Hexagonal Ferrite Synthesis And Device Application Research

With the rapid development of communication technology, electronic devices develop toward small-scale, high-frequency, low loss, multi-function and high reliability, which put forward higher requirements for device materials. Taking into account the excellent electromagnetic properties of hexagonal magnetoplumbite ferrite and the ceramic casting techniques, which was being widely used in electronic components production, this paper takes SrFe12O19 hexagonal ferrites as research object, mainly utilizing hydrothermal method to prepare high purity, good crystal morphology, high in-plane anisotropy and uniform SrFe12O19 microcrystalline hexagonal plate for the purpose of exploring the influence of formulation and process conditions for forming phase and shape. Under the premise of the successful synthesis of SrFe12O19 microcrystalline with preferable morphology, combining with powder prepared by traditional solid phase ball-milling method, for the first time we carry out the research of taking microcrystalline hexagonal plate as a template and mixing ingredients in proportion to cast self-assembly flow. Then finally we discuss its study and development in device application.The main contents are as follows:First, we explore the influence of the proportion of the raw materials on the formulation of hydrothermal synthesis product. The influence of the molar ratio of hydroxide nitrate and strontium iron on the resultant phase composition is studied, to find the optimum ratio.Second, we explore the effects of hydrothermal synthesis conditions on the product. We conduct the research on material phase morphology’s dependence on the hydrothermal synthesis temperature, holding time, concentration, solvent, nitrogen pressure and the product heat treatment. We find the optimal temperature, holding time, concentration, then prepare the sheet-like hexagonal crystallites with good morphology and uniformity.Third, on the basis of in-depth understanding of the solid phase reaction and casting mechanism, we mix the hexagonal platelets produced by hydrothermal synthesis with two-feed mills calcined by solid phase method, orient platelets by casting thermoforming technology, and study the process conditions of grain self-assembly growing.Fourth, combining with material performance parameters, we design a microstrip line Y junction circulator, of which the center frequency is 16 GHz, the insertion loss is less than 1.1 dB, return loss and isolation greater than 27 dB.