• Journal of Korean Electronics
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• v.3 no.7
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• pp.138-146
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• 1983

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2000.05a
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• pp.21-21
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• 2000

• Journal of Korean Electronics
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• v.2 no.10
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• pp.57-69
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• 1982

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.9
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• pp.1307-1312
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• 2013

In this paper, alkaline or acidic solution, in particular the principle of electrolysis to oxidize the metal surface to form a device isolation film is developed. In the past, mainly in the form of pulse voltage is applied to the anode only a unipolar method, but in this paper by using the H-bridge to the amount of the positive (+) voltage and the negative supply voltage, alternating voltage polarity devices were fabricated according to the characteristics of metal specimens with different electrical conditions to form an oxide film on the device was developed. Supply current variable was used for the PWM modulation, (+) and (-) polarity change of the H-bridge bipolar pulse voltage to supply the was that. As a result, a more uniform pores with unipolar film was formed.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.3
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• pp.355-362
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• 2011

In this paper, we developed the equipment to forming the insulation film which there are operated an electrolysis principles in particular solution. In the earlier, there are supplied the anode by unipolar voltage with pulse, in this paper, there are supplied the anode by bipolar voltage with pulse, alternately. And then, we examinate the system that there are developed the bipolar anodizing equipment using H-bridge. There are modulated pulse width for the variable current. In the results, we obtained the results of the uniform film surface that compared with the unipolar anodizing.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1999.05a
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• pp.89-89
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• 1999

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1998.11a
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• pp.21-21
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• 1998

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.298-298
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• 2013

플라즈마 전해산화기술은 알루미늄 소재에 대해 기존의 양극 산화막, 전해 경질크롬 도금 및 플라즈마 세라믹 용사기술 등에 의해 구현할 수 없는 고기능성을 부여하여 월등히 우수한 경도, 내부식, 내마모, 전기절연, 열저항, 피로강도 등을 얻을 수 있는 획기적인 기술이다. 또한 최근 환경에 대한 관심이 점차 높아지면서 친환경적 공정과정과 경금속 소재의 제품에 내구성을 향상시킬 필요성이 높아지고 있다. 이러한 요구에 부합하는 플라즈마 전해 산화기술은 알칼리 수용액 중에서 Al, Ti, Mg 등의 표면에 산화 피막을 형성시키는 기술로써 기존의 양극산화(Anodizing)을 대체 할 수 있다. 본 연구에서는 Al6061을 이용하여 플라즈마 전해산화 공정에 사용되는 전해액의 종류 및 농도, 시간의 변화에 따른 산화 피막의 변화를 내전압 측정 및 FE-SEM, EDS, XRD를 통해 분석하였다. 전해액에 sodium hexameta phosphate과 potassium phosphate를 이용하여 phosphate 종류의 변화에 따른 피막 특성의 변화를 연구하였다. 그로인해 phosphate의 종류 및 농도, 시간 변화를 이용하여 플라즈마 전해산화공정의 산화 피막 물성 제어를 할 수 있다.

• Fire Science and Engineering
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• v.32 no.6
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• pp.1-6
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• 2018

This study is to analyze the characteristics of the yellow insulation ring type of the CSST used for tubing when it is artificially deteriorated and damaged by burning. The CSST for tubing consists of a tube, protective coating, nut, yellow insulation ring, packing, and socket. In addition, it is thought that a yellow insulation ring and rubber packing were used to connect the tube and socket in order to improve the airtightness and insulation performance. The result of the verification of the data acquired from the tests in the 95% confidence interval shows that the Anderson-Darling (AD) and P value were analyzed to be 0.945 and 0.015, respectively. This confirms that the test data of the CSST for tubing is reliable. The analysis of the arithmetic mean of the insulation resistance of a CSST showed that the CSST damaged by burning by a torch, and the one damaged by electrical burning, was $16.7k{\Omega}$ (the greatest relatively) and $208{\Omega}$ (the lowest), respectively, while it was $1.72k{\Omega}$ in the case of a normal product. Therefore, the analysis result of the insulation resistance of the CSST collected from the scene of a fire can be utilized to examine the cause of damage by burning. In addition, it was found that when the maximum current of 97 A was applied to the CSST for about 5 s using a Primary Current Injection Test System (PCITS) the protective film and insulation ring of the CSST has no difference from that of a normal product. However, a part of the metal tube was melted.

• Journal of the Korean Magnetics Society
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• v.15 no.5
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• pp.270-275
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• 2005

Dust cores (compressed powder cores) of $Fe-6.0wt\%Si$ alloy with a size of $35\~180\;{\mu}m$ in diameter have been prepared by phosphate coatings and annealings at $600\~900^{\circ}C$ for 1 h in nitrogen atmosphere. Further the magnetic and mechanical properties of the powder cores were investigated. As a general trends, the compressive strength and core loss decreased with the increase in annealing temperature. When annealed at $800^{\circ}C$, the compressive strength was 15 kgf, the permeability and quality factor were 74 and 26, respectively. Moreover the core loss at 50 kHz and 0.1 T induction was $750\;mW/cm^3$, and the percent permeability under the static field of 50 Oe was estimated to be about 78. In addition, the cut-off frequency in the cure representing the frequency dependence of effective permeability was measured to be around 200 kHz. These properties of the $Fe-6.0wt\%Si$ alloy dust cores could be considered to be due to the good insulation effect of iron-phosphate coats, the decrease in magnetocrystalline anisotropy and saturation magnetostriction and the increase in electric resistivity.