ELECTRICAL AND MAGNETIC PROPERTIES OF LOW-TEMPERATURE SINTERED xTiO2+(1-x)Ni0.2Cu0.2Zn0.62O(Fe2O3)0.98 CERAMICS

Abstract

For the purpose of multi-layer chip electromagnetic interference (EMI) filters, a series of x TiO 2 + (1 - x) Ni 0.2 Cu 0.2 Zn 0.62 O ( Fe 2 O 3)0.98 ( NiCuZn ferrite) (0 ≤ x ≤ 60 wt .%) composite ceramics were primarily prepared by a solid-state reaction method. With addition of 3 wt.% Bi 2 O 3, all the ceramics can be sintered at 900°C. The effects of composition x on the sintering behaviors, phase compositions and electromagnetic properties of TiO 2+ NiCuZn ferrite ceramics were investigated. The X-ray diffraction (XRD) results showed that the ceramics were composed of NiCuZn , Fe 3 Ti 3 O 10 and TiO 2 phases. Scanning electron micrographs showed that 10 wt.% TiO 2 to 90 wt.% Ni 0.2 Cu 0.2 Zn 0.62 O ( Fe 2 O 3)0.98 ceramics had small grain size and high density. With an increase of TiO 2 content x, the value of εr decreased and the component with 10 wt.% TiO 2 had maximum relative dielectric constant. The permeability and the saturation magnetization decreased gradually with increasing TiO 2 content, and the permeability curve exhibited excellent stability of frequency. The composite materials with 10 wt.% TiO 2 showed typical magnetic hysteresis of the magnetic materials. For the specimens with 10 wt.% TiO 2 to 90 wt.% Ni 0.2 Cu 0.2 Zn 0.62 O ( Fe 2 O 3)0.98, the good dielectric (εr = 50) and magnetic properties (μ = 30, tan δ| 10 MHz = 0.13) have been obtained at 900°C.