▎ 摘　　要

NOVELTY - Nitrogen-doped graphene nickel ferrite composite wave absorbing material comprises nitrogen-doped reduced graphene oxide loaded hexagonal nano-nickel ferrite. USE - The nitrogen-doped graphene nickel ferrite composite wave absorbing material is useful in electromagnetic wave absorption and electromagnetic shielding field (claimed). ADVANTAGE - The composite material: has strong electromagnetic wave absorption ability, absorption frequency bandwidth, thin matching thickness and has simple one-step hydrothermal process; ensues double absorption peaks at low frequency (36 GHz) and high frequency (1218 GHz); can changes nitrogen doping amount of graphene in composite material by controlling added volume of hydrazine hydrate; and ensures effective attenuation of electromagnetic waves by composite materials in different wavebands by changing matching thickness. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing nitrogen-doped graphene nickel ferrite composite wave absorbing material, comprising (1) adding deionized water and graphene oxide into container, stirring and ultrasonicating to obtain aqueous dispersion of graphene oxide, (2) adding ferric nitrate nonahydrate and nickel nitrate hexahydrate to the step (1) dispersion, stirring for 5-15 minutes to completely dissolve to form uniform and transparent dispersion, then adding sodium acetate, and stirring for 10-20 minutes to completely dissolve, (3) adding polyethylene glycol to the step (2) solution, and stirring to dissolve in a water bath at 45-55 degrees C, (4) adding hydrazine hydrate to the step (3) solution, mixing uniformly, and adding ammonia while stirring to adjust pH of the mixture to 11, (5) adding the step (4) mixture to a reactor for reaction, cooling to room temperature after the reaction, centrifuging, and washing until the pH of the product is neutral, and (6) pre-freezing the step (5) product for 10-14 hours, and then freeze-drying for 22-26 hours to obtain final product.