| The preparation and application ofγ-Fe2O3 nano-particles are currently attracting considerable attention because of their excellent ferromagnetic properties. And the morphology and size of particles are important factors to influence their performance. Thereby it is still significant to find new preparation methods ofγ-Fe2O3 nano-particles.This dissertation firstly tried to prepare FexOy nano-particles by metallorganic chemical vapour deposition (MOCVD) but failed because of a key factor. After summarize the experience, thermal decomposition [Fe(C5H7O2)3] was taken to prepareγ-Fe2O3,Fe3O4 andα-Fe2O3 nano-particles. XRD,TEM,BET and VSM were taken to characterize these nano-particles. The influencing factors during the experiment were discussed and studied.The main results are as follows:Using vertical thermal decomposition method, Fe3O4 nano-particles with 13nm and 16.3nm are obtained under reaction time of 90mins,air flowing rate of 500 ml/min,reaction temperature of 250℃or 300℃. When the temperature is 350℃or 490℃,γ-Fe2O3 of 16.9 nm andα-Fe2O3 of 48.6 nm are obtained.After improved the experiment device,using lying type thermal decomposition with reaction time of 60mins and air flowing rate of 100ml/min,controlling the optimum temperature of 150℃to pump air and reaction temperature of 400℃, the 20.15 nm and 43.8509 sq·m/gγ-Fe2O3 with chain shape is obtained. When reaction time is 60mins and air flowing rate is 100ml/min, controlling the optimum temperature 250℃to pump air and reaction temperature of 350℃, the 20.23 nm and 51.9395 sq·m/gγ-Fe2O3 with good crystal is obtained.Finally,a few groups of nano-γ-Fe2O3 was chosen to test magnetic properties. When reaction time is 76mins,reaction temperature is 400℃,air flowing rate is 100ml/min and system temperature is 100℃to pump air, nano-γ-Fe2O3 is obtained which specific saturation magnetization is 61.41 emu/g and shows good magnetic response. The sample shows good superparamagnetism which can be used to targeting magnetic materials.
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