ceramics. With an increase of BST content x,the dielectric constant of the composites increases and the permeability decreases. For the specimens with 40 wt.% Bao.6Sro.4Ti03-60 wt.% Ni0.2Cu0.2Zn0.62O(FeO3)0.98, the good dielectric (εr=48,tanδ|ε=0.01)and magnetic properties (μ=20.8, tanδμ|10MHz=0.03) have been obtained at 950℃. Meanwhile, it exhibited excellent frequency stability which was up to fr=100 MHz.In conclusion, the 10 wt.% TiO2-90 wt.% Ni0.2Cu0.2Zn0.62O(Fe2O3)0.98 ceramic and the 40 wt.% Bao.6Sro.4Ti03-60 wt.% Ni0.2Cu0.2Zn0.62O(Fe2O3)0.98 composite exhibit excellent integrated properties, which can be used not only as inductors and resistors but also as capacitors.