Research On Low-temperature Sintered Y-type Planar Hexagonal Ferrite

With the rapid development of modern electronic technology, the electronic components tend to chip and miniaturization gradually. At present, the mainstream developing direction is putting capacitor, inductor and resistor together into multilayer chip components with the Monolithic Structure. Ag as electrode materials must be able to sinter with such components in low-temperature. Today, electronic technology has developed to high frequency. Because of the excessive loss,the traditional spinel structure of Ni-Cu-Zn ferrite can’t meet the needs of application in very high frequency. Because of the magnetocrystalline anisotropy which is caused by its structure, in very high frequency segment Y-type planar hexagonal ferrite material with high initial permeability, high cut-off frequency, quality factor, high stability, low magnetic loss and low dielectric loss is expected to become the ideal material of multilayer chip inductor.This paper adopted the traditional solid-phase reaction which can be used for large-scale industrialized production to make Y-type planar hexagonal ferrite material. Some innovative and exploratory study of the formula, process and doping was done in low temperature sintering. Main content and results as follows:1. The influence of low temperature sintering electromagnetic performance by ion doping in Y-type planar hexagonal ferrite materials was studied. It was found that with increasing Cu content grain size increased gradually, and sintering density decreased gradually. Initial permeability increased with the increase of Cu content as a whole. When Cu content increased to a certain degree,the depletion would increase significantly. Initial permeability increased with the increase of content of Zn on the whole. Overhigh content of Zn could lead to lower cut-off frequency. Considering comprehensive parameter the best formula was Ba2Co0.2Zn0.9Cu0.9Fe12O22.Sintering temperature was 900℃.2. Bi2O3 was added in order to reduce the sintering temperature and improve the densification. It was found that the effect of Bi2O3 on permeability was unremarkable. When the content of Bi2O3 was 2.5 wt%, the permittivity reached its minimum. Meanwhile, the dielectric loss and magnetic loss was below 10-2. The static permeability was 7.98, the static permittivity was 14.10, the magnetic loss was 1.28×10-2 and dielectric loss was 5.91×10-3 at 200 MHz.3. Bi2O3-H3BO3-Si O2-ZnO glass was added instead of the Bi2O3. When the content of Bi2O3-H3BO3-SiO2-ZnO glass was 0.8wt%, the sintering temperature could further reduce to 860℃. Comparing with the Bi2O3 doping, the permeability and the permittivity was increased.