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Y-type hexagonal ferrite due to the anisotropy of its structure, so that the application having a high initial permeability, excellent magnetic properties of a high quality factor, and a high cutoff frequency in the VHF band (300 ~ 800MHz), is the material of choice for the preparation of chip inductors. Currently, the main direction of development of the chip inductor multilayer chip inductors, the key technology is to find co-fired with the conductor, low-grade fever (Ts ~ 900 ℃) high-performance soft magnetic ferrite materials. In this paper, the chemical coprecipitation prepared ferrite precursor, first develop a reasonable program of experiments, optimization of experimental conditions by changing the single factor method affect the the precursor precipitation particles key process conditions pH value, temperature (T), stirring rate (R), the flow rate of the salt solution (V), the concentration of carbonate ions, and a dispersing agent concentration of SDBS optimization. Characterization of sediment particles by LPS (laser particle size analyzer) particle size distribution, we can see, the experimental conditions were as follows: pH = 10.50, T = 50 ° C, R = 300 rpm, V = 0.35 ml, SDBS = 0.3 ~~ 1.0g / L particle size distribution range 2.28-4.47μm, D50 = 3.0μm; pressed into the precursor powders calcined at 900 ℃ toroid sintering at 1000 ℃ using XRD analysis SDBS concentration phase of ferrite material, showed that the concentration of SDBS 0.3g / L is appropriate, using a vibrating sample magnetometer (VSM) HP4291A impedance analyzer measurement hysteresis loops and magnetic spectrum characterization ferrite magnetic energy can be seen, excellent Ferrites prepared under optimized conditions The experimental conditions: pH = 10.50, T = 50 ° C, R = 300 rpm, V = 0.35 ml, SBDS = 0.3g / L. Hysteresis loop parameters: σs ≈ 29.72A · m2 · kg-1, Hc ≈ 4.11/kA · m-1, σr ≈ 7.74A · m2 · kg-1, the frequency characteristics of the good, in the 100MHz frequency, μi ≈ 9, Q ≈ 18. The precursor is calcined at 600 to 1050 ° C after sintering at 1000 ℃ XRD patterns for all samples tested, and the TG-DTA curves and the scanning electron micrograph (SEM) analysis after calcination of the sample at each temperature composition and microstructure change reveals the formation of Y-type hexagonal ferrite crystal structure changes in the law, indicating that the samples calcined at low temperature (900 ℃) to form pure phase Y-type hexagonal ferrite, and pointed out that the the process of transformation of its crystal structure; magnetic test results show that the prepared sample having a good magnetic Bibi saturation magnetization of the sample as the calcination temperature increased, the first reduction of the initial permeability corresponding toroid increase , when T = 900 ℃, σs ≈ 17.262A · m2 · kg-1, of Hc ≈ 5.146kA · m-1, in the 100MHz frequency μi ≈ 3.7, Q ≈ 13.4. Ferrite low temperature sintering, sintering aids added to the calcined powder of Bi2O3, adding 0.5wt%, 1.0wt%, 1.5 wt%, 2.0 wt% of iron will add different amounts of sintering aids Oxygen sintered at different temperatures and drainage method test magnet relative density, sintering temperature of 800 ° C, 850 ° C, 900 ° C, 950 ° C, the results show that adding 1.0wt% Bi2O3 sample sintered at 900 ℃ × 4h can achieve ferrite cryogenic densification, the relative density of 95%, the test magnetic spectrum characterization magnetic seen: μi ≈ 10, Q ≈ 13.
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