The Preparation And Electromagnetic Properties Of Absorbent Of Fe Magnetic Nanofibers By Electrochemical Deposition

In modern war,with the rapid development of radar detection technology the characteristic signal of the target of weaponry and military facilities can be easily detected and the survivability is seriously threatened.Therefore,the development of stealth technology of weapons and equipment to study new highly efficient absorbent that have the quality of light,thin thickness,frequency bandwidth,strong absorption is very urgent.On the one hand Fe magnetic nanofiber absorbent has magnetic anisotropy,thereby greatly improving the axial permeability,on the other hand,the magnetic fibers have nanoscale effect.it become a very promising absorbent because Fe magnetic nanofiber has many advantages.In this paper,Fe nanowires were fabricated by electrochemical deposition method based on AAO template.In order to fabricate Fe nanowire arrays with adjustable diameter and aspect ratio and high fill rates,the preparation of nanowires by electrodeposition was studied in detail.The effects of different electrodeposition parameters and AAO template on the preparation of nanowires were studied by the electrodeposition method of alternating-curren(AC)and direct-current(DC)respectively.The morphology,magnetic properties,electromagnetic parameters and crystal type of the prepared Fe nanowires were characterized.The relationship between the Fe nanowire arrays and Fe nanowires was investigated.A large diameter,porous nanotube was prepared by AC method.Fe nanowires arrays with small diameter and controlled aspect ratio were fabricated by DC method.The minimum diameter of Fe nanowires was 30 nm.Among a large number of conductive materials Cu is the best overall performance of metal conductive layer.The Fe nanowires and nanotubes with better performance can be prepared by constant potential method.However,it is difficult to control the aspect ratio.The length of Fe nanowires prepared by constant current method increases linearly with the deposition time under the strict experimental control so that the aspect ratio can be Controled.The length of nanowires is the largest at current density of 3-4 mA/cm~2,a total charge of 20C and diameter of 100 nm.A series of Fe nanowire arrays with different diameters were fabricated and tested in order to construct relationship between the Fe nanowire diameter and Fe nanowire array.The result shows magnetic anisotropy,Coercivity and squareness of Fe nanowire arrays with diameter of 30-40nm is larger than Fe nanowire arrays with diameter of 75-95nm.After the Fe nanowires with diameter of 70nm were annealed at different temperatures,then the magnetostatic properties and 2-18GHz electromagnetic parameters were measured.The results show that the annealing temperature has significant influence on the magnetostatic properties and electromagnetic parameters.The magnetostatic properties,electromagnetic parameters between 2-18GHz of Fe nanowire arrays with diameter of 30nm also were tested that be compared with Fe nanowire arrays with diameter of 70nm.The results show permeability of Fe nanowire arrays with diameter of 30nm in powder form have not been improved obviously,The nanowire arrays in powder form can not exert the magnetic anisotropy so that the permeability is low.