Synthesis And Properties Research Of Micronano Spinel Ferrite

Spine ferrite MFe2O4(M=Fe, Ni, Zn, Cu et al.)is a very important magnetic material, widely applied in magnetic recording media, electronic equipment, magnetic fluid, information storage, absorbing material and used as magnetic targeting drug delivery, cell separation, biomedicine in medical treatment.This thesis describes the development of, structural characteristics, typical synthesis methods, application and magnetism impact factors of ferrite material. Spinel ZnFe2O4, NiFe2O4, NiZn ferrite and CuZn ferrite nanocrystals were synthesised under mild conditions by solvothermal, hydrothermal or template method, and focused the effect of surfactant, reaction temperature, time and other conditions on the crystal size and morophology. As-synthesized samples were characterized via XRD, VSM, SEM, TEM, BET and ICP. The results are as follows:1. The monodispersed spinel ferrite was syhtnesized by solvothermal method with ethylene glycol as solvent, and investigated the effect of additive, reaction temperature and time on properties of ZnFe2O4. With KAc as agent, the saturation magnetization of ZnFe2O4 reacted at 180℃for 36h and 200℃for 24h were 54.68emu·g-1 and 58.35emu-g-1 respectively, but as-synthesized sample at 180℃for 24h with highest specific surface,83.96 m2·g-12. The spinel ferrite NiFe2O4 was synthesised with mesoporous SiO2 as hard-template which was synthesized under acidic condition with TEOS as silica source and P123 as template. As-synthesized spinel NiFe2O4 has a good crystal structure, and average pore size is 26.72nm, while the average grain size of samples is only 20.01nm, indicating as-synthesized NiFe2O4 failed to form structure pore.3. The sponge-like NiFe2O4 cluster was synthesised by solvothermal method, using ethanol-water mixed solvents, and adding surfactant PVP and HMTA respectively or together. With the effect of surfactant, we come to the conclusion that NiFe2O4 cluster synthesized by adding PVP and HMTA together, composed of uniform and fine particles, as-synthesized sample has saturation magnetization 57.30emu-g-1, specific surface area and pore volume 91.57m2-g-1,0.26cm3-g-1 respectively.4. The nanocrystalline NiFe2O4 was synthesized by hydrothermal method using PEG as soft template. With the effect of PEG molecular weight, reaction time on NiFe2O4 nanometer particles, the result shows that as-synthesized NiFe2O4 at 180℃reacting 12h with PEG-1500 as soft template has fine spinel structure and regularer morphology with saturation magnetization 60.82emu-g-1, specific surface area and pore volume 39.25 m-g-1,0.22cm3-g-1 respectively.