Microwave Absorption Performances Of Soymeal-derived Activated Carbon Composite With NiFe₂O₄ And NiCo

Soymeal is the by-products in soybean oil extracted processing,which is renewable,easy visible,low-price.soymeal-derived actived carbon has relatively high specific surface area and porous microstructure.porous carbon materials（PC）have the high dielectric constant because of the excellent conductivity.However,as a wave absorbing material,it only has a high relative dielectric constant,which will cause its own high frequency electromagnetic wave loss performance is very poor.It is found that PC and magnetic materials can be combined to adjust the electromagnetic parameters,and the resulting composite material has excellent electromagnetic wave loss performance.In this paper,PC was successfully synthesized by KOH activted method.NiFe₂O₄/PC composites and NiCo/PC composites were prepared,to adjusted the electromagnetic parameters and improve the microwave absorption performance of the composite materials.The main contents are as follows:The NiFe₂O₄ and different proportions of NiFe₂O₄/PC have been synthesized by hydrothermal method.With the gradual increase of NiFe₂O₄,the PC in NiFe₂O₄/PC composite material was gradually covered by NiFe₂O₄.The electromagnetic parameters of the sample/paraffin mixture were tested,and calculated the reflection loss.The results showed that NiFe₂O₄/PC-1/1 had excellent reflection loss performance.When the matching thickness is 1.7mm,the reflection loss intensity can reach-43.1 dB.The corresponding effective absorption bandwidth（the part with the reflection loss intensity less than-10 dB）is 3.4 GHz（7.9-11.3 GHz）,and the reflection loss rate reaches 90%Moreover,the reflection loss values less than-20 dB（99%absorption）were observed at some frequency ranges with the thickness of 1.0-4.0 mm.The NiCo/PC have been synthesized by hydrothermal and calcination reduction method.The results showed that NiCo nanoparticles grew and crystallized on PC and distributed evenly.The number of large NiCo particles increased with the decrease of NiCo graduallyand even lead to agglomeration.The electromagnetic parameters of the sample/paraffin mixture were tested,and calculated the reflection loss.The results indicated that NiCo/PC-0.5/1 showed the good microwave absorption.When the matching thickness is 2.2 mm,the reflection loss intensity can reach-54.8 dB.The corresponding effective absorption bandwidth is 2.2 GHz（5.7-7.9 GHz）,and the reflection loss rate reaches 90%.