Research On Electrical And Magnetic Properties Of Composite Garnet Ferrite Sintered At Low-temperature

With the development of telecommunications and computer technology,a kind important electronic components with multilayer chip inductors have been deeply researched and got extensive applications.The Bi-CVG ferrites have better magnetic and sintering properties and especially the lower cost,and are the best choice for low sintering YIG.For this reason,this dissertation presents a systematical study on the electrical and magnetic properties of the low temperature sintered Bi-CVG ferrites and the effect of additions on it.In this dissertation,we used Y₂O₃,Fe₂O₃,Bi₂O₃,V₂O₅,CaCO₃,In₂O₃ and B₂O₃ as the raw material.The Bi-CVG ferrites have been sinstered with lower temperature. It's suggested that sintering conditions had the effect on microstructure and magnetic properties of Bi-CVG and did research the doping and sintering temperature on the laws and mechanisms of Bi-CVG series ferrite properties.In order to further researches on these influences,we also observed that the effect of different sintering temperature, soaking time and doped content of the bulk density,structure,morphology,magnetic and dielectric properties was investigated by XRD,SEM,MATS and RF impedance material analyzer.The results were outlined here with:(1) Appropriate pre-sintered temperature can effectively increase the density of ferrite,and the sintering temperature has significant effect on the stability of YIG phase and magnetic properties,but soaking time has relatively small influence on it.It is suggested that the as-prepared at 1100℃for 6h has a better properties.The average grain sizes of sample is about 2μm,ρ=5.20g/cm³,The main magnetic parameters are B_r=24.57 mT,H_c=764.4 A/m,4πM_s=343.2×10^-4T,tanδ_ε=4.34×10^-4,ε=13.92。 (2) In-substituted may improve magnetic and dielectric properties of Bi-CVG Ferrite material.This is accompanied by a significant increase in the relative density, saturation magnetization(4πMs),remanent magnetization and resistivity,and a significant reduction in coercivity,dielectric loss of the appropriate In-substitution. In-substituted accelerated crystallization and lowered sintering temperature of Bi-CVG ferrites.We found that the most optimized content of In-substituted is 0.4～0.6.(3) B-substituted may significant reduced the sintering temperature of Bi-CVG ferrite material.With a significant increase in the B-doped content,resistivity increases, dielectric loss tanδ_ε,saturation magnetization(4πMs),remanent magnetization and coercivity slight decrease.It is suggested that the as-sintered B₂ sample at 1060℃for 6h has a better electric-magnetic properties.The main electric-magnetic parameters are D=5.11g/cm³,D_R.T=97.2%,B_s=37.30mT,B_r=25.54mT,H_c=0.87kA/m,ρ=3.67×10¹⁰Ω·cm,tanδ_ε=3.94×10^-4。When keeping a high electromagnetic property,Bi-CVG composite garnet ferrites we study in this dissertation may significant lower sintering temperature.The R:Bi-CVG(R=In,B) materials can be co-fired with Ag-Pd-electrode materials and show good potential for low-temperature sintering.This kind of Bi-CVG ferrite has optimistic applying foreground.