吸附钡铁氧体的多孔陶粒吸波材料制备及其性能

Preparation and Performances of Porous Electro-magnetic Wave Absorbing Ceramisite Coated with Barium Ferrite

以硝酸铁、硝酸钡、柠檬酸为原料,采用溶胶-凝胶法合成钡铁氧体溶胶,将其吸附于多孔陶粒表面和微孔中,经焙烧制备得到电磁吸波功能陶粒;再将该功能陶粒用作集料制备新型水泥基复合吸波材料。研究了合成的钡铁氧体的物相、形貌、复介电常数和复磁导率;结果表明合成的钡铁氧体纯度高,合成温度对其结晶度和晶体形貌有影响,经1000℃煅烧制得的钡铁氧体具有良好的吸波能力;对制得的功能陶粒进行了测试,结果表明钡铁氧体能包覆至陶粒表面和孔壁上;采用弓形法测得的功能陶粒水泥基吸波材料在8~18GHz频率范围内的电磁波反射率明显优于采用碎石和普通陶粒制备的试样。

Barium ferrite was prepared by sol-gel method with ferric nitrate,barium nitrate and citric acid.And micro-wave absorbing functional ceramisite was obtained by coating the synthesized barium ferrite gel on the surface of porous ceramisite and then calcining.Furthermore,a new type of cement-based micro-wave absorbing material was prepared using the functional ceramisite as aggregate.The composition,morphology,complex permittivity and complex permeability of the synthesized barium ferrite were investigated by means of X-ray diffraction analysis（XRD）,scanning electron microscope（SEM）,and Vector Network Analyzer（VNA）,respectively.Results show that its purity is high,and calcination temperature has effect on its crystallization degree and particle morphology;Barium ferrite prepared at 1000℃ shows good micro-wave absorbing ability.XRD and SEM-EDS were used to characterize functional ceramisite,and the results show that barium ferrite can be tightly coated on the surface and pore wall of porous ceramisite.The reflectivity of cement-based composite was measured by Naval Research Laboratory（NRL）testing system in the frequency ranges from 8 to 18 GHz.The acquired data is between-8.9 to-9.8 dB,which are obviously superior to those specimens prepared with gravel and ordinary ceramisite.