Research On Property & Low Temperature Sintering Of Microwave YIG Ferrites

Microwave YIG ferrites are the key materials of modern electronic industry and information industry. With the development of microwave telecommunication towards miniaturization, light weight, integrated all-in-one, it is necessary of material owning high power load hc, low dielectric loss tgδ_ε, narrow ferromagnetic resonance line widthâ–³H, and better stability, etc. Moreover, it is the key of materials sintering together with common electrode at low temperature. In this paper, we deeply study on the ionic replacement & low temperature sintering process of microwave YIG ferrites.The writer explains the microwave YIG ferrite's magnetic origin from its crystsl structure & the ionic replacement, and analyzes systematicly its mainly performance parameters, which supply the theory of the low temperature sintering YIG ferrites.The writer studies in the round the low temperature sintering process of YIG, and puts forward its elaborate process flow.In this paper, we have prepared the fine combination property YBiCaVIG microwave garnet ferrites at low temperture sintering by traditional oxide method. And the key factors that influence its properties are researched.The result shows that, using ions V⁵⁺, Bi³⁺, etc, substituted YIG can reduce evidently its densification sintering temperture. The sample Y_1.05Bi_0.75Ca_1.2V_0.6Fe_4.4O₁₂ at 1100℃sintering, its relative density is above 98%, this temeperture reduces over 300℃more than polycrystalpure YIG ferrites. In materials properties respect, the series samples, whose formula is Y_1.8-yBi_yCa_1.2V_0.6Fe_4.4O₁₂(y=0.25,0.5,0.75,1.0), in respective densification sintering temperture, the combination property of y=0.75 sample, Hc=4.02Oe, 4Ï€Ms=55mT,â–³H=9.85kA/m, Tc=223℃,ρ4.3×10⁸Ω·cm, tgδ_ε=4.5×10^-4, is better than any others. By XRD,SEM analyzing shows, the sample of y=0.75, at 1100℃sintering, crystallize completely, crystal grains well-distributed, air hole less,etc. The microwave garnet ferrite can sinter together with common electrode Ag-Pd alloy, and be suitable for performance requirement of the low frequency microwave device.Besides, we have prepared the Bi-YIG powder by sol-gel method, and its heat treatment is reseached.