title: Morphology-Control Synthesis of a Core-Shell Structured NiCu Alloy with Tunable Electromagnetic-Wave Absorption Capabilities.
abstract: In this work, dendritelike and rodlike NiCu alloys were prepared by a one-pot hydrothermal process at various reaction temperatures (120, 140, and 160 °C). The structure and morphology were analyzed by scanning electron microscopy, energy-dispersive spectrometry, X-ray diffraction, and transmission electron microscopy, which that demonstrate NiCu alloys have core-shell heterostructures with Ni as the shell and Cu as the core. The formation mechanism of the core-shell structures was also discussed. The uniform and perfect dendritelike NiCu alloy obtained at 140 °C shows outstanding electromagnetic-wave absorption properties. The lowest reflection loss (RL) of -31.13 dB was observed at 14.3 GHz, and the effective absorption (below -10 dB, 90% attenuation) bandwidth can be adjusted between 4.4 and 18 GHz with a thin absorber thickness in the range of 1.2-4.0 mm. The outstanding electromagnetic-wave-absorbing properties are ascribed to space-charge polarization arising from the heterogeneous structure of the NiCu alloy, interfacial polarization between the alloy and paraffin, and continuous micronetworks and vibrating microcurrent dissipation originating from the uniform and perfect dendritelike shape of NiCu prepared at 140 °C.
authors.affiliation: †School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, China.
authors.forename: Biao
authors.initials: B
authors.lastname: Zhao
authors.affiliation: †School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, China.
authors.forename: Wanyu
authors.initials: W
authors.lastname: Zhao
authors.affiliation: †School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Shao
authors.affiliation: †School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, China.
authors.forename: Bingbing
authors.initials: B
authors.lastname: Fan
authors.affiliation: †School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, China.|‡Zhengzhou Institute of Aeronautical Industry Management, Zhengzhou 450046, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
keywords: NiCu alloys; core−shell structure; dendrite-like shape; dielectric loss; microwave absorption; rod-like shape