Nickel Fiber Silicone-Matrix Composites as Resilient Electrical Conductors

1991 ◽  
Vol 113 (4) ◽  
pp. 417-420 ◽  
Author(s):  
Mingguang Zhu ◽  
D. D. L. Chung
Keyword(s):  
Electrical Resistivity ◽  
Electromagnetic Interference ◽  
Coefficient Of Thermal Expansion ◽  
Electrical Contacts ◽  
Matrix Composites ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Electrically Conducting ◽  
Emi Shielding Effectiveness ◽  
Silicone Matrix

Short nickel fiber silicone-matrix composites containing 3–12 vol. percent fibers were fabricated by the impregnation of silicone into a nickel fiber perform. The composites exhibited volume electrical resistivity ranging from 4.5 × 10−4 to 2.8 × 10−3 ohm.cm, contact electrical resistivity (with copper at a pressure > 0.1 MPa) ranging from 0.0090 to 0.0155 ohm.cm2, permanent set one percent after compression to a stress of 0.4 MPa and a strain up to 13.5 percent for 7 days, and electromagnetic interference (EMI) shielding effectiveness > 50 dB at 1.0–2.0 GHz. The volume and contact resistivities were essentially not affected after heating in air at 130–150°C for 7 days. The coefficient of thermal expansion was 27.5 × 10−6 °C−1 for a composite containing 8.2 vol. percent nickel fibers. These resilient electrically conducting composites are useful for electrical contacts and for gaskets for EMI shielding.

0.4 μm Diameter Nickel-Filament Silicone-Matrix Resilient Composites for Electromagnetic Interference Shielding

1997 ◽  
Vol 119 (4) ◽  
pp. 236-238 ◽  
Author(s):  
Xiaoping Shui ◽  
D. D. L. Chung
Keyword(s):  
Electromagnetic Interference ◽  
Small Diameter ◽  
Matrix Composites ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Electromagnetic Interference Shielding ◽  
Volume Percent ◽  
Emi Shielding Effectiveness ◽  
Percent Nickel ◽  
Silicone Matrix

Resilient silicone-matrix composites containing 7–13 volume percent nickel filaments (0.4 μm diameter) exhibited 74–93 dB electromagnetic interference (EMI) shielding effectiveness at 1–2 GHz and 1 × 10−1 – 2 × 10−2 Ω cm DC volume electrical resistivity. The high shielding effectiveness is due to the small diameter of the nickel filaments. The composites are useful for EMI shielding gaskets and cable jackets.

Study of Mechanical Properties and EMI Shielding Behaviour of Al6061 Hybrid Metal Matrix Composites

2021 ◽  
pp. 894-911
Author(s):  
Ch Hima Gireesh ◽  
Koona Ramji ◽  
K.G Durga Prasad ◽  
Budumuru Srinu
Keyword(s):  
Mechanical Properties ◽  
Metal Matrix Composites ◽  
Electromagnetic Interference ◽  
Metal Matrix ◽  
Matrix Composites ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Emi Shielding Effectiveness ◽  
Hybrid Metal Matrix Composites ◽  
Strength And Stiffness

In the present technological environment, the aerospace industry needs cutting-edge materials not only to meet the requirements such as lower weight and higher values of strength and stiffness, but also to protect against electromagnetic interference. In this article, an attempt has been made to prepare Al6061 hybrid metal matrix composites reinforced with varying percentages of SiC, Al2O3, and fly ash particulates through a stir-casting route. As per ASTM standards, various tests have been conducted to know the density, tensile strength, yield strength, and hardness. Simultaneously, all the prepared composites are tested for electromagnetic interference (EMI) shielding effectiveness (SE) under the X band frequency with the help of a vector network analyzer. In order to identify the composite possessing good mechanical properties, as well as shielding effectiveness, a TOPSIS methodology has been employed in this work. The present study reveals that the proposed hybrid composite contains 5% of each reinforcement material which shows better mechanical properties as well as good shielding effectiveness.

scholarly journals A Novel Processing for CNT-Reinforced Mg-Matrix Laminated Composites to Enhance the Electromagnetic Shielding Property

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1030 ◽  
Author(s):  
Wanshun Zhang ◽  
Hongyang Zhao ◽  
Xiaodong Hu ◽  
Dongying Ju
Keyword(s):  
Electrophoretic Deposition ◽  
Electromagnetic Interference ◽  
Deposition Time ◽  
Laminated Composites ◽  
Electromagnetic Shielding ◽  
Matrix Composites ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Electromagnetic Plane Wave ◽  
Emi Shielding Effectiveness

The microstructure, electrical conductivity, and electromagnetic interference (EMI) shielding effectiveness (SE) of CNTs/Mg Matrix composites prepared by accumulative roll bonding (ARB) were systematically investigated to understand the effects of CNTs on the electromagnetic interference shielding effectiveness property of magnesium. A model based on the shielding of the electromagnetic plane wave was used to theoretically discuss the EMI shielding mechanisms of ARB-processed composites. The experimental results indicated that the methods were feasible to prepare laminated composites. The SE of the material increased gradually with the increase of electrophoretic deposition time. When the electrophoretic deposition time reached 8 min, the value of SE remained 87–95 dB in the frequency range of 8.2–12.4 GHz. The increase in SE was mainly attributed to the improvement in the reflection and multiple reflection losses of incident electromagnetic wave due to the increased amounts of CNTs and interfaces. The methods provided an efficient strategy to produce laminated metal matrix composites with high electromagnetic shielding properties.

scholarly journals Ultrathin, Lightweight, and Flexible CNT Buckypaper Enhanced Using MXenes for Electromagnetic Interference Shielding

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Rongliang Yang ◽  
Xuchun Gui ◽  
Li Yao ◽  
Qingmei Hu ◽  
Leilei Yang ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
High Performance ◽  
Electronic Devices ◽  
Deposition Process ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Emi Shielding Effectiveness ◽  
X Band ◽  
Wearable Electronic Devices ◽  
Emi Se

AbstractLightweight, flexibility, and low thickness are urgent requirements for next-generation high-performance electromagnetic interference (EMI) shielding materials for catering to the demand for smart and wearable electronic devices. Although several efforts have focused on constructing porous and flexible conductive films or aerogels, few studies have achieved a balance in terms of density, thickness, flexibility, and EMI shielding effectiveness (SE). Herein, an ultrathin, lightweight, and flexible carbon nanotube (CNT) buckypaper enhanced using MXenes (Ti3C2Tx) for high-performance EMI shielding is synthesized through a facile electrophoretic deposition process. The obtained Ti3C2Tx@CNT hybrid buckypaper exhibits an outstanding EMI SE of 60.5 dB in the X-band at 100 μm. The hybrid buckypaper with an MXene content of 49.4 wt% exhibits an EMI SE of 50.4 dB in the X-band with a thickness of only 15 μm, which is 105% higher than that of pristine CNT buckypaper. Furthermore, an average specific SE value of 5.7 × 104 dB cm2 g−1 is exhibited in the 5-μm hybrid buckypaper. Thus, this assembly process proves promising for the construction of ultrathin, flexible, and high-performance EMI shielding films for application in electronic devices and wireless communications.

scholarly journals Electromagnetic Interference Shielding Performance Enhancement of Stretchable Transparent Conducting Silver Nanowire Networks with Graphene Encapsulation

2021 ◽  
Author(s):  
Siyi Yan ◽  
Peng Li ◽  
Zhongshi Ju ◽  
He Chen ◽  
Jiangang Ma
Keyword(s):  
Electromagnetic Interference ◽  
Performance Enhancement ◽  
Mechanical Stability ◽  
Silver Nanowire ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Dielectric Polarization ◽  
Emi Shielding Effectiveness ◽  
Graphene Films ◽  
Transparent Conducting

Abstract Silver nanowire (AgNW) networks are promising transparent conducting materials for electromagnetic interference (EMI) shielding and diverse optoelectronic devices. However, the poor contact between adjacent AgNWs leads to low electrical conductivity and weak mechanical stability of AgNW networks, which are limiting the practical application of these electronics. Here we report an efficient strategy to improve the overall performance of AgNW networks, in which the AgNW networks are sandwiched between two layers of graphene films. The graphene films improve the contact of overlapped AgNWs and bridge the discrete AgNWs, and thus increase the conductivity of graphene/AgNWs/graphene (GAG) films. Microwave permittivity measurements together with mechanism analyses reveal that the graphene films can enhance the EMI shielding effectiveness of AgNW networks through offering extra conduction loss, multiple dielectric polarization centers and multi-reflection processes. As a result, the GAG film with an average transmittance of 88% exhibits a sheet resistance lower than 15 Ω sq− 1 and an EMI shielding effectiveness of 31 dB (in the frequency range of 8.2‒12.4 GHz) after repeated stretching and release at a strain of 40%. Such a total performance is superior to that of most of as-reported transparent conductors. The GAG films therefore show application potential in the age of Internet of Things that electromagnetic radiation pollutions are everywhere.

Flexible, conductive, porous, fibrillar polymer–gold nanocomposites with enhanced electromagnetic interference shielding and mechanical properties

2017 ◽  
Vol 5 (5) ◽  
pp. 1095-1105 ◽  
Author(s):  
Jun Li ◽  
Hu Liu ◽  
Jiang Guo ◽  
Zhen Hu ◽  
Zhijiang Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Gold Nanoparticles ◽  
Self Assembly ◽  
Electromagnetic Interference ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Electromagnetic Interference Shielding ◽  
Emi Shielding Effectiveness ◽  
Conductive Nanocomposites ◽  
Gold Nanocomposites

Flexible lightweight conductive nanocomposites prepared by self-assembly of gold nanoparticles on charged polymer nanofibers show enhanced EMI shielding effectiveness and mechanical properties.

EMI Shielding Properties of Polymer Blend with the Inclusion of Graphene Nano Platelets

2021 ◽  
Vol 875 ◽  
pp. 160-167
Author(s):  
Muhammad Fayzan Shakir ◽  
Asra Tariq
Keyword(s):  
Electromagnetic Interference ◽  
Coaxial Cable ◽  
Network Analyzer ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Electrically Conductive ◽  
Emi Shielding Effectiveness ◽  
Increasing Trend ◽  
Shielding Properties ◽  
Basic Prediction

Polymer nano composites based on poly vinyl chloride matrix were fabricated using polyaniline (PANI) and graphene nano platelets (GNP) as electrically conductive nano filler for the application of electromagnetic interference (EMI) shielding. DC conductivity was first evaluated by using cyclic voltammetry and found an increasing trend of electrical conductivity as PANI and GNP was added in PVC matrix that confirms the formation of electrically conductive network structure. Dielectric properties like dielectric constant, dielectric loss and AC conductivity were evaluated in frequency range of 100 Hz to 3 MHz that gives basic prediction for EMI shielding effectiveness. Vector Network Analyzer (VNA) was used to assess EMI shielding properties using coaxial cable method in 11GHz to 20GHz range and it was found that a maximum of 29 dB shielding was archived with the incorporation of 15 wt% of PANI in PVC. This value increased to 56 dB as 5 wt% GNP added in PVC/PANI 15 wt% blend. Interaction of matrix with filler, nature of filler and dispersion of filler in matrix are the key parameters for achieving high shielding effectiveness.

CNT@PDMS/NW composite materials with superior electromagnetic shielding

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Zi-Jing Zhou ◽  
Zhen-Xing Wang ◽  
Xiao-shuai Han ◽  
Jun-Wen Pu
Keyword(s):  
Electromagnetic Interference ◽  
Cellulose Nanofibers ◽  
Original Structure ◽  
Impregnation Method ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Band Frequency ◽  
Conductive Composites ◽  
Emi Shielding Effectiveness ◽  
Xrd Patterns

Abstract Lightweight materials with high electrical conductivity and hydrophobic mechanical properties are ideal materials for electromagnetic interference (EMI) shielding. Herein, the conductive composites with great EMI shielding effectiveness (SE) were successfully obtained by introducing multi-walled carbon nanotube (CNT) and polydimethylsiloxane (PDMS) based on the original structure of natural wood (NW). CNT@PDMS/NW composites were prepared via vacuum-pulse impregnation method and characterized by Fourier transform infrared (FTIR), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) patterns, hydrophobicity analysis, and EMI shielding performance. As demonstrated, CNT nanosheets were successfully inserted into wood matrices, and hydrogen bonding between CNT nanosheets and cellulose nanofibers induced the fabrication of CNT@PDMS/NW composites. CNT@PDMS/NW composites exhibited excellent EMI SE values of 25.2 dB at the X-band frequency.

Freestanding Fe3O4 / Ti3C2Tx MXene / polyurethane composite film with efficient electromagnetic shielding and ultra-stretchable performance

2022 ◽  
Author(s):  
Yongqin Hu ◽  
Chen Hou ◽  
Yuxia Shi ◽  
Jiamei Wu ◽  
Da Yang ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
Tensile Elongation ◽  
Energy Conversion Efficiency ◽  
High Energy ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Emi Shielding Effectiveness ◽  
Polyurethane Composite ◽  
Human Reproductive ◽  
Interfacial Scattering

Abstract Electromagnetic pollution seriously affects the human reproductive system, cardiovascular system, people’s visual system, and so on. A novel versatile stretchable and biocompatible electromagnetic interference (EMI) shielding film has been developed, which could effectively attenuate electromagnetic radiation. The EMI shielding film was fabricated with a convenient solution casting and steam annealing with 2D MXene, iron oxide nanoparticles, and soluble polyurethane. The EMI shielding effectiveness is about 30.63 dB at 8.2 GHz, based on its discretized interfacial scattering and high energy conversion efficiency. Meanwhile, the excellent tensile elongation is 30.5%, because of the sliding migration and gradient structure of the nanomaterials doped in a polymer matrix. In addition, the film also demonstrated wonderful biocompatibility and did not cause erythema and discomfort even after being attached to the arm skin over 12 hours, which shows the great potential for attenuation of electromagnetic irradiation and protection of human health.

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