31results about How to "Absorbing frequency band is wide" patented technology

The invention provides a strontium titanate / polypyrrole nanocomposite fiber with a one-dimensional core-shell structure, and a preparation method thereof. The nanocomposite fiber is composed of a polymer polypyrrole body and a barium strontium titanate nanofiber material, and the barium strontium titanate nanofiber is coated with the polypyrrole to form the core-shell structure. The barium strontium titanate / polypyrrole nanocomposite fiber with the core-shell structure is prepared by an electrospinning process combined gas phase polymerization technology, and the core-shell structure of the barium strontium titanate / polypyrrole nanocomposite fiber is formed by adopting barium strontium titanate as a hard template and polyvinylpyrrolidone as a soft template in the polymerization process. The one-dimensional fibrous wave absorbing material has obvious better wave absorbing ability than a spherical wave absorbing material, the shell thickness of the composite fiber is controllable, and the material of the shell has good electrical conductivity, so the expansion of the wave absorbing band of the composite material is benefited, and the composite nanofiber has the advantages of good one-dimensional morphology, uniform size distribution, good dispersion stability, and simple and easy preparation process.

The invention provides a resin wave-absorbing coating, which comprises: a composite material of resin, graphene and ferric oxide, a dispersant, an anti-sedimentation agent and a solvent. The present invention creatively changes the way of adding graphene materials in the resin wave-absorbing coating. Firstly, the graphene and the hard material in the coating—ferric oxide are compounded to obtain a composite of graphene and ferric oxide. The material is then combined with other ingredients to obtain resinous absorbing coatings. The invention can not only solve the problem of graphene dispersion well, ensure the perfect performance of its excellent performance, solve the disadvantage of uneven mixing of flexible graphene materials in the coating system, but also realize the The uniform dispersion on the surface can better exert its performance; more importantly, it can be used in conjunction with specific components, so that the prepared wave-absorbing coating has thin film, high strength, strong wave-absorbing ability, wide wave-absorbing frequency band, and low cost. low and has broad application prospects.

The invention discloses a microwave sintering method for a SiC ceramic roller. The microwave sintering method comprises the following steps: 1) putting a green SiC ceramic roller body in an insulation apparatus and then placing the green SiC ceramic roller body and the insulation apparatus into a microwave resonant cavity together; and 2) starting a microwave source, adjusting microwave input frequency, carrying out slow heating until humidity elimination and smoke evacuation is finished, then continuously adjusting microwave input frequency, carrying out rapid heating until reflection power is stable, carrying out heating at a heating speed of 20 to 30 DEG C / min to a sintering temperature, maintaining the temperature for 5 to 15 min, then adjusting microwave input frequency and carrying out cooling to room temperature so as to obtain the SiC ceramic roller. The microwave sintering method for the SiC ceramic roller realizes rapid sintering of the SiC ceramic roller, substantially improves uniformity and stability of the performances of a sintered material, effectively avoids the phenomenon of local surface warping of a roller at a fire hole frequently occurred during conventional sintering, improves sintering yield of the SiC ceramic roller and has the advantages of short sintering time, conservation of considerable electric energy and suitability for industrial rapid production.