Microwave Loss Mechanism And Performance Optimization Of MOFs Derived Co/Ni@CNTs Nanocomposites

Nowadays,information and communication technology has occupied an important position in all aspects of people's life and work,and has produced earth shaking changes in people's life.However,it is inevitable to bring a large number of electromagnetic waves in the environment,which pose severe challenges to human health and the stability of electronic equipment.Microwave absorbing materials can greatly reduce the electromagnetic wave in the environment and reduce the harm to people's production and life.They have excellent performance in the fields of electronic communication,integrated circuit and stealth technology,and have important research value.Metal organic frame materials(MOFs)are crystal polymers with rich microporous structure.MOFs can provide rich carbon sources and can be used as precursor of calcined carbon based composites.During pyrolysis,the material components can be easily changed into metal,metal oxide or its hybrid.The CNTs derived from MOFs can not only form different layers,but also reduce weight,which is widely welcomed by researchers.Two MOFs derived materials were successfully prepared by carbon thermal reduction method.The electromagnetic loss mechanism and absorbing property of MOFs were analyzed and studied.The specific research contents are as follows:(1)CNTs hollow microspheres Ni@CNTs-BTC compound material were synthesized by annealing the precursor Ni-BTC hollow microspheres use carbon thermal reduction.The influence of the micro morphology on the absorption effect and the effect of Ni and CNTs on the magnetic dielectric loss mechanism are analyzed.The electromagnetic parameters of the system are measured by network analyzer and the reflection loss is calculated.The results show that,Ni@CNTs-BTC composite has excellent absorbing effect.When 30 wt%of the load is filled,it reaches the strongest reflection loss of-57.0 dB at 12.1 GHz,the effective bandwidth coverage is 10.4-14 GHz,and the thickness is only 2.4 mm.When the sample thickness is 2 mm,The widest frequency range below10 dB is up to 5 GHz(12.7-17.7 GHz).(2)The synthesis of the composite by carbon thermal reduction ZIF67@ZIF-8@GO The precursor was annealed and obtained Co@CNTs@rGO compound material.The principle of design and synthesis and the mechanism of electromagnetic loss are analyzed.The microwave absorption effect of reducing graphene oxide is studied.When 15 wt%of the load is filled,it reaches the strongest reflection loss of-62.3 dB at 14.5 GHz,and the effective bandwidth coverage is 12.6-17.4 GHz(4.8 GHz),and the thickness is only 1.7 mm.The composite has many layers,which can not only increase the polarization of the interface,but also greatly reduce the weight of the material.In conclusion,the magnetic medium@CNTs composite derived from MOFs can effectively utilize the coordination of magnetic dielectric loss to obtain good impedance matching characteristics.As a light and efficient absorbing material,it has great potential in the future practical application.By using electromagnetic simulation software to model and simulate the two kinds of absorbing coatings,the excellent microwave absorption effect is further verified.