Oxidation Behaver of Fe_3O_4 Coaded with SiO_2 by Fluidized CVD
ZHU Yi-Hua;WU Qiu-Fang;LI Chun-Zhong(Institute of Technical Chemistry and Physics, East China University of Science and Technology,Shanghai 200237, China)
Fe_3O_4 magnetic powder coated with uniform SiO_2 layer was obtained by fluidized CVDtechnique. The oxidation mechanism and the kinetics of the SiO2 coated Fe3O4 were investigated.The results show that the mechanism of oxidation of the SiO2 coated Fe3O4 is inferred as phaseboundary reaction, spherical symmetry. The activation energy is increased with increasing silicacontent. The silica protect layer on the Fe3O4 magnetic powder formed by fluidized CVD techniquecan improve the oxidation-resistance of Fe3O4.