Preparation Of Nano-Fe₃O₄ And Investigation Of Microwave Absorption Properties Of Its Composite Material

As a burgeoning functional material, magnetic nanophase materials attract people's emphasis more and more for the past few years. While in nowadays in which high technologys develop rapidly and synthetical new materials are urgently needed, magneticFe3O4 magnetic nanoparticles as one of magnetic nanophase materials whose development, researching and application has been highly aroused people's attention. In the present work, the preparation, composite and characterization of Fe3O4 magnetic nano-materials and mechanics analysis were studied. This thesis project for the national natural science funds project. project name for:packaging nanoscale magnetic compound materials in modified zeolite and investigation of electromagnetic corresponding action. Project approval number:50972026.In this paper, nano-Fe3O4 was prepared by corprecipitation method; The granularity, morphological and absorbing properties of the magnetite nanoparticles are characterized by XRD, SEM, TEM and complex permeability. The effects of the ferrum category and the concentration, the precipitation agent category and the concentration, the reaction time and the crystallization time, reaction temperature crystallization temperature, stirring intensity and chemical additives category to the granularity, morphological and microwave absorption property of nanosized magnetic panicles Fe3O4 were studied in thin paper. The composite materials of nano-Fe3O4 and mesoporous zeolite was prepared by Liquid precipitation method and polymerization method. The effect of different composite method to the absorbing properties of the composite materials of nano-Fe3O4 and mesoporous zeolite was studied in this paper.The results show:the ferrum category and the concentration,precipitation agent category and concentration, the reaction time and crystallization time, the reaction temperature crystallization temperature, stirring intensity all effect the granularity of nano-Fe3O4 importantly. And the absorbing properties of nano-Fe3O4 is worse along with the granule size increase. The absorbing properties of 10 nm nano-Fe3O4 is better in this paper; the chemical additives category affects the morphological of nano-Fe3O4 importantly. This paper prepared spherical nano-Fe3O4 by Oxalic acid. And the absorption property of spherical nano-Fe3O4 is better.In this paper, combining the theories of crystal formation and growth, the formation mechanism of nano-Fe3O4 is studied. And, the paper researches the mechanism of the absorption property of nano-Fe3O4. The absorbing mechanism of nano-Fe3O4 is Natural resonance, domain wall resonanced and dielectric loss. The microwave absorption property and electromagnetism parameterof nanosized Fe3O4 and the composite material were studied inthe range of 2-18GHz. The dielectric loss and hysteresis loss of nano-Fe3O4 show that the different granularity and morphological of nano-Fe3O4 has different absorbing property.scattered good spherical and around 10 nm of nano-Fe3O4 has better absorbing property in this paper.