title: Yolk-Shell Ni@SnO2Composites with a Designable Interspace To Improve the Electromagnetic Wave Absorption Properties.
abstract: In this study, yolk-shell Ni@SnO2composites with a designable interspace were successfully prepared by the simple acid etching hydrothermal method. The Ni@void@SnO2composites were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The results indicate that interspaces exist between the Ni cores and SnO2shells. Moreover, the void can be adjusted by controlling the hydrothermal reaction time. The unique yolk-shell Ni@void@SnO2composites show outstanding electromagnetic wave absorption properties. A minimum reflection loss (RLmin) of -50.2 dB was obtained at 17.4 GHz with absorber thickness of 1.5 mm. In addition, considering the absorber thickness, minimal reflection loss, and effective bandwidth, a novel method to judge the effective microwave absorption properties is proposed. On the basis of this method, the best microwave absorption properties were obtained with a 1.7 mm thick absorber layer (RLmin= -29.7 dB, bandwidth of 4.8 GHz). The outstanding electromagnetic wave absorption properties stem from the unique yolk-shell structure. These yolk-shell structures can tune the dielectric properties of the Ni@air@SnO2composite to achieve good impedance matching. Moreover, the designable interspace can induce interfacial polarization, multiple reflections, and microwave plasma.
authors.affiliation: Provincial Key Laboratory of Aviation Materials and Application Technology, Zhengzhou University of Aeronautics , Zhengzhou, Henan 450046, China.|School of Mechatronics Engineering, Zhengzhou University of Aeronautics , Zhengzhou, Henan 450046, China.
authors.forename: Biao
authors.initials: B
authors.lastname: Zhao
authors.affiliation: Provincial Key Laboratory of Aviation Materials and Application Technology, Zhengzhou University of Aeronautics , Zhengzhou, Henan 450046, China.|School of Mechatronics Engineering, Zhengzhou University of Aeronautics , Zhengzhou, Henan 450046, China.
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Guo
authors.affiliation: School of Materials Science and Engineering, Zhengzhou University , Zhengzhou, Henan 450001, China.
authors.forename: Wanyu
authors.initials: W
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Faculty of Land Resource Engineering, Kunming University of Science and Technology , Kunming, Yunnan 650093, China.
authors.forename: Jiushuai
authors.initials: J
authors.lastname: Deng
authors.affiliation: School of Materials Science and Engineering, Zhengzhou University , Zhengzhou, Henan 450001, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Shao
authors.affiliation: School of Materials Science and Engineering, Zhengzhou University , Zhengzhou, Henan 450001, China.
authors.forename: Bingbing
authors.initials: B
authors.lastname: Fan
authors.affiliation: Provincial Key Laboratory of Aviation Materials and Application Technology, Zhengzhou University of Aeronautics , Zhengzhou, Henan 450046, China.|School of Mechatronics Engineering, Zhengzhou University of Aeronautics , Zhengzhou, Henan 450046, China.
authors.forename: Zhongyi
authors.initials: Z
authors.lastname: Bai
authors.affiliation: Provincial Key Laboratory of Aviation Materials and Application Technology, Zhengzhou University of Aeronautics , Zhengzhou, Henan 450046, China.|School of Materials Science and Engineering, Zhengzhou University , Zhengzhou, Henan 450001, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
keywords: Ni@void@SnO2; electromagnetic parameter; interfacial polarization; microwave absorption; multiple reflections; yolk−shell structure