Magnetic porous cobalt hollow ball electromagnetic wave absorption material, preparation method and application thereof

Abstract

The invention relates to a magnetic porous cobalt hollow ball electromagnetic wave absorption material, a preparation method and application of the material. The magnetic porous cobalt hollow ball electromagnetic wave absorption material is composed of monodispersed porous hollow balls, wherein the external diameter of each porous hollow ball is 2-6 microns, and the thickness of each ball shell is 100-200nm. The hollow balls are formed by cobalt particles, wherein the diameter of each cobalt particle is 60-200nm, and 10-100nm air voids exist among the cobalt particles. The preparation method includes the steps of using precursors like cobaltous acetate and precipitants like urea, and polyving akohol or polymethyl methacrylate or polyvinylpyrrolidone as surfactants, enabling the surfactants to be dissolved in ethyl alcohol solvents or methanol solvents to obtain cobaltous hydroxides through reaction, and enabling the cobaltous hydroxides and potassium borohydride to be reacted in water or ethanol solutions to obtain the monodispersed porous cobalt hollow balls. The prepared porous cobalt hollow ball material is good in evenness and dispersity, small in density, strong in magnetism and good in electromagnetic wave absorption performance and can be used as the electromagnetic wave absorption material.

Description

technical field [0001] The invention relates to a magnetic porous cobalt hollow sphere electromagnetic wave absorbing material and a preparation method and application thereof, belonging to the technical field of magnetic and electromagnetic wave absorbing materials. Background technique [0002] With the rapid development of radio communication technology and high-frequency circuit equipment, electromagnetic wave absorbing materials, as an effective means of reducing electromagnetic wave interference, can convert electromagnetic waves into other forms of energy and attenuate them. Magnetic loss, dielectric loss, and conductive loss materials can all be used as electromagnetic wave absorbers, and magnetic loss materials have become a current research hotspot, because thinner electromagnetic wave absorbers can be prepared from them. In order to further meet the needs of applications, now Phase research is dedicated to the development of high-frequency, broadband, strong absor...

AI Technical Summary

Problems solved by technology

The main reason for its weak absorption strength is that the flower-like structure of cobalt is composed of solid cobalt particles with a size of 1-5 microns, and the flower-like structure is poorly dispersed and bonds with each other to form larger aggregates

Since metal cobalt is a good conductor of electricity, the eddy current loss of large-sized aggregates in the electromagnetic wave environment is large, which weakens its electromagnetic absorption; (2) The composite material of cobalt nanochain structure and paraffin with a mass fraction of 20% is There is electromagnetic wave absorption in the -18GHz frequency range, but the absorption intensity is weak. When the thickness of the absorbing layer is 3mm, its maximum absorption intensity at 17.5GHz is only -17dB (decibels), see Appl.Phys.Lett.,2009,95 , 163108, mainly due to the formation of a chain structure of cobalt nanoparticles, which makes the dispersion of the material low, and crosslinks each other in the paraffin composite material to form a conductive network, which produces a large eddy current loss in the electromagnetic wave environment and reduces the magnetic permeability. , resulting in weak electromagnetic wave absorption strength of the material

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