Preparation and Electromagnetic Shielding Effectiveness of a New Kind of Electromagnetic Shielding Composite Coatings

2013 ◽  
Vol 395-396 ◽  
pp. 37-40 ◽  
Author(s):  
Deng Gao Guan ◽  
Yao Sun ◽  
Guan Li Xu ◽  
Chuan Min Sun ◽  
Hua Wei Li ◽  
...  

A new kind of the electromagnetic shielding composite coatings with high performance was prepared using the Ni-Cu-coated glass fibers and nickel powders as fillers and using epoxy resin as binder. The effects of the fibers on the conductivity and electromagnetic shielding effectiveness of the coatings were studied. The study results show as follows: 1) when the optimum ratio of the fillers to epoxy resin is 4:1, the coatings containing 6 wt% the Ni-Cu-coated glass fibers has best conductivity and electromagnetic shielding effectiveness; when the coating layer thickness is 300 μm, the shielding effectiveness of the coatings is up to 43.71-52.31 dB and increased an average of 13.94 dB compared with the nickel powders/ epoxy resin electromagnetic shielding coatings in the frequency range of 0.3-1000 MHz. This offers a new idea to enhance the added value of the glass fibers and the prevention of electromagnetic environmental pollution.

2011 ◽  
Vol 189-193 ◽  
pp. 400-403
Author(s):  
Deng Gao Guan ◽  
Chuan Min Sun ◽  
Jin Hui Lin ◽  
Yao Sun ◽  
Guan Li Xu ◽  
...  

A new kind of Ni-Cu-coated calcium-magnesium silicate whiskers was prepared by electroless plating and characterized by EDS, SEM and XRD. And the preparation and shielding performance of a new kind of Ni-Cu-coated calcium-magnesium silicate whisker/nickel powder/epoxy resin electromagnetic shielding coatings were explained. The study results show the Ni-Cu-coated whisker with micro-sized spinal structure contains 12.4 wt% Ni and 1.35 wt% Cu. When the coating layer thickness is 300 μm, the shielding effectiveness of the coatings containing 4 wt% Ni-Cu-coated calcium-magnesium silicate whisker is up to 39.24-48.52 dB and increased an average of 10.38 dB compared with the nickel powder/epoxy resin electromagnetic shielding coatings in the frequency range of 0.3-1000 MHz. This offers a new idea to raise the levels of the comprehensive utilization of mineral resources and the prevention of electromagnetic environmental pollution.


Coatings ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 740
Author(s):  
Yanfei Pan ◽  
Dingwen Yin ◽  
Xiaofang Yu ◽  
Nanyi Hao ◽  
Jintian Huang

The lightweight multilayer-structured electromagnetic interference shielding composite coatings with controllable electromagnetic gradient on wood surface were prepared via a simple multiple electroless copper–nickel (Cu–Ni) approach. The surface morphology, conductivity, hydrophobicity property and electromagnetic shielding effectiveness of the composite coatings were investigated. The surface roughness and conductivity of the composite coatings were enhanced with the increase in the number of depositions. The surface morphology demonstrated that the roughness was decreased with the process of multiple electroless. The coatings were compact and homogeneous as the deposition run was three. Here, the Sa (Sa illustrated Surface Roughness) value of coatings was 4.497 μm. The ideal conductivity of composite coatings can be obtained as the number of depositions was four. Electromagnetic shielding effectiveness reached average 90.69 dB in the frequency range from 300 kHz to 2.0 GHz. This study provides a new pathway for fabricating lightweight multilayer-structured electromagnetic interference shielding with controllable electromagnetic gradient and hydrophobic composite coatings-based wood.


2020 ◽  
Vol 4 (1) ◽  
pp. 28
Author(s):  
Konstantinos Tserpes ◽  
Vasileios Tzatzadakis ◽  
Jens Bachmann

In this paper, the electrical conductivity and electromagnetic shielding effectiveness of two bio-composites are studied by experimental testing and numerical models. Two monolithic composites with partly bio-based content were manufactured. The first bio-composite is made of a carbon fiber fabric prepreg and a partly bio-based (rosin) epoxy resin (CF/Rosin). The second bio-composite is a combination of prepregs of carbon fiber fabric/epoxy resin and flax fiber fabric/epoxy resin (CF-Flax/Epoxy). A single line infusion process was used prior to the curing step in the autoclave. Both variants are exemplary for the possibility of introducing bio-based materials in high performance CFRP. In-plane and out-of-plane electrical conductivity tests were conducted according to Airbus standards AITM2 0064 and AITM2 0065, respectively. Electromagnetic shielding effectiveness tests were conducted based on the standard ASTM D 4935-10. Materials were prepared at the German Aerospace Center (DLR), while characterization tests were conducted at the University of Patras. In addition to the tests, numerical models of representative volume elements were developed, using the DIGIMAT software, to predict the electrical conductivity of the two bio-composites. The preliminary numerical results show a good agreement with the experimental results.


2011 ◽  
Vol 148-149 ◽  
pp. 963-967
Author(s):  
Peng Jin ◽  
Shi Yun Dong ◽  
Bin Shi Xu ◽  
Zhan Yong Song

Nickel coating was prepared on surface of Epoxy Resin plate by electroless plating process. Surface and section morphologies of the coatings were observed by scanning electron microscopy (SEM) and metallographic optic microscopy. Electromagnetic shielding effectiveness was evaluated via flanged coaxial electromagnetic shielding effectiveness tester. The results showed that the surface of the nickel coating prepared by electroless plating process was smooth, and its structure was fine and compact. The electroless deposition rate of the nickel coating reached at 12μm/h. In the frequency range of 300 kHz to 100MHz the electromagnetic shielding effectiveness of the nickel coating was above 60dB, and in the frequency range of 100MHz to 1.5GHz the electromagnetic shielding effectiveness of the nickel coating was above 44dB.


2011 ◽  
Vol 217-218 ◽  
pp. 321-325 ◽  
Author(s):  
Deng Gao Guan ◽  
Chuan Min Sun ◽  
Jin Hui Lin ◽  
Yao Sun ◽  
Guan Li Xu ◽  
...  

A new kind of the micron-sized flaky silver-coated copper powder was prepared by electroless silver plating in this paper. Its plating structures were characterized by XRD, SEM and EDS. And a new kind of the electromagnetic shielding composite coatings containing 60 wt% the micron-sized flaky silver-coated copper powders and 40 wt% epoxy resin was prepared. Its electromagnetic shielding properties were analyzed by coaxial transmission line equipment. The study results show the micron-sized flaky silver-coated copper powders are composed of 91.35 wt% Cu and 8.65 wt% Ag and have high width-thickness ratio and crystal structure characteristics. In the frequency range of 0.3-1000 MHz, the shielding effectiveness of the coatings is up to 70.15-77.46 dB and increased an average of 22.18 dB compared with the coatings containing 60 wt% micron-sized flaky copper powders when the coating layer thickness is 300 μm. It is seen that the electroless silver plating method effectively improves the inoxidizability, conductivity and electromagnetic shielding properties of copper powders.


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