• Journal of Conservation Science
• /
• v.27 no.2
• /
• pp.135-144
• /
• 2011

When metal artifacts have to undergo conservation treatment, the person in charge of the treatment selects and uses various coating mixtures based on his judgment regarding their condition, material, or environment. Since the kinds of coating mixtures or solvents make a difference in the set time of cyanoacrylate adhesives, they have something to do with the efficiency of the conservation treatment. This study examines the effects and causes that affect the set time of cyanoacrylate adhesives according to the kinds of coating mixtures and solvents and suggests ways to increase the set time. As a result, it is thought that as the surface roughness gets flatter, the wettability of adhesive is improved further, which increases the set time. Moreover, the C-F binding of V-Flon, C-O-C absorption peak, molecular weight of the coating mixtures, and glass transition temperature (Tg) were the factors that significantly affected the set time. According to the result of measuring the set time based on the result of superficial and chemical analysis, relative difference was shown according to the kind and viscosity of adhesive, but all the adhesives indicated the following order of the set time: V-Flon > Paraloid B-72 (in xylene) > Paraloid NAD-10 > Paraloid B-72 (in acetone).

• Journal of Adhesion and Interface
• /
• v.24 no.2
• /
• pp.41-53
• /
• 2023

The deformable devices refer to the devices that can maintain their initial performance even when stretched or bent. Among the materials used as conductor in deformable devices, Ga-based liquid metal is one of the most promising materials because it can provide not only high conductivity and deformability but also low toxicity. In this paper, we introduce Ga-based liquid metals and then discuss the recent research trend in deformable devices composed of Ga-based liquid metal.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.21 no.4
• /
• pp.425-433
• /
• 2001

A correlation between fatigue damage and acousto-ultrasonic (AU) parameters has been obtained from signals acquired during fatigue loading of the single-lap joints of a carbon-fiber reinforced plastic (CFRP) laminates and A16061 plate. The correlation showed an analogy to those representing the stiffness reduction $(E/E_0)$ of polymer matrix composites by the accumulation of fatigue damage. This has been attributed to the transmission characteristics of acoustic wave energy through bonded joints with delamination-type defects and their influence on the change of spectral content of AU signals. Another correlation between fatigue cycles and the spectral magnitude of acoustic emission (AE) signals has also been found during the final stage of fatigue loading. Both AU and AE can be applied almost in real-time to monitor the evolution of damage during fatigue loading.

• Composites Research
• /
• v.31 no.5
• /
• pp.177-185
• /
• 2018

Fiber metal laminate (FML) is a type of hybrid composites which consist of metallic and fiber-reinforced plastic sheets. As the FML has a drawback of the delamination that is a failure of the interfacial adhesive layer, the nominal stresses and the energy release rates should be determined to identify the delamination behavior. However, it is difficult to derive the nominal stresses and the energy release rates since the operating temperature of the equipment is restricted. For this reason, the objective of this paper is to predict the mode-I nominal stress and the mode-I energy release rate of the adhesive layer using the inverse analysis based on the Levenberg-Marquardt method. First, the mode-I nominal stress was assumed as the tensile strength of the adhesive layer, and the mode-I energy release rate was obtained from the double cantilever beam test. Next, the finite element method was applied to predict the mode-I delamination behavior. Finally, the mode-I nominal stress and the mode-I energy release rate were predicted by the inverse analysis. In addition, the convergence of the parameters was validated by trying to input two cases of the initial parameters. Consequently, it is noted that the inverse analysis can predict the mode-I delamination behavior, and the two input parameters were converged to similar values.

• Composites Research
• /
• v.29 no.2
• /
• pp.45-52
• /
• 2016

An understanding of the failure mechanisms of the adhesive layer is decisive in interpreting the performance of a particular adhesive joint because the delamination is one of the most common failure modes of the laminated composites such as the fiber metal laminates. The interface between different materials, which is the case between the metal and the composite layers in this study, can be loaded through a combination of fracture modes. All loads can be decomposed into peel stresses, perpendicular to the interface, and two in-plane shear stresses, leading to three basic fracture mode I, II and III. To determine the load causing the delamination growth, the energy release rate should be identified in corresponding criterion involving the critical energy release rate ($G_C$) of the material. The critical energy release rate based on these three modes will be $G_{IC}$, $G_{IIC}$ and $G_{IIIC}$. In this study, to evaluate the fracture behaviors in the fracture mode I and II of the adhesive layer in fiber metal laminates, the double cantilever beam and the end-notched flexure tests were performed using the reference adhesive joints. Furthermore, it is confirmed that the experimental results of the adhesive fracture toughness can be applied by the comparison with the finite element analysis using cohesive zone model.

• Composites Research
• /
• v.30 no.3
• /
• pp.181-187
• /
• 2017

The effect of nanoscopic and microscopic Fe, $Fe_3O_4$, and Ni particles and their shapes and substrate materials on the heating behavior of thermoplastic polyurethane (TPU) adhesive films was investigated via induction heating. The heat generation tendency of $Fe_3O_4$ particles was higher than that shown by Fe and Ni particles in the TPU adhesive films. When the Fe and Ni particle size was larger than the penetration skin depth, the initial heating rate and maximum temperature increased with an increase in the particle size. This is attributed to the eddy current heat loss. The heating behavior of the TPU films with Ni particles of different shapes was examined, and different hysteresis heat losses were observed depending on the particle shape. Consequently, the flake-shaped Ni particles showed the most favorable heat generation because of the largest hysteresis loss. The substrate materials also affected the heating behavior of the TPU adhesive films in an induction heating system, and the thermal conductivity of the substrate materials was determined to be the main factor affecting the heating behavior.

• Journal of Adhesion and Interface
• /
• v.24 no.3
• /
• pp.105-111
• /
• 2023

Recently, there has been a growing interest in low biofouling coatings for various industrial applications including precious metal and jewelry applications. Contaminations including cells and bacteria of the metallic substrates (i.e., accessories, earring, and piercings) may irritate the contacted tissue surfaces or induce an abnormal reaction. In this study, catechol-conjugated polyethylene glycol (PEG-C) was synthesized as low bio-fouling coating materials inspired by mussel-adhesion. PEG-C-coated copper-zinc alloy surfaces showed excellent cell viability and significant inhibitions of protein and cell adhesions to metal surfaces. Thus, PEG-C coating methods and PEG-C-coated metallic substrates can be usefully exploited for versatile industrial applications, particularly for precious metal and jewelry industries.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.494.1-494.1
• /
• 2014

태양광은 세계적으로 유망한 에너지 중의 하나이며, 태양광 모듈은 실제 옥외 조건에 따라 다르지만 장기 신뢰성과 수명을 보장하기 위해 최소 20년 이상을 안정적으로 작동될 필요성이 있다. 하지만 실제 태양전지는 옥외에 장기 노출됨에 따라 성능이 저하되며, 그 원인으로는 셀 균열, 부식, 접착 강도 손실 및 박리, 그리고 변색 등이 있다. 본 논문에서는 부식으로 인한 성능 저하를 완화하기 위해 희생금속을 이용하여 태양전지 모듈의 성능 향상에 대해 연구하였다. 태양전지는 4 cell 결정질 실리콘 태양전지 미니 모듈을 이용하였고, 희생금속의 영향을 확인하기 위해 두 종류의 시료를 준비하였다. 한 시료에는 Al 희생금속을 태양전지 리본 위에 부착하였으며, 나머지 한 시료는 비교 시료로 Al 희생금속을 부착하지 않았다. 시료는 $85^{\circ}C$ 85%의 상대습도인 고온고습 조건에서 2500시간을 진행하였다. 그리고 2500시간의 고온고습 시험이 진행된 시료의 전기적 특성을 분석하였다. 시험 결과, 희생금속이 없을 경우 28.8%의 출력 저하가 있었으며, 희생금속이 있을 경우 19.3%의 출력 저하가 확인되었다. 또한, 희생금속이 없을 경우, 충실도는 21.5% 감소하였으며, 단락전류 역시 약 6% 정도 감소하였다. 반면, 희생금속이 있을 경우, 충실도는 16.1%로 감소하였고, 단락전류는 거의 변화가 없었다.

• Journal of Conservation Science
• /
• v.25 no.3
• /
• pp.273-282
• /
• 2009

As a result of investigating research papers concerning the metal bound rim decoration on four pieces of 'Bowl, white porcelain with impressed floral design and sliver bound rim' and one piece of 'Bowl, white porcelain with sliver bound rim' from among the Jingdezhen white porcelain, which are Sinan remains that are kept in a National museum of Korea. It was found that the material of the bound rim was not silver but tin, and lacquer was used as glue. Based on such a scientific analysis, this study conducted a reproduction test of the manufacturing technique and the bonding method of the metal bound rim attached to the upper tip of the china ware. As a way of reproducing the bound rim, the study was able to discover the best method in terms of the avoidance of loss of materials and the workability out of various cutting methods for tin plates, and it also discovered that the use of lacquer in mixture with soil showed a better workability than the use only of a lacquer ingredient in a test of the bonding method of a metal bound rim using lacquer. Also, in the test of a drying method, a bonding method after drying within a short time at a relatively high temperature was found to be more effective than the drying method after humidifying at a normal temperature, which is used in traditional lacquer ware preservation treatment.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.05a
• /
• pp.159-159
• /
• 2004

금속 박막 위의 알칸티올분자의 흡착에 의한 자기조립단분자막(Self-Assembled Monolayers)은 접착 방지, 마찰 저하 등의 기능을 가진 코팅층으로서의 응용과 분자 또는 생분자의 미세 구조물 형성을 위한 방법으로 널리 연구되어지고 있다. 이러한 연구 중에서 특히 자기조립단분자막의 매우 얇은 두께와 금속 박막의 선택적 식각을 위한 안정적인 리지스트(Photo Resist)로서의 특징을 활용한 극미세 패터닝에 대한 연구가 활발히 진행되고 있다.(중략)