Ultra-wide bandwidth with enhanced microwave absorption of electroless Ni-P coated tetrapod-shaped ZnO nano- and microstructures.
Ultra-wide bandwidth with enhanced microwave absorption of electroless Ni-P coated tetrapod-shaped ZnO nano- and microstructures.
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DOI：
10.1039/c5cp03488d
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发表时间：
2015-08
期刊：
影响因子：
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通讯作者：
M. Najim;Gaurav Modi;Y. Mishra;R. Adelung;Dharmendra Singh;V. Agarwala
中科院分区：
文献类型：
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作者：
M. Najim;Gaurav Modi;Y. Mishra;R. Adelung;Dharmendra Singh;V. Agarwala
一种可行的轻量化吸收体是当前隐身技术以及微波吸收的需要。已经开发了几种微波吸收器，但制造一种吸收器仍然是一个挑战，这种吸收器可以促进宽带微波吸收或覆盖2-18 GHz频率范围的最大部分，这是雷达和其他应用的常用范围。因此，迫切需要开发一种宽带吸收器，既能在2-18 GHz的大部分频率范围内提供微波吸收，同时又轻便，并且可以通过经济有效的合成方法批量制造。本文尝试用镍磷包覆的四足形ZnO （Ni-P coated T-ZnO）来设计具有增强微波吸收响应的超宽带吸收体。在Ni- p包覆的T-ZnO吸收体中，ZnO作为良好的介电组分，而Ni作为磁性组分，获得了具有良好吸收性能的微波吸收复合材料。采用简单、可扩展的两步法合成了Ni-P包覆ZnO纳米微结构。首先，采用火焰传递合成（FTS）方法在单步工艺中生长出四足形ZnO （T-ZnO）结构，然后采用化学涂层技术在其表面涂覆Ni-P。采用扫描电子显微镜（SEM）、透射电子显微镜（TEM）和x射线衍射（XRD）技术对其形貌、结晶度和存在相进行了详细研究。测量了制备的T-ZnO和Ni-P包覆的T-ZnO在4-14 GHz频率范围内的复介电常数和磁导率，并用同轴透射-反射法计算了它们的微波吸收特性。在4.0-14.0 GHz频率范围内，带宽为10.0 GHz （RL < -10 dB）的Ni-P涂层T-ZnO样品，在~ 8.99 GHz频率下，涂层厚度为3.4 mm，获得了最强反射损耗（RL）峰值-36.41 dB。
A viable lightweight absorber is the current need for stealth technology as well as microwave absorption. Several microwave absorbers have been developed, but it is still a challenge to fabricate an absorber that facilitates microwave absorption in broad bandwidth or covers the maximum portion of the frequency range 2-18 GHz, the commonly used range for radar and other applications. Therefore, it is highly required to develop a wide bandwidth absorber that can provide microwave absorption in the most part of the frequency range 2-18 GHz while simultaneously being lightweight and can be fabricated in desired bulk quantities by the cost-effective synthesis methods. In this paper, an attempt has been made to design an ultra-wide bandwidth absorber with enhanced microwave absorption response by using nickel-phosphorus coated tetrapod-shaped ZnO (Ni-P coated T-ZnO). In the Ni-P coated T-ZnO absorber, ZnO acts as a good dielectric contributor, while Ni as a magnetic constituent to obtain a microwave absorbing composite material, which has favorable absorption properties. Ni-P coated ZnO nano-microstructures are synthesized by a simple and scalable two-step process. First, tetrapod-shaped ZnO (T-ZnO) structures have been grown by the flame transport synthesis (FTS) approach in a single step process and then they have been coated with Ni-P by an electroless coating technique. Their morphology, degree of crystallinity and existing phases were studied in detail by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) techniques. The complex permittivity and permeability of the "as-fabricated" T-ZnO and Ni-P coated T-ZnO have been measured in the frequency range of 4-14 GHz and their microwave absorption properties are computed using the coaxial transmission-reflection method. The strongest reflection loss (RL) peak value of -36.41 dB has been obtained at a frequency of ∼8.99 GHz with coating thickness of 3.4 mm for the Ni-P coated T-ZnO sample with a broad bandwidth of 10.0 GHz (RL < -10 dB) in the frequency range of 4.0-14.0 GHz.