• Journal of the Korea Institute of Building Construction
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• v.20 no.6
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• pp.481-488
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• 2020

The arc thermal metal spraying method (ATMSM) has been used in Korea to improve the electromagnetic pulse (EMP) shielding effect of building and infrastructure by three machines of MS, KMS and HMS (Metal Spray, Korea Metal Spray, High-frequency Meta Spray). The adhesion ability of sprayed metal was found to be 58.32, 64.66 and 87.62% for MS, KMS and HMS, respectively. The metal sprayed area per hour of MS, KMS and HMS was calculated and found to be 14.3, 19.25 and 22.16㎡/h, respectively. The HMS showed the highest metal spray area attributed to the diameter of metal wire i.e. 1.6mm which sprayed 80 mm with 18 m/min. There was minimum loss of metal and the highest efficiency by HMS compared to others. Therefore, it is suggested to use HMS for metal spraying by ATMSM to enhance the EMP shielding effect.

• Journal of the Korea Institute of Building Construction
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• v.16 no.2
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• pp.107-115
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• 2016

In this study, the bond strength of metal spraying system by surface treatment of concrete (waterproof/corrosion method) in water treatment facilities was evaluated. The results showed that the system with Sa-P-R-(S) (sanding-perviousness surface hardener-surface roughness agent-metal spraying-sealing) led to the desirable performance. The bond strength, the coefficient of water permeability and air permeability were 3.7MPa, $0.68{\ast}10^{-8}cm/sec$, and $0.45{\ast}10^{-16}m^2$, respectively. In scanning electron microscope analysis, the microstructure of specimen coated with perviousness surface hardener was much denser than that without it. Therefore, the specimen coated with sanding-perviousness surface hardener-surface roughness agent-metal spraying-sealing had the best bond performance and was the most suitable system to concrete surface in water treatment facilities.

• Journal of the Korea Concrete Institute
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• v.29 no.2
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• pp.169-177
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• 2017

Rather than causing damage from heat, blast, and radiation of a regular nuclear weapon, recently, it is predicted that North Korea has been inventing high altitude electromagnetic pulse (HEMP) missile in order to incapacitate electronic equipment. HEMP shielding facility is used for military purpose today. Despite the electromagnetic shielding effects from high quality compression plates, problems may include such as the possibility of electromagnetic influx resulting in the welding of the compression plates, and difficulties and high cost of construction. Therefore, in this study, a high electrical conducting material was added to the concrete experimental subject to ensure the shielding effect through electromagnetic waves to for the concrete structure, instead of building a shielding facility separately for the structure. Also, among the experimental subjects, 100 ${\mu}m$ of Iron-Aluminum alloy metal spraying coat was applied to two types with the highest shielding effect, and to two types with the lowest shielding effect. The result of the experiment indicates that experimental subjects added with a high electrical conductivity material did not meet the minimum shielding criteria of MIL-STD-118-125-1 standard, but all the experimental material applied to the metal spraying coating satisfied the minimum shielding criteria. In conclusion, it is considered that 100 µm of Iron-Aluminum alloy metal spraying coat contains high efficiency in the HEMP shielding.

• Journal of the Korea Institute of Building Construction
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• v.19 no.3
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• pp.209-217
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• 2019

EMP (Electromagnetic Pulse) usually means High Power Electromagnetic Wave (HPEM). In the case of the shielding plate against the EMP, there is a possibility of deterioration of the electromagnetic wave shielding performance due to the skill of the constructor, bad construction, deformation of the shielding plate at the connection portion (joint portion). The inefficient use of space due to the separation distance is also pointed out as a problem. Therefore, this study aims to derive the optimum electromagnetic shielding condition by applying ATMSM to concrete as a part of securing electromagnetic wave shielding performance with reflection loss against concrete wall. Experimental parameters included concrete wall thickness and application of Zn-Al ATMSM. For the concrete wall, the wall thickness was 100 to 300mm, which is generally applied, and experimental parameters were set for the application of Zn-Al metal spraying method to evaluate electromagnetic shielding performance. Experimental results showed that as the thickness increases, the electromagnetic shielding performance increases due to the increase of absorption loss. In addition, after the application of Zn-Al ATMSM, the average shielding performance increased by 56.68 dB on average, which is considered to be increased by the reflection loss of the ATMSM. In addition, it is considered that the shielding performance will be better than that when the conductive mixed material and the ATMSM are simultaneously applied.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.5
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• pp.670-677
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• 2010

There are many surface protection methods for numerous steel structures being used under severely corrosive environment, one of them, metallizing(thermal spray) is a available protection method which is comparatively and recently developed for surrface protection of various steel structures. However coating film obtained by spraying is to be needed increasingly more good corrosion resistance due to accelerating of environmental contamination. In this study, coating films(DFT:$200{\mu}m$) are performed with arc spray by wire metal and their types of films are pure zinc, pure aluminum, alloy film(Al:Zn=85:15) and alloy film(Al:Zn=95:5). And corrosion resistance of their films was investigated with electrochemical methods in seawater solution. Pure aluminum film showed a relatively somewhat good corrosion resistance compared to among those of other films and alloy films also showed a good corrosion resistance compared to pure zinc film. Especially it was observed that pure aluminum film showed a comparatively good corrosion resistance than that of alloy film named as galvarium spray(Al:Zn=85:15) in seawater solution. Morphology of corroded surface of pure zinc film appeared the pattern like intergranlar corrosion, however films of pure aluminum and alloy metal showed a general corrosion pattern.