Microwave absorption properties of Ni/C@SiC composites prepared by precursor impregnation and pyrolysis processes

In the present study, the unique three-dimensional graphene coated nickel (Ni/C) foam reinforced silicon carbide (Ni/C@SiC) composites were first obtained via the precursor impregnation and pyrolysis (PIP) processes. The microstructure images indicated that the SiC fillers were successfully prepared in the skeleton pores of the Ni/C foam. The influence of the PIP cycles on the microwave absorption perfor-mances was researched, and the results indicated that after the primary PIP process, Ni/C@SiC-I possessed the optimal microwave absorbing performance with a minimum reflection loss(RL) of -25.87 dB at 5.28 GHz and 5.00 mm. Besides, the RL values could be below -10.00 dB from 5.88 GHz to 7.74 GHz when the corresponding matching thickness was 3.85 mm. However, the microwave ab-sorption properties of Ni/C@SiC-II and Ni/C@SiC-III were tremendously degraded as the PIP times increased. At last, the electromagnetic parameter, dielectric loss, attenuation constant as well as impedance matching coefficient were further investigated to analyze the absorbing mechanism, which opened a new path for the certain scientific evaluation of the absorbing materials and had extremely important to the defence technology.(c) 2021 China Ordnance Society. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).