Surface Metallization And Microwave Absorption Of Mineral Powder And Organisms

With the rapid development of electronic industry technology,electromagnetic pollution is becoming more and more serious,and with the stealth technology have improving requirements of material absorption.The development of new light weight,bandwidth and absorption of absorbing materials is increasingly important.In this paper,the use of chemical plating method,the technology with its simple,energy saving,environmental protection has been increasingly widespread concern.In order to explore the new high-performance absorbing materials,the nano-metal coating of three different matrix materials（kaolin,carbon nanotubes and E.coli）was used.On the surface of kaolin,the surface of carbon nanotubes was coated with Co-P coating and coating the metal Co coating on the surface of E.coli.The Co-P layer was first coated on the kaolin after the pretreatment,and the obtained coating was characterized by SEM,XRD,EDS and network vector analyzer.Followed by chemical plating of carbon nanotubes,first of which to pretreatment,including de-glue,degreasing,coarsening,followed by activation,sensitization and reduction,The Co-P layer coated carbon nanotubes microscopic Morphology,crystal structure,composition and electromagnetic parameters were characterized.Finally,the surface of the Escherichia coli was electroless plated.After pretreatment,the microstructure,crystal structure,composition and electromagnetic parameters of the pure Co-coated Escherichia coli were characterized by plating in the plating solution.The experimental results show that the Co-P layer is successfully coated on the surface by electroless plating on the surface of kaolin.From the hysteresis loops,the saturation magnetization and coercivity of XK / Co-P are 25.04 A · m2 · kg-1 and 1652.35 A · m-1,respectively.And the electromagnetic properties show that the frequency of 6K or so,where XK / Co-P reflection loss of about-10 dB,showing excellent absorption performance.The main reason may be that the lamellar kaolin adsorbs more Co-P coatings on the agglomerated kaolin surface,exhibiting good absorbing properties.A uniform Co-P coating with a thickness of 2.95 nm was prepared on the surface of CNTs by TEM.At the same time,it was found that the hollow thickness was 4.12 nm and the wall thickness was 3.88 nm.From the relationship between the reflection loss and the frequency.With the increase of the matching thickness,the absorption bandwidth decreases and the absorption peak increases.When the matching thickness is 2.5mm,the reflection loss value of-20 dB or so.In the experiment of pure Co-coated Escherichia coli,it was found that the hydrate hydrazine successfully reduced Co²⁺ in the plating solution by EDS and surface sweep.The coating of pure Co was obtained.From the TEM and the corresponding line sweep results that Co coating thickness is uniform.In the electromagnetic absorption performance,when the matching thickness of 2.0mm,the corresponding reflection loss of-29 dB,for the absorption of electromagnetic waves has been nearly 95% or more.And with the increase of the matching thickness,the absorption peak migrates to the low frequency direction,showing strong absorbing performance.