Study On Nanometer Ferrites Synthesized By Solid-State Reaction And Microwave Absorption Coatings

The precursors of basic carbonates and ferric hydrate for ferrite were prepared by solid-state reaction at room temperature and characterized by TG-DSC. The nanometer spinel ferrites including single ferrites such as ZnFe₂O₄, CoFe₂O₄ and NiFe₂O₄, compound ferrites such as Co-Zn, Ni-Zn ferrites and the ferrites doped rear earth elements such as ZnFe_2-xY_xO₄ (x=0.00, 0.005, 0.01, 0.05, 0.1) ZnFe_1.95RE_0.05O₄, Co_0.5Zn_0.5Fe_1.95RE_0.05O₄, Ni_0.5Zn_0.5Fe_1.95RE_0.05O₄ (RE=La, Sm, Pr, Nd and Gd) with the average size of 62nm were obtained by microwave heating at 600W and 10min and thermolysis at 550℃and were studied by Laser Granularity Analyzer, XRD,SEM and TEM.The electromagnetic loss property was studied by the relative dielectric constant and relative magnetic permeability of all samples in 100¹800MHz. The results show that the Co_0.5Zn_0.5Fe₂O₄, Ni_0.5Zn_0.5Fe₂O₄ ferrites has the better electromagnetic loss property in the Co-Zn, Ni-Zn ferrites in 100¹800MHz and that Fe³⁺ was substituted small by some rear earth elements in ZnFe₂O₄ Co_0.5Zn_0.5Fe₂O₄, Ni_0.5Zn_0.5Fe₂O₄ that can increase properly the electromagnetic loss property of materials in 100¹800MHz.Microwave-absorption coatings were prepared using epoxy resins as adhesive, the prepared ferrites with the better electromagnetic loss property as microwave absorber. The microwave-absorption property has been searched by the measuring of absorptivity of microwave. The results are consistent with the electromagnetic loss property.