분무 열분해에 의한 Ba1-xSrxFe12O19계 자성 미립자의 제조 및 특성 변화

Abstract

Magnetic particles with alternating magnetic field are expected to be useful as thermoseeds in hyperthermic cancer treatment, since they can be targeted and confined to the cancer site. Hard magnetic ferrites such as barium ferrite and strontium ferrite are good candidates for thermoseeds of hyperthermia because of their great hysteresis loss. In order to verify the effect of Sr-substitution to Ba-site, synthesized Ba1-x,Srx,Fe12O19 microspheres with various compositions through spray pyrolysis followed by sol synthesis using barium nitrate, strontium acetate and iron nitrate. Coercive force was increased with increasing substitution amount of Sr whereas magnetic saturation was almost constant. Spherical microspheres with average diameter of 11.7-17.0 pm were produced by spray pyrolysis at 400?1000?C. The mean size was dependent on the pyrolysis temperature and flow rate of carrier gas. In order to obtain a single phase of SrFe12O19 crystal, the spray pyrolyzed spheres were undertaken subsequent heat-treatment above 10000. During the subsequent heat-treatment, however, spherical microspheres were agglomerated because of necking between particles. Further study has to be continued working on synthesis of pure SrFe12O19 ( crystal by means of improvement of pyrolysis temperature scheme and extend the heating period.