Study On Preparation And Properties Of The Composite Electromagnetic Wave Absorbing Material With Magnetic Fly-ash Hollow Cenosphere As Nucleus

With the development of modern science and technology, electronic information industry flourished quickly, and various electronic production bring convenience to us. But subsequently, electromagnetic radiation are around us is harmful to human. Nowadays, electromagnetic wave absorbers material is used widely and the study about it is increasing. It's a hot spot to find a low cost approach that can used in practical production. Composite electromagnetic wave absorbers material coated with magnetic fly-ash hollow cenoshere is my research topic, and it meets the current development of the absorbing materials and have good prospects.In this paper, there are two stages in the test. The first stage is to find a good method to prepareγ-Fe2O3 nano-particles. The second stage is preparing composite electromagnetic wave absorbing material with magnetic fly-ash hollow cenoshere as nucleus.Two methods are adopted in the first stage for the test.One is thatγ-Fe2O3 nano-particles preparing by the method of condensing backflow, which is good appearance and uniform particles but power consumption, durative, not dispersive.The other is solid-phase reaction. The main process is that using Fe(NO3)3·9H2O, tartaric acid as the raw material, andγ-Fe2O3 nano-particles were made by ball mill, and then dried at 80℃, get the precursors at last. The precursors were dried at 300℃, 400℃for 1 hour and get steady crystallineγ-Fe2O3 nano-particles. The process calcining precursors was detected by TG-DTA, the appearance and component of the sample were characterized by SEM, micromechanism was reviewed by XRD and TEM, and the magnetism was studied by VEM. And uniform pureγ-Fe2O3 nano-particles with size of 15-30 nm are obtained.At the second stage is preparing composite absorbent, then making electromagnetic waves materials. The hollow cenosheres are put into reactant at the beginning of the reaction. Composite layers are formed betweenγ-Fe2O3 nano-particles and ferrite in the fly-ash hollow cenosheres that coated with magnetic. It conduces the attenuation of electromagnetic wave. Then, the samples were characterized by SEM, micromechanism was reviewed by XRD and TEM, and the absorbing effectiveness is 31dB. At last, absorbent are mixed into basic materials at a certain proportion.The results show that this solid-phase reaction technique is simple, convenient, having large output and practical value.