Synthesis of magnetic carrier sub-microparticles with high stability through carbon reduction and solation coating methods

This paper presents a novel approach in synthesizing SiO_2-Fe_3O_4magnetic carrier with high stability.The Fe_3O_4 magnetic powders were synthesized via onestep method named carbon reduction method. The advantages of the methods are of simple process, none lead-in pollution agent, low cost and adaptation to large-lot production. The stability of the magnetic powders is improved through modifying the Fe_3O_4 with SiO_2 in solation method.The results of the characterizations show that the superparamagnetic SiO_2-Fe_3O_4sub-microparticles（~600 nm）with saturation intensity of 36.4 m A·m~2·g~（-1）are obtained successfully. Moreover, the quantitating, repeatability and high stability of the carbon reduction method are demonstrated as well.