• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.354-354
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• 2015

코팅 층과 소지 사이의 접합력 평가를 위하여 박리 시험법(Peel Off Test), 블리스터 시험법(Blister Test), 압입균열 시험법(Indentation Test), 직접 인장 시험법(Direct Full Off Test), 스카치 테이프 시험법(Scotch Tape Test), 그리고 스크래치 시험법(Scratch Test) 등이 사용되어 왔다. 이 중 박리 시험법과 스카치 테이프 시험법이 산업계에서 일반적으로 사용되고 있다. 전자 산업계에서 많이 사용되고 있는 박리시험법은 금속박막과 절연체 기판 사이의 접합력을 간단하게 측정할 수 있으며, 실험값의 재현성이 뛰어난 장점이 있다. 또한, 측정하는 동안 만들어지는 박리 곡선(Peel Curve)로부터 분석의 신뢰성 여부를 확인할 수 있다. 이러한 장점에도 불구하고 박리 시험법 특성 상 금속 코팅층의 강도가 금속 피막/기판간 접합 강도를 초과하여야 하기 때문에 수백 nm 이하의 박막의 접합력 측정에는 적용하기가 어렵다. 이에 반하여, 스카치 테이프 분석법은 일정길이의 접착 테이프를 박막 표면에 붙인 후 다시 떼어내면서 접착력을 평가하는 방법으로, 박막의 접합력 평가에 적용이 가능하다. 그러나 이 방법은 합격 불합격 여부를 판정하는 정성적인 방법으로 정량평가가 어렵다. 또한, 박막에 접착 테이프를 붙일때의 압력, 테이프를 박리할 때의 각도 및 속도를 일정하게 제어하기가 쉽지 않아 결과의 신뢰성이 높지 않다. 스크래치 테스트는 탐사침(Stylus)을 이용하여 박막의 표면에 하중을 증가시키면서 기판을 이동하여, 피막의 균열이나 박리될 때의 임계 하중값 (Critical Load; Lc)을 측정하는 방법이다. 이 방법은 시편 준비가 쉽고 간단하여 빠른 분석이 가능하고, 수백 nm 이하의 박막에도 적용 가능하다. 또한, 접합력을 정량화 할 수 있기 때문에 변수에 따른 접합력 비교가 용이하다는 장점이 있다. 이와 같은 분석적 장점에도 불구하고, 스크래치 시험을 통한 접합력 측정 방법은 아직까진 산업적으로 널리 활용되지 못하고 있다. 따라서, 본 연구에서는 스크래치 테스트의 원리 및 이론에 대하여 간략히 알아보고, 스크래치 분석을 이용한 접합력 비교에 대한 실제 사례들을 소개하고자 하였다.

• Journal of Adhesion and Interface
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• v.10 no.4
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• pp.182-190
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• 2009

In this work, effect of antistrip additives to reduce moisture damage of asphalt mixture were studied. Asphalt antistripping agents were prepared by condensation of formaldehyde with tetraethylene pentamine (TEPA), triethylenetetramine (TETA) and bis(hexamethylene)-triamine (BHMT), respectively. And also the metal type antistripping agent was prepatred by neutralization of stearic acid or palmitic acid with metal hydroxide. Mechanical characteristics of the asphalt mixture added antistripping agent were evaluated with Marshall stability, submerging residuals and coating rate. It was found that antistripping agent prepared in this study reduced moisture damages of asphalt mixtures. In particular, asphalt mixtures added BHMT and C/S (Calcium stearate hydroxide) antistripping agent showed highest submerging and coating rate. Because BHMT and C/S type antistripping agent was to improve bonding between asphalt and aggregate owing to increase of amine concentration and role of metal surfactant.

• Nuclear Engineering and Technology
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• v.6 no.1
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• pp.14-22
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• 1974

Effects of anodization voltage on frequency characteristics of anodic oxide films on tantalum were analyzed based on the following impedance equatious : (equation omitted) Here $R_{f}$, $C_{f}$ and tan $\delta$$_{f}$ are equivalent series resistance in ohm, equivalent Belies capacitance in farad and dielectric loss, of anodic oxide films respectively Parameters P, $\tau$$_{ο}$, $\tau$$_{\omega}$, and Co are defined as follows: P=(d-w)/w, $\tau$$_{ο}$=$textsc{k}$$\rho$$_{ο}$, $\tau$$_{\omega}$=$textsc{k}$$\rho$$_{\omega}$, $C_{ο}$=$textsc{k}$A/d where d is the thickness of oxide film, $\omega$ is the diffusion layer thickness. $\rho$$_{ο}$ is the resistivity of oxide film at the interface of metal and the oxide, $\rho$$_{\omega}$ is the resistivity of oxide film at intrinsic region and A is the area of the film and $textsc{k}$=0.0885$\times$10$^{-12}$ $\times$dielectric constant, (in farad/cm). It was shown that dielectric loss and frequency dependence of equivalent series capacitance decrease as anodization voltage increases. This is a consequence of the fact that the thickness of diffusion layer increases a little with increasing anodization voltage whereas the total oxide thickness is proportional to the anodization voltage. The ngative deviation of measured values from tile relation, tan $\delta$$_{f}$=0.682 $\Delta$ $C_{f}$, was also discussed based on the Impedance equations given above. Here $\Delta$ $C_{f}$ is the change in capacitance between 0.1 and 1 KHZ.KHZ.Z.

• Journal of the Korean institute of surface engineering
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• v.54 no.2
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• pp.90-95
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• 2021

Surface modification technique enabling the control of condensation provides various benefit in various engineering systems, such as heat transfer, desalination, power plants, and so on. In this study, lubricant oil-impregnation into Teflon-coated nanoporous anodic oxide layer of aluminum to enhance a de-wetting and mobility of water droplet on surface. Due to the surface treatment improving water-repellency, the condensation mode is changed to dropwise, thus the frequency of sliding condensed water droplet on surface is increased. For these reasons, the surface of oil-impregnated Teflon-coated nanoporous anodic aluminum oxide shows significantly enhanced condensation heat transfer compared to bare aluminum surface. In addition, the porosity of anodic aluminum oxide affected the mobility of water droplet even with oil-impregnation and Teflon-coating, indicating that the optimization of porous structure of anodic oxide is required for maximizing the condensation heat transfer.

• Journal of Conservation Science
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• v.33 no.5
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• pp.381-390
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• 2017

Desalination is the main focus of the stabilization of iron artifacts. However, drawbacks such as re-corrosion are noted due to the uncertainty in the elimination of the corrosive factors and artifacts. Several studies have been carried out on the effects of corrosion inhibitors to overcome these shortcomings. In this study, the effects of type 3 water treatment on corrosion inhibitors were investigated. Surfaces of samples that contained film corrosion inhibitors on their surfaces were analyzed. The results revealed that the surface rust was removed from the sample of type 1 No. 2 that was mainly composed of phosphate. The average weight reduction rates of re-corrosion samples were 0.58, 0.03, and 0.07% for type 1 No. 2, type 2 No. 2, and type 3 No. 2 respectively. The changes in the $Cl^-$ ion, a corrosive agent were found to be 28.60, -4.08, and -1.94 ppm for type 1 No. 2, type 2 No. 2, and type 3 No. 2 respectively. The water-treated films were analyzed by X-ray photoelectron spectroscopy (XPS). It was found that type 2 No. 2 had less Fe the basis metal, than that in type 3 No. 2 indicating much better film. Moreover, Si content was higher in type 2 No. 2, based on the silicate content, than in type 3 No. 2. They are speculated to be the reason or the formation of a better film. Type 1 No. 2, which is mainly composed of phosphate, would be inappropriate as a metal artifact conservation treatment. It was determined that type 2 No. 2 and type 3 No. 2 water treatments, which are mainly composed of silicate, provided excellent corrosion inhibiting effects. Corrosion inhibitors could be used as emergency treatment agents during the excavation of iron artifacts.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.12
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• pp.1251-1256
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• 2015

This study investigates the friction noise characteristic in relation to the corrosion of metal by using the frictional reciprocating and pin-on-disk system. From the experiments, it is found that the corrosion of metal advances the onset time and increases the magnitude of friction noise. Further, it is observed that the effect of corrosion on friction noise stems from the alteration of tribo-surface during repetitive frictional motion. The alteration of the corrosive contact surface induces a negative friction-velocity slope, by which the corrosion of metal can generate dynamic instability faster than non-corrosion of metal.

• Journal of the Korean institute of surface engineering
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• v.54 no.5
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• pp.222-229
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• 2021

Icing causes various serious problems, where water vapor or water droplets adhere at cold conditions. Therefore, understanding of ice adhesion on solid surface and technology to reduce de-icing force are essential for surface finishing of metallic materials used in extreme environments and aircrafts. In this study, we controlled wettability of aluminum alloy using anodic oxidation, hydrophobic coating and lubricant-impregnation. In addition, surface porosity of anodized oxide layer was controlled to realize superhydrophilicity and superhydrophobicity. Then, de-icing force on these surfaces with a wide range of wettability and mobility of water was measured. The results show that the enhanced wettability of hydrophilic surface causes strong adhesion of ice. The hydrophobic coating on the nanoporous anodic oxide layer reduces the adhesion of ice, but the volume expansion of water during the freezing diminishes the effect. The lubricant-impregnated surface shows an extremely low adhesion of ice, since the lubricant inhibits the direct contact between ice and solid surface.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2013.05a
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• pp.58-58
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• 2013

폴리에스테르 필름상에 무전해 Cu 도금 및 무전해 Ni-P 도금층을 형성하는 방법으로 박형 전자파 차폐 필름의 제조에 대하여 연구 하였다. 무전해 도금의 전처리 방법으로 기존의 Pd 촉매를 사용하는 대신에, 증착법에 의한 Sn 피막의 형성으로 전자파 차폐 특성 및 유연성이 우수한 박형 전자파 차폐 필름의 형성이 가능하게 되었다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2013.05a
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• pp.133-134
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• 2013

본 연구는 비전도성 소재 상에 무전해 동도금(Electroless Copper)시 수행되는 씨앗층이나 촉매공정 없이 직접 구리 석출물을 얻는 방법 중 하나에 관한 연구이다. 실리콘 웨이퍼상에 확산방지를 위한 Ta 금속확산방지(Metal barrier)막층 형성 후 무전해 동도금에 침지 후 최소한의 전류를 인가한 결과 균일한 구리피막을 얻을 수 있었으며, 표면 및 단면 조직 분석결과 이를 확인할 수 있었다.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.40-45
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• 1998

Th-232를 Fertile 핵연료로 사용한 압력관형 고전환 경수로심을 설계하였다. 토륨 Blanket은 10년 정도 노내에 위치시키고, 농축 우라늄 Driver는 매년 재장전하도록 설계하였다. Driver로는 $UO_2$핵연료와 U-10%Zr 금속 핵연료를 사용하였고, Blanket으로 이중 탄소 피막 핵원료를 ThO$_2$에 적용한 핵연료를 사용하였다. 핵연료봉의 구조는 울진 3/4호기 핵연료와 같은 재원으로 하였으며 육각형 격자 배열로 집합체를 구성하였다. Seed Bundle을 1년 단위로 교체하고 Blanket Bundled을 5년-10년간 노내에 위치시키는 경우 경수로보다는 높은 전환율 갖는 원자로를 설계할 수 있다.