▎ 摘　　要

NOVELTY - Preparing cobalt-nickel alloy particle/reduced graphene composite material with sandwich structure comprises simultaneously changing the pH regulator, type of agent, and adjusting the precursor concentration to change the load of cobalt-nickel alloy particle size, the specific steps (1) firstly, ultrasonically dispersing 40 plus minus 3 mg graphene oxide in 20 plus minus 3 ml ethylene glycol, the ultrasonic time is 30 plus minus 5 minutes, adding 0.05 plus minus 0.03 g cobalt acetate, stirring and dissolving, and then adding 0.2 plus minus 0.08 g nickel acetate and stirring to dissolve; (2) adding ethylene glycol solution in which 0.12 plus minus 0.05 g citric acid dissolving in first solution; the speed of dropping the liquid is 8-15 seconds/drop, and sonicating; (3) transferring the above reaction solution to the reaction vessel, heating, and reacting; cooling in a hydrothermal kettle, washing with deionized water and absolute ethanol and centrifuging and separating; and (4) placing the composite in deionized water, and drying. USE - The composite material is useful in the field of microwave absorption (claimed). ADVANTAGE - The composite material: exhibits excellent loss property in field of microwave absorption, especially cobalt-nickel alloy particles have an average size in the composite dispersion of the 0.8 mu m, the maximum microwave loss can reach -54.4dB (secondary microwave absorbing peak is -45.4dB), bandwidth upto 4 GHz, as the wave-absorbing material of microwave absorption, and has wide use prospect. DETAILED DESCRIPTION - Preparing cobalt-nickel alloy particle/reduced graphene composite material with sandwich structure comprises simultaneously changing the pH regulator, type of agent, and adjusting the precursor concentration to change the load of cobalt-nickel alloy particle size, the specific steps (1) firstly, ultrasonically dispersing 40 plus minus 3 mg graphene oxide in 20 plus minus 3 ml ethylene glycol, the ultrasonic time is 30 plus minus 5 minutes, adding 0.05 plus minus 0.03 g cobalt acetate, stirring and dissolving, and then adding 0.2 plus minus 0.08 g nickel acetate and stirring to dissolve to obtain first solution; (2) adding 20 plus minus 3 ml ethylene glycol solution in which 0.12 plus minus 0.05 g citric acid dissolving in first solution; the speed of dropping the liquid is 8-15 seconds/drop, and then sonicating the above solution for 40 plus minus 5 minutes to obtain the reaction solution; (3) transferring the above reaction solution to the reaction vessel, heating to 210 plus minus 10 degrees C, and reacting for 12-15 hours; then cooling in a hydrothermal kettle, washing for many times with deionized water and absolute ethanol and centrifuging and separating to obtain the composite viscous cobalt/nickel-reduced graphene; and (4) placing the resulting composite in 20 plus minus 10 ml deionized water, and drying by a freeze dryer for 24 plus minus 1 hour to finally obtain a cobalt-nickel alloy particle/reduced graphene composite having sandwich structure. An INDEPENDENT CLAIM is also included for cobalt-nickel alloy particle/reduced graphene composite material with sandwich structure is prepared by the above mentioned method.