Study On Preparation Technology Of Textured M-type Hexagonal Ferrite Substrate Materials

Nowadays with the rapid development of electronic materials,magnetic materials occupy an increasingly important position.However,compared with the advanced countries such as the United States and Japan,the magnetic material industry in China is still facing the problem of low management level and relatively backward manufacturing technique.As the electronic components being developed towards high-frequency,miniaturization,multifunctional and chip-based,higher demands are placed on magnetic materials,especially on ferrite material and other electronic materials.The M-type hexagonal strontium ferrite material is a typical magnetoplumbite ferrite material.The M-type hexagonal strontium ferrite has excellent performances such as superior magnetic properties,high coercivity,high saturation magnetization,and high magneto crystalline anisotropy constants,thus,it is outstanding in the magnetic material field.In this paper,hydrothermal method was used to investigate the synthesis of SrFe₁₂O₁₉9 hexagonal ferrite,and it was aimed at producing high purity,high planar anisotropy,excellent magnetic properties,good crystal morphology,and good uniformity of M-type hexagonal platelet crystallites.The hydrothermally synthesized precursor is used as a seed crystal.In combination with a conventional solid-phase technique,the mixture is mixed in a certain proportion,and the powder prepared by the ball milling of the mixture is cast so that self-assembly growth can be achieved without applying a magnetic field.Then,a highly oriented M-type hexagonal ferrite substrate material is prepared.First,the effect of different process conditions in hydrothermal synthesis reactors and different formulation raw materials on M phase was investigated.These variables include the nitrogen pressure charged before the reaction,the reaction temperature,the incubation time during the reaction,the different molar ratios of hydroxide to nitrate,and the different molar ratios of iron and ruthenium.The synthesis conditions of M phase are of a wide range,so different synthesis conditions have a certain degree of influence on the reproducibility of reaction,the formation of impurity phase,the crystal morphology and the magnetic properties.For this reason,synthesis of M phase under different conditions was studied to find the optimal M phase synthesis conditions.Next,the M-type hexagonal ferrite powder synthesized by the hydrothermal reaction is used as a seed crystal,and is mixed into the raw material prepared by the solid phase method according to a certain ratio.A film strip with a certain thickness is discharged on a casting machine,and the film ribbon layer formed after casting is stacked and heat-pressed to form an original planar anisotropic M-type hexagonal sheet along one direction.Finally,a high degree of orientation of the substrate material is obtained.