| The rapid development of information technology and electromagnetic pollution make people pay more attention to the study of microwave absorption materials（MAs）.How to meet the high performance and practical application requirements of the material at the same time attracts much attention.Nickel slag contains many valuable metals,such as iron,nickel,copper and cobalt,and the total iron content is up to 40%.The high-value utilization of the iron resource in the slag becomes a focal issue.The magnetite prepared from nickel slag forms multiple heterogeneous interface structures due to the presence of silicates,which enable it to be MAs.Natural rubber（NR）is often used as the substrate of MAs because of its excellent mechanical properties.In this paper,nickel slag derived Fe3O4（NSD-Fe3O4）/carbon filler/NR composites were prepared by mechanical blending method,where NR was used as the matrix and NSD-Fe3O4 and carbon filler as absorbers.The microwave absorbing（MA）properties and absorbing mechanism of the composites were studied by regulating the components of the materials,and the industrial application of MAs was explored.The results are given as follows:（1）NSD-Fe3O4 particles were prepared using nickel slag s as raw materials by a molten oxidation method,and NSD-Fe3O4/multi walled carbon nanotubes（MWCNTs）/NR composite materials were prepared using a mechanical blending method.The effects of MWCNTs content（weight ratio of MWCNTs content to natural rubber content）on the absorption performance of the composite materials w ere investigated.The NSD-Fe3O4 particles have an irregular morphology with a particle size of 0.1-1μm,and MWCNTs are fibrous in shape with a dia meter of about 10 nm.After adding 5 wt%MWCNTs,the conductivity of the composite material increased to 2.0×10-2 S/m,an increase of 10 orders of magnitude.When the MWCNTs content was 15 wt%,the minimum reflection loss(RLmin)at 14.32 GHz was-20.45 d B with a thickness of 1.5 mm,and the effective absorption bandwidth（EAB）was 3.28 GHz（12.88-16.16 GHz）.（2）NSD-Fe3O4/conductive carbon black（CCB）/NR composites were prepared by mechanical blending method,and the effects of CCB content（weight ratio of CCB addition to natural rubber addition）on the MA properties of the composites was investigated.The particle size of CCB was between 50～100 nm and CCB was uniformly dispersed in the NR matrix in granular form.The electrical conductivity of the composites gradually increased with the increase of CCB content.CCB particles can reflect and scatter electromagnetic waves（EMW）for many times,and the conductive network formed by uniformly dispersed CCB particles has extended the transmission path of EMW,which is conducive to the dissipation of EMW.When the CCB content was 50 wt%,the RLmin of the composites reached-35.30 d B with a thickness of 1.5 mm at 14.16 GHz,and the EAB was 3.84 GHz（12.40～16.24 GHz）.（3）The optimal CCB content was found to be 50 wt%for NSD-Fe3O4/CCB/NR composites.The following research was that MWCNTs were used to replace some CCB to enhance the MA properties of the composites.Therefore,NSD-Fe3O4/CCB/MWCNTs/NR composites were prepared by mechanical blending method,and the MA properties of the composites were tuned by adjusting the content of MWCNTs.The CCB and MWCNTs were uniformly dispersed in the NR matrix.The co-doping of CCB and MWCNTs contributed to the dispersion of both in the NR matrix,resulting in a more complete conductive network.The prepared samples showed the most excellent MA performance when the MWCNTs content was 7.5 wt%.The RLmin of the composites reached-40.78 d B with a thickness of 1.5 mm at 11.36GHz,and the EAB was 2.0 GHz（10.40～12.40 GHz）. |
