Carbonyl iron powders with average diameters of 6μm and 1μm were coated,respectively,with TiO2 film using the sol-gel method.A vector network analyzer was used to measure the complex dielectric permittivity,complex magnetic permeability,and absorption coefficient of the composites composed of carbonyl iron particles and paraffin,where the carbonyl iron particles were bare or TiO2 coated.The results show that the TiO2 coaitng can increase the complex magnetic permeability and the complex dielectric constant of the composite with 1μm diameter carbonyl iron particles,and enhance its microwave absorption coefficient.We suggest that the TiO2 film can prevent eddy currents among the small carbonyl iron particles,which increases its microwave absorption coefficient.%本文采用溶胶-凝胶法,分别在粒径为6μm和1μm的羰基铁粉表面成功包覆了一层二氧化钛薄膜;利用矢量网络分析仪测量了羰基铁粉和石蜡所制成的复合材料的电磁参数,对比分析了二氧化钛包覆前后羰基铁粉复合材料在微波频段的复介电常数、复磁导率和微波吸收性能的变化.实验结果表明:二氧化钛包覆层能有效地增大粒径为1μm的羰基铁粉的复磁导率和复介电常数,改善小粒径羰基铁粉的微波吸收性能.通过分析认为二氧化钛包覆层能有效地阻隔颗粒间涡流的形成,由此能很好地解释二氧化钛包覆层对1μm羰基铁粉微波吸收性能的增强效果.
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