• Corrosion Science and Technology
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• v.9 no.4
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• pp.153-158
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• 2010

Electrical appliances such as audiovisual equipment and personal computers have recently had heat and electromagnetic problems. In order to solve those problems, 'High heat absorbing pre-painted steel sheet (hereinafter referred to as PSS)', 'High electromagnetic shielding PSS' and 'High heat absorbing and high electromagnetic shielding PSS' have been developed. In this paper, the heat characteristics and electromagnetic shielding properties of PSS are investigated by methods that use enclosures and their mechanisms are discussed. It was found that 'High heat absorbing PSS' and 'High heat absorbing and high electromagnetic shielding PSS'could reduce the heat problem. The mechanism of the heat characteristics was presumed for the high heat absorptivity of the back coating inside the enclosure. And it was also found that 'High electromagnetic shielding PSS' and 'High heat absorbing and high electromagnetic shielding PSS' could shield electromagnetic waves well. The mechanism of the electromagnetic shielding properties was considered for the low transfer impedance of the back coating inside the enclosure. 'High heat absorbing PSS' and 'High electromagnetic shielding PSS' have been adopted as materials for electrical appliances and 'High electromagnetic shielding and high heat absorbing PSS' have been tested for that purpose.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1331-1334
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• 2004

The research on electromagnetic shielding has been advanced for military applications as well as for commercial products. Utilizing the reflective properties and absorptive properties of shielding material, the replied signal measured at the rear surface or at the signal source can be minimized. The shielding effect was obtained from materials having special absorptive properties or from structural characteristics such as stacking sequence. Recently researchers studied the electromagnetic properties of nano size particles. In this research {glass fiber}/{epoxy}/{nano particle} composites(GFR-Nano composites), was fabricated using various nano particles, and their properties in electromagnetic shielding were compared. For the visual observation of the nano composite materials, SEM(Scanning Electron Microscope) and TEM(Transmission Electron Microscope) were used. For the measurement of electromagnetic shielding, HP8719ES S-parameter Vector Network Analyser System was used on the frequency range of 8 GHz～12GHz. Among the nano particles, carbon black and Multi-Walled Carbon Nano-Tube (MWCNT) revealed outstanding electromagnetic shielding. Although silver nano particles (flake and powder) were expected to have effective electromagnetic shielding due to their excellent electric conductivities, test showed little shielding effect.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.10 s.175
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• pp.121-128
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• 2005

The research on electromagnetic shielding has been advanced for military applications as well as for commercial products. Utilizing the reflective properties and absorptive properties of shielding material, the replied signal measured at the rear surface or at the signal source can be minimized. The shielding effect was obtained from materials having special absorptive properties and structural characteristics such as stacking sequence. Recently researchers studied the electromagnetic properties of nano size particles. In this research {glass fiber}/{epoxy}/{nano particle} composites(GFR-Nano composites) was fabricated using various nano particles, and their properties in electromagnetic shielding were compared. For the visual observation of the nano composite materials, SEM(Scanning Electron Microscope) and TEM(Transmission Electron Microscope) were used. For the measurement of electromagnetic shielding, HP8719ES S-parameter Vector Network Analyser System was used on the frequency range of 8 GHz${\~}$12GHz. Among the nano particles, carbon black and Multi-Walled Carbon Nano-Tube (MWCNT) revealed outstanding electromagnetic shielding. Although silver nano particles (flake and powder) were expected to have effective electromagnetic shielding due to their excellent electric conductivities, test results showed little shielding characteristics.

• Computers and Concrete
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• v.17 no.2
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• pp.281-294
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• 2016

The increased awareness of electromagnetic wave hazards has prompted studies on electromagnetic shielding using conductive materials in the construction industry. Previous studies have explored the effects of the types of conductive materials and their mix proportions on the electromagnetic shielding performance; however, there has been insufficient research on the effect of the geometry of the conductive materials on the electromagnetic shielding performance. Therefore, in this study, the dependence of the electromagnetic shielding performance on the cross-sectional geometry, diameter and length of fibers was investigated. The results showed that the electromagnetic shielding performance improved when the fiber length increased or the diameter decreased, but the effect of the cross-sectional geometry of the fibers was smaller than the effect of the fiber spacing factor.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.1 s.139
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• pp.149-156
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• 2005

The purpose of this study was to produce the high quality of electromagnetic wave shielding fabrics. In this study, we have produced polyester fabrics by electroless Ag plating. The untreated polyester was etched with $4\%$ NaOH solution added accelerant(Benzyl Dimethyl Dodecyl Ammonium Chloride) then it was catalyzed by $SnCl_2$ solution and activated by $PdCl_2$ solution. Electroless Ag plating was carried out by changing conditions such as temperature. time, weight loss rate of polyester and kind of reducing agents. The electromagnetic wave shielding effectiveness of polyester fabric by electroless Ag plating was measured by RF Impedance Analyzer and element of electromagnetic wave shielding substance was measured using Electron probe micro analyzer. The results were as follows; The plating bath using potassium sodium tartrate by reducing agent was excellent electromagnetic wave shielding effectiveness. Element of electromagnetic wave shielding substance was silver. Electromagnetic wave shielding effectiveness was shown over 64dB at the temperature of $40^{\circ}C$, treating time 30min., weight loss rate $20\%$.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.7
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• pp.71-78
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• 2010

The objective of this research is to investigate the influence of material characteristic and design on to the electromagnetic interference (EMI) shielding characteristics. Basalt glass fiber reinforced composite specimens with stainless fiber conductive filler were manufactured to perform the electromagnetic interference shielding effectiveness(SE) experiments. In order to reflection and absorb the specimen in electromagnetic fields, flanged coaxial transmission line sample holder was fabricated according to ASTM D 4935-89. Electromagnetic shielding effectiveness(EMSE) was measured quantitatively to examine the electromagnetic shielding characteristics of designed specimens. The result of EMI shielding experiments showed that maximum EMSE value of sandwich type specimens with GSG(basalt glass fiber/stainless fiber/basalt glass fiber) and SGS(stainless fiber/basalt glass fiber/stainless fiber) were 65dB and 80dB at a frequency of 1,500MHz, respectively.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.12
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• pp.49-55
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• 2020

In order to improve the electromagnetic shielding rate of Carbon Fiber (CF), it was produced using the nickel nano-powder impregnating method. Using two types of nickel powder having thicknesses of 50 ㎛ and 100 ㎛, and a thermoplastic elastomer resin, a compound containing 10-20% nickel content was mixed and then manufactured through an extruder. The CF coated with the compound was woven and manufactured using a 1-ply specimen. The final nickel content of the specimen was verified using TGA and the distribution of nickel powder on the CF surface was verified using SEM. The metal shows a high shielding rate in the low-frequency band, but the shielding rate decreases at higher-frequency bands. The CF improves at the higher frequency band, and metals reflect electromagnetic waves while carbon absorbs electromagnetic waves. The study of shielding materials, which are stronger and lighter than metal, by using CF lighter than metal and enabling the shielding rate from low-frequency band to high-frequency band, confirmed that the larger the area coated with nickel nano-powder, the better the electromagnetic shielding performance. In particular, CF coated with a thickness of 100 ㎛ has a shielding rate similar to that of copper and can also be used for EV/HEV automotive cables and other applications in the future.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.73-79
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• 2001

In this paper, shielding effectiveness(SE) of the shielding material of electromagnetic(EM) waves was investigated with actual experiments. The materials used in this study were made up of sputtering, film and powder of conductive materials - Cr, Al, Ag and Cu etc. Also, the polyester film was used as a base material. The experiment was carried out by using a shielding evaluator(Shielding box) TR17302 with an ADVANTEST spectrum analyzer, model R3361C. It was found from the experimental results that silver, copper, aluminum and chromium were good candidates as a shielding material against the EM waves with increasing the SE as the composite was laminated. The characteristics of the SE against the EM waves depended on a mode of preparation of specimen. The effects of density of particles on the SE were studied when the sputtering. The SE strongly depended on the electric resistance by density of sputtering and painting particles. SE increased as the density of particles was increasing.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.20-21
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• 2016

In this study, the shielding properties of concrete with conductive materials as shielding material for electromagne- tic pulse(EMP) within 10kHz~18GHz were investigated. The shielding effectiveness of specimens were compared with different entrained materials. The shielding effectiveness were determined according to MIL-STD-188-125-1, IEEE-STD-299 at 28 days of concrete curing. The results of shielding effectiveness did not meet the criteria(80dB) severely.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.8-9
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• 2020

In this study, the electrical conductivity and shielding effect were evaluated according to the type of metal and the thickness of Metal sprayed coating. The metals used for the test are Cu, Cu-Ni and Cu-Zn, and the thicknesses were 100, 200, 500 um. Each metal sprayed coating was evaluated for electrical conductivity and electromagnetic shielding effect. When the thickness was 200 ㎛ or more, shielding effect 80 dB or more was satisfied at 1 GHz. However, in the case of Cu-Ni, there is little electrical conductivity at a thickness of 100 um or less due to the generated voids, and electromagnetic wave shielding performance cannot be expected. Therefore, To ensure electromagnetic shielding effect of structures, it is considered that the minimum thickness of metal spraying coating should be 200 um.