• Proceedings of the Korean Magnestics Society Conference
• /
• 2017.05a
• /
• pp.138-138
• /
• 2017

• Proceedings of the Korean Magnestics Society Conference
• /
• 2005.12a
• /
• pp.145-145
• /
• 2005

• Composites Research
• /
• v.20 no.5
• /
• pp.43-48
• /
• 2007

The absorption and the interference shielding of electromagnetic wave have been very important issues for commercial and military purposes. The stealth technique is one of the most typical applications of electromagnetic wave absorption technology. This study has started for the development of composite fillers containing dielectric and magnetic lossy materials. To improve the electromagnetic characteristics of conductive nano fillers, carbon nanofibers (CNFs) with nickel-phosphorous (Ni-P) or nickel-iron (Ni-Fe) have been fabricated by the electroless plating process. Observations by the electron microscopy (SEM/TEM) and element analyzer (EDS/ELLS) showed the uniform Ni-P and Ni-Fe coated CNFs. The compositions of the plating layers were about Ni-6wt%P and Ni-70wt%Fe, respectively. The average thicknesses of the plating layers were about $50\;{\sim}\;100\;nm$.

• Composites Research
• /
• v.28 no.6
• /
• pp.333-339
• /
• 2015

Electromagnetic interference shielding composite with low density ($1.18g/cm^3$) was fabricated using electroless plated FeCo magnetic metal hollow fibers and ethylene propylene diene monomer (EPDM) polymer. Aspect ratio of the fibers were controlled and their hollow structure was obtained by heat treatment process. The FeCo hollow fibers were then mixed with EPDM to manufacture the composite. The higher aspect ratio of the magnetic metal hollow fibers resulted in high electromagnetic interference shielding effectiveness (30 dB) of the composite due to its low sheet resistance (30 ohm/sq). The enhanced electromagnetic interference shielding effectiveness was mainly attributed to the formation of conducting network over the percolation threshold by high aspect ratio of fibers as well as an increase of the reflection loss by impedance mismatch owing to low sheet resistance, absorption loss, and multiple internal reflections loss.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2012.05a
• /
• pp.221-222
• /
• 2012

2000년 미국에서 국가나노기술개발 전략을 발표한 이래로 현재 한국, 일본, 유럽연합, 독일, 중국, 대만 등 전 세계 60여개 국가들은 나노기술을 미래 국가 경쟁력을 결정하는 핵심요소로 인식하고, 나노국가기술개발 전략을 수립하고 경쟁하고 있다. 한국은 제 1기 나노기술종합발전계획(2001.7)과 제 2기 나노기술종합발전계획(2005.12)의 수립, 추진을 통하여 지난 10여 년 동안 나노기술연구개발, 첨단 연구시설 구축, 나노전문 인력양성, 나노기술산업화 등의 분야에서 괄목할 만한 많은 성과들을 이룩해 왔다. 특히 한국은 나노기술 경쟁구도에 있어 분기점으로 될 것으로 예상되는 2015년에 나노기술 3대 강국 진입을 목표로 설정하고, 정부의 적극적인 투자와 연구자들의 헌신적인 노력이 경주되고 있다. 최근 스마트폰 등, 이동통신기 대량보급과 함께 나노소재는 암 치료나 생체재료분야의 연구개발이 활성화되고 있다. 본고에서는 최근의 나노자성도금의 특성을 중심으로 기술하였다.

• Journal of Korean Ophthalmic Optics Society
• /
• v.7 no.1
• /
• pp.35-38
• /
• 2002

Ferrite thin film with glass substrate was prepared by ferrite plating method in order to make sunglass which cut off ultraviolet and electromagnetic field. It has single phase of polycrystalline spinel structure and has gloss like as mirror and has hardness without scratch by scraping with nail. The transmittance of ferrite thin film is lowered near 400nm manifestly, which shows that the ferrite thin film was cut off ultraviolet successfully. Therefore, the sunglass with ferrite plating is use of cut of ultraviolet and electromagnetic field.

• Journal of the Korean institute of surface engineering
• /
• v.19 no.1
• /
• pp.3-12
• /
• 1986

Influences of pH, temperature, and composition of bath on the deposition rate and the magnetic properties were studied for two kinds of electroless Co-P plating bath. The results obtained are as follows. Ammonia alkaline citrate bath was more stable than ammonia alkaline tartrate bath, and the film deposited from citrate bath gave a higher squareness. The magnetic properties of the film obtained from citrate bath greatly depended upon pH. Under the optimum conditions, the film deposited from citrate bath had coercive force of 330 Oe and squareness of 0.67. However the films deposited from tartrate bath had coercive force of 300 Oe and squareness of 0.58.

• Journal of the Korean Magnetics Society
• /
• v.23 no.6
• /
• pp.188-192
• /
• 2013

The magnetic interaction effect on the magnetic activation volume and area of electrodeposited CoPt magnetic films was investigated. The dipolar interaction was predominant interaction mechanism for all samples. And the interaction strength was increased with decreasing current density and increased with increasing sample thickness. Although the activation volumes of the samples fabricated at low current density were larger than those of the high current density samples, the sample thickness seemed to have little influence on the variation of activation volume. But it was found that the activation area was apparently affected by the magnetic interaction strength as well as the current density.

• Journal of the Korean Electrochemical Society
• /
• v.5 no.2
• /
• pp.57-61
• /
• 2002

In this study, the effect of ammonium chloride on the electrodeposition of CoP magnetic alloy film was investigated. The correlation between the electrodeposition condition and the magnetic properties was tried to elucidate by the electro- analytical tests such as cyclic voltammetry. It was observed that the magnetic properties of the films were varied extensively with the ammonium chloride contents in the solution. The reason why the magnetic properties of the films were varied with the addition of ammonium chloride was thought that the addition of ammonium chloride controlled the electrocrystallization of CoP kinetically by charge transfer and increased the grain size and the orientation factor. This may cause the variation of the magnetic properties of CoP films.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.28 no.5
• /
• pp.395-400
• /
• 2008

Alternating magnetic field was used for detection of surface flaws on nonmagnetic and magnetic metallic specimens. The nondestructive sensor probe was composed of the planar coil with inductive magnetic thin film yoke as a sensing component and a single straight typed exciting coil. The planar inductive coil sensor with magnetic yoke was fabricated by sputtering, electroplating, dry etching and photolithography process. The alternative currents with the range of 0.1A to 1.0A (0.7 MHz to 1.8 MHz) were applied to the exciting coil. The specimens were prepared with the slit shaped artificial surface flaws (minimum depth and width; 0.5 mm) on metallic plate (Al; nonmagnetic metal and FeC; magnetic metal). The detected signal for the positions and shapes of surface flaws on specimens were obtained with high sensitivity and high signal to ratio. The measured output signals by the non-contacted scanning on surface of FeC specimen with micron-sized crack were converted to the images of the flaws. And these results were compared with the optical images, respectively.