Study On The Preparation And Magnetic Properties Of The M-type Barium Ferrite With Lower Dimensionality

Ferrite is a kind of important nonmetallic magnetic materials. Compared with metal magnetic materials, ferrite has high resistivity, high dielectric properties, high magnetic permeability at high frequency. Ferrite’s magnetic property is closely related with its structure. It has three kinds crystal structure spinel, hexagonal and garnet. The hexagonal ferrite as ultra high frequency soft magnetic materials and millimeter wave band materials, its application is very extensive. The M ferrite BaFe12O19(BaM) is a typical representative of the hexagonal ferrite. Its preparation cost is low, and it has high resistance rate, strong magnetic uniaxial anisotropy, good chemical stability and wear resistance. It has been widely used as high-density perpendicular magnetic recording medium. Because of the strong magnetic uniaxial anisotropy, ferrite’s grain size and microstructure (dimensionality) have a great influence on the magnetic performance. Therefore, how to prepare BaM powder with complete crystallization, small grain size, narrow particle size distribution, neat morphology, lower dimensionality is very important.In this paper, using coprecipitation method, reference to the role of surfactant in microemulsion method, the introduction of surfactant controls the ferrite precursor microstructure. After low temperature calcination, the precursor transform into the BaM powder with complete crystallization, small grain size, narrow particle size distribution, neat morphology, large diameter-thick ratio. The BaM fiber was prepared by calcineing the precursor fiber which was prepared by electrostatic spinning.The phases, microstructure and magnetic properties of the BaM powders prepared by coprecipitation method were investigated by XRD, SEM and VSM. Adding surfactant, extended mixing time and increasing the calcination temperature is helpful to get BaM powder with high crystallinity, hexagonal lamellar structure, good magnetic properties. Improve precipitation reaction temperature, can effectively reduce the calcination temperature, but will reduce the Ms and Mr of the BaM powders Different surfactant has different effect, the effect of PAA is best, Ms increased by 20.9%, the Mr increased by27.3%The phases and microstructure of the BaM fibers prepared by electrostatic spinning method were investigated by XRD and SEM. The diameter of electrostatic spinning fiber increases with the increasing of organic matter content in the electrostatic spinning dope. The particle size of BaM fiber increases with the increasing of calcination temperature, and BaM fiber’s overall structure is damaged. Change the electrostatic spinning dope solvent composition to ethanol:water=5:1, BaM hollow fiber can be gotten directly without coaxial needle.