Study On Preparation And Property Of Ba-Ferrite Hollow Microspheres

Core-shell composite particles consisting of a core of Polystyrene (PS) and a shell of Ba-ferrite precursor(BFP) were prepared by way of heterogeneous nucleation, and the yielded composite particles were heat-treated. The PS, composite particles and hollow microspheres were characterized by zetaPALS Zeta potential/particles size analysis instrument, infrared spectroscopy, thermo-gravimetric analysis-differential scanning calorimeter, X-ray diffraction and transmission electron microscopy. And the static magnetic property of hollow microspheres was characterized by Vibration Sample Magnetometry.Polystyrene microspheres synthesized by soap-free polymerization were studied. The result showed that the zeta potential of microsphere was minus; that the dispersion and stability of microsphere was good; that the diameter of microsphere decreased with the density of initiating agent increasing when other factors were invariable.Core-shell composite particles PS/BFP were fabricated by way of heterogeneous nucleation: in the reaction system, Ba2+ and Fe3+ were absorbed on the surface of microspheres, and then the microspheres were wrapped by precipitation of Ba2+ and Fe3+ after precipitator of Ba2+ and Fe3+ added in the system. The zeta potential of core-shell composite particles were still minus, so multiple layers of BFP on the surface of microspheres could be obtained.The core-shell composite particles PS/BFP were heat-treated. The process of heat-treatment showed that PS microspheres were decomposed about 300℃, and Ba-ferrite hollow microphere was obtained about 750℃. With heat treatment temperature increasing, the saturation magnetization increased.