| The preparation technological conditions of nanometer trimaganese tetroxide by the solvothermal method are determined through the rthogonal experiment. We have found the optimal technological conditions: filling percentage is 0.8 in the reaction, reaction temperature is 260癈,the concentration of KMnO4 is below 0.015g.mL-1,the reaction time is 10 hours. The product has been characterized with the XRD, TEM, Mastersize and the composition of the material is analyzed by the chemical method. The result shows that the concentration of KMnO4, reaction temperature are the main factors influence the particle size, the composition and crystal type are affected by the reaction temperature, the magnetism of the product reduces with the reaction temperature increasing. The particle size of MnsO4 is about 25nm,staturation magnetization is about 3.58emu.g-1 and the total manganese of the product is 71.96%.Consulting the concerned reference theory of crystal nucleus growth in solution and crystal nucleus growth in metal bath, a dynamic formula of nanometer Mn3O4 produced by the solvothermal method is deduced. It can explain the relation between the phenomena and the reaction temperature, concentration of solution on some extent.In order to investigate the mechanism of the nanometer Mn3O4, the impurities are added in the different reaction routes, then the composition and the magnetism are tested. According to the result of the test, combining the theory of Neel, distribution of metal ion in the spinel structure and the correlative theories of magnetism, the mechanism of magnetism and the factors influenced the magnetism are investigated. |
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