Preparation And Properties Of Zn-γ-Fe₂O₃ Magnetic Sol-gel System

Under certain conditions, the ionic magnetic fluids of ZnFe2O4 can be presented gel state.γ-Fe2O3 magnetic nanoparticles were pepared by the precipitation and Prepared by Zn, Fe salt solutions, then can be obtained Zn-γ-Fe2O3 magnetic nanoparticles. Prepared the system of the gel and sol by self-formed method. The crystal structure, element ratio and morphology of the Zn-γ-Fe2O3 were analyzed by XRD, EDX, XPS, TEM, respectively. The results show that the particles are preferable crystal and statistical analysis show that particle's size distribution is satisfy lognormal distribution. The median value of Zn-γ-FeO3 magnetic particles are 7.14nm.The magnetization of the system of Zn-γ-Fe2O3 magnetic nanoparticles and magnetic colloid in the two states (gel, sol) were Measured by VSM, the magnetic properties of magnetic gel and magnetic sol are different, this difference comes from the internal network structure of magnetic gel, when the colloid at the gel state, the particles are limited by network structure of magnetic gel, the magnetic nanoparticle moment can not completely turn to the field direction under the applied field; the magnetic particles homodisperse in the base fluid when the colloid at sol state,as the applied field acted on magnetic particles, magnetic moments were easier to bias field direction so the magnetic sol state is stronger than the gel state, while Zn-γ-Fe2O3 sol and near gel were measured by the same method of Zn-γ-Fe2O3 sol and gel have been, results show that the sol state magnetic magnetism were stronger than near gel; and used similar methods to test the ZnFe2O4 paramagnetic gel, showing the gel is greater than the magnetic sol on magnetization. Therefore, ZnFe2O4 paramagnetic gel and Zn-γ-Fe2O3 gel were different properties on magnetization in gel, sol state. The same Q value ZnFe2O4 gel system, the greater the volume fraction of ZnFe2O4 gel, the poor the sol-gel on the magnetization. But showing that the greater the volume fraction of gel, the higher the grid density, under the applied field, the induced magnetic moment of particles deflection is relatively difficult. So a large volume fraction of gel were weak than smaller the volume fraction gel on magnetization, indicating high concentrations of magnetic gel on the magnetic influence. When the colloid in the sol state, as the repair of the grid, the sol would gradually form near gel, particles is limited to a number of local grid area in the near gel, when the magnetic field, the particles magnetic moment deflection is limited by the grid, the greater the volume fraction of the gel, the more the small grid of the near gel. particles moment deflect orientation in the grid is relatively poor, leading to magnetic low.The magneto-optical effect of the Zn-γ-Fe2O3 magnetic liquid and near gel system is measured, present different transmission rate of light between magnetic fluids and near gel. according to the gel structure and analyzing this microscopic mechanism of near gel, preliminary explanation the light transmittance of near gel system.