Oriented flaky carbonyl iron and MoS 2 /polyurethane composite with improved microwave absorption at thin thickness by s

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Oriented flaky carbonyl iron and MoS2/polyurethane composite with improved microwave absorption at thin thickness by shear force Ying Zhai1,2,* 1 2

, Dongmei Zhu1, Xingcui Ruan2, and Fa Luo1

State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, Shaanxi, China Shaanxi Huaqin Technology Industry Led, Xi’an 710076, Shaanxi, China

Received: 30 June 2020

ABSTRACT

Accepted: 30 October 2020

Oriented flaky carbonyl iron and MoS2/polyurethane (FCI & MoS2/PU) composite with wide absorption bandwidth at thin thickness was successfully prepared by shear force. The morphology, electromagnetic, and microwave absorption properties in the frequency of 2.6–18 GHz of the composites were investigated. It was observed that the flaky FCI and MoS2 particles became orienting along the tape-casting direction under shear force and parallel to each other. Compared with the un-oriented FCI & MoS2/PU composite, the higher complex permittivity and permeability were obtained after oriented, which was superior in achieving improved microwave absorption performance at thin thickness. Wider absorption bandwidths of reflection loss (RL) values below - 5 dB were obtained at the thin thicknesses of 0.5–1.2 mm for the oriented FCI & MoS2/PU composite. It suggests that the orientation by shear force is a promising approach for the preparation of materials with good microwave absorption property at thin thickness.

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Springer Science+Business

Media, LLC, part of Springer Nature 2020

1 Introduction Electromagnetic microwave absorbing materials (MAMs) based on magnetic absorbents including ferrite and/or magnetic metal have been widely investigated in the past decade because of their high complex permeability [1–5]. Compared with nonmagnetic materials, magnetic MAMs have an advantage in microwave attenuation due to simultaneously generating two typical kinds of microwave energy dissipation mechanisms, dielectric loss, and

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https://doi.org/10.1007/s10854-020-04801-w

magnetic loss, under an external electromagnetic microwave [6, 7]. It is widely acknowledged that the absorbing property of MAMs is dominantly depended on the intrinsic characterization of absorbents [8]. It is worth noting that magnetic MAMs filled with mixed-type or hybrid-type absorbents possess improved microwave absorption properties at thin thickness in contrast with the ones filled with singletype magnetic absorbents [8–13]. It is due to the synergistic effect of different absorbents, which results in appropriate complex permittivity and

J Mater Sci: Mater Electron

permeability as well as good impedance matching at thin thickness in gigahertz frequency range. Among the various magnetic materials filled with multicomponent absorbents, the ones which include anisotropic flaky carbonyl iron (FCI) absorbent present outstanding microwave absorbing properties owing to its prominent larger saturation magnetization, complex permeability, and higher Snoke’s limit [14], such as c