• 제목/요약/키워드: adhesive layer

검색결과 543건 처리시간 0.025초

지오폴리머 시멘트를 이용한 콘크리트 표면의 패각 분말 코팅 (Shell Powder Coating on the Surface of Concrete by Geopolymer Cement)

  • 김갑중;한현근;서동석;이종국
    • 한국재료학회지
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    • 제20권1호
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    • pp.1-6
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    • 2010
  • Geopolymer materials are attractive as inorganic binders due to their superior mechanical and eco-friendly properties. In the current study, geopolymer-based cement was prepared using aluminosilicate minerals from fly-ash with KOH as an alkaline-activator and $Na_2SiO_3$ as liquid glass. Then, calcium carbonate powder from a clam shell was mixed with the geopolymer and the mixture was coated on a concrete surface to provide points of attachment for environmental organisms to grow on the geopolymers. We investigated the effect of the shell powder grain size on the microstructure and bonding property of the geopolymers. A homogeneous geopolymer layer coated well on the concrete surface via aluminosilicate bonding, but the adhesiveness of the shell powder on the geopolymer cement was dependent on the grain size of the shell powder. Superior adhesive characteristics were shown in the shell powder of large grain size due to the deep penetration into the geopolymer by their large weight. This kind of coating can be applied to the adhesiveness of eco-materials on the surface of seaside or riverside blocks.

폴리카보네이트에서의 표면개질 조건과 DC-Bias Sputtering 증착에 따른 Cu 밀착성 (Adhesion of Cu on Polycarbonate with the Condition of Surface Modification and DC-Bias Sputtering Deposition)

  • 배길상;엄준선;이인선;김상호;고영배;김동원
    • 한국표면공학회지
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    • 제37권1호
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    • pp.5-12
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    • 2004
  • The enhancement of adhesion for Cu film on polycarbonate (PC) surface with the $Ar/O_2$ gas plasma treatment and dc-bias sputtering was studied. The plasma treatment with this reactive mixture changes the chemical property of PC surface into hydrophllic one, which is shown by the variation of contact angle with surface modification. The micro surface roughness that also gives the high adhesive environment is increased by the $Ar/O_2$ gas plasma treatment. These results were observed distinctly from the atomic force microscopy (AFM). The negative substrate dc-bias effect for the Cu adhesion on PC was also investifated. Accelerated $Ar^{+}$ lons in sheath area of anode bombard the bare surface of PC during initial stage of dc bias sputtering. PC substrate. therefore, has severe roughen and hydrophilic surface due to the physical etching process with more activated functional group. As dc-bias sputtering process proceeds, morphology of Cu film shows better step coverage and dense layer. The results of peel test show the evidence of superiority of bias sputtering for the adhesion between metal Cu and PC.C.

팔라듐 합금 수소분리막의 내구성 향상 (Improvement in Long-term Stability of Pd Alloy Hydrogen Separation Membranes)

  • 김창현;이준형;조성태;김동원
    • 한국표면공학회지
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    • 제48권1호
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    • pp.11-22
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    • 2015
  • Pd alloy hydrogen membranes for hydrogen purification and separation need thermal stability at high temperature for commercial applications. Intermetallic diffusion between the Pd alloy film and the porous metal support gives rise to serious problems in long-term stability of Pd alloy membranes. Ceramic barriers are widely used to prevent the intermetallic diffusion from the porous metal support. However, these layers result in poor adhesion at the interface between film and barrier because of the fundamentally poor chemical affinity and a large thermal stress. In this study, we developed Pd alloy membranes having a dense microstructure and saturated composition on modified metal supports by advanced DC magnetron sputtering and heat treatment for enhanced thermal stability. Experimental results showed that Pd-Cu and Pd-Ag alloy membranes had considerably enhanced long-term stability owing to stable, dense alloy film microstructure and saturated composition, effective diffusion barrier, and good adhesive interface layer.

상압 플라즈마 표면처리를 통한 태양광모듈 커버글라스와 불소계 코팅의 응착력 향상 (Improved Adhesion of Solar Cell Cover Glass with Surface-Flourinated Coating Using Atmospheric Pressure Plasma Treatment)

  • 김태현;박우상
    • 한국전기전자재료학회논문지
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    • 제31권4호
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    • pp.244-248
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    • 2018
  • We propose a method for improving the reliability of a solar cell by applying a fluorinated surface coating to protect the cell from the outdoor environment using an atmospheric pressure plasma (APP) treatment. An APP source is operated by radio frequency (RF) power, Ar gas, and $O_2gas$. APP treatment can remove organic contaminants from the surface and improve other surface properties such as the surface free energy. We determined the optimal APP parameters to maximize the surface free energy by using the dyne pen test. Then we used the scratch test in order to confirm the correlation between the APP parameters and the surface properties by measuring the surface free energy and adhesive characteristics of the coating. Consequently, an increase in the surface free energy of the cover glass caused an improvement in the adhesion between the coating layer and the cover glass. After treatment, adhesion between the coating and cover glass was improved by 35%.

Plasma-Sprayed $Al_{2}O_{3}-SiO_{2}$ Multi-Oxide Films on Stainless Steel Substrate

  • Korobova, N.;Soh, Deawha
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2000년도 추계학술대회 논문집
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    • pp.116-119
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    • 2000
  • The advantage of plasma-sprayed coating is their good resistance against thermal shock due to the porous state of the coated layer with a consequently low Youngs modules. However, the existence of many pores with a bimodal distribution and a laminar structure in the coating reduces coating strength and oxidation protection of the base metals. In order to counteract these problems, there have been many efforts to obtain dense coatings by spraying under low pressure or vacuum and by controlling particle size and morphology of the spraying materials. The aim of the present study is to survey the effects of the HIP treatment between 1100 and 130$0^{\circ}C$ on plasma-sprayed oxide coating of A1$_2$O$_3$, A1$_2$O$_3$-SiO$_2$ on the metal substrate (type C18N10T stainless steel). These effects were characterized by phase identification, Vickers hardness measurement, and tensile test before and after HIPing, These results show that high-pressure treatment has an advantage for improving adhesive strength and Vickers hardness of plasma- sprayed coatings.

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용사법에 의해 제조된 Al/SiC 복합재료의 마모거동 (1) - 미끄럼 속도의 영향 - (Wear Behavior of Al/SiC Composites Fabricated by Thermal Spray Process (1) - Effect of Sliding Speed on Wear Behavior -)

  • 이광진;김균택;김영식
    • Tribology and Lubricants
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    • 제27권6호
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    • pp.351-355
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    • 2011
  • Al/SiC composites were fabricated by thermal spray process, and the dry sliding wear tests were performed using the various sliding speed of 10, 30, 60 and 90 RPM through 1000 cycles. The applied load was 10 N and radius of wear track was 15 mm. Wear tracks on the Al/SiC composites were investigated using scanning electron microscope(SEM) and energy dispersive X-ray spectroscopy (EDS). In the case of sliding speed of 10 RPM, adhesive wear behavior caused by plastic deformation of composits surface was observed. In the cases of sliding speed of 30, 60, 90 RPM, abrasive wear behavior on the adhered layer formed by debris were observed. Through this study, it was found that the wear behavior of Al/SiC composites was mainly influenced by the sliding speed.

이동형 핵종 분석 장치용 CZT 반도체 검출기의 완충전극에 대한 연구 (A Study of Interface Layer on CdZnTe Radiation Sensor for Potable Isotope Identifier)

  • 조윤호;박세환;김용균;하장호
    • 방사선산업학회지
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    • 제5권1호
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    • pp.95-99
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    • 2011
  • The electrical and mechanical properties of electrode for radiation detection are very important. In general, Au electrode and CZT crystal are combined to form ohmic contacts, and the best energy resolution is shown at the Au electrode. The metal contacts are fabricated by electroless deposition method, sputtering deposition method and thermal evaporation method. The electrode fabrication is easy with use of the thermal evaporation method, while an adhesive strength is weak. Thus interface materials such as Ag, Al and Ni were investigated to overcome defects generated by the this method. The thickness of the interface material between the Au electrode and the CZT crystal was 100 Angstroms, the Au electrode with thickness of 400 Angstroms was deposited. The Al+Au electrode is shown that the results of current-voltage and radiation response are similar to results of Au electrode.

Analysis of Ni/Cu Metallization to Investigate an Adhesive Front Contact for Crystalline-Silicon Solar Cells

  • Lee, Sang Hee;Rehman, Atteq ur;Shin, Eun Gu;Lee, Doo Won;Lee, Soo Hong
    • Journal of the Optical Society of Korea
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    • 제19권3호
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    • pp.217-221
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    • 2015
  • Developing a metallization that has low cost and high efficiency is essential in solar-cell industries, to replace expensive silver-based metallization. Ni/Cu two-step metallization is one way to reduce the cost of solar cells, because the price of copper is about 100 times less than that of silver. Alkaline electroless plating was used for depositing nickel seed layers on the front electrode area. Prior to the nickel deposition process, 2% HF solution was used to remove native oxide, which disturbs uniform nickel plating. In the subsequent step, a nickel sintering process was carried out in $N_2$ gas atmosphere; however, copper was plated by light-induced plating (LIP). Plated nickel has different properties under different bath conditions because nickel electroless plating is a completely chemical process. In this paper, plating bath conditions such as pH and temperature were varied, and the metal layer's structure was analyzed to investigate the adhesion of Ni/Cu metallization. Average adhesion values in the range of 0.2-0.49 N/mm were achieved for samples with no nickel sintering process.

Studying the effects of CFRP and GFRP sheets on the strengthening of self-compacting RC girders

  • Mazloom, Moosa;Mehrvand, Morteza;Pourhaji, Pardis;Savaripour, Azim
    • Structural Monitoring and Maintenance
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    • 제6권1호
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    • pp.47-66
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    • 2019
  • One method of retrofitting concrete structures is to use fiber reinforced polymers (FRP). In this research, the shear, torsional and flexural strengthening of self-compacting reinforced concrete (RC) girders are fulfilled with glass fiber reinforced polymer (GFRP) and carbon fiber reinforced polymer (CFRP) materials. At first, for verification, the experimental results were compared with numerical modeling results obtained from ABAQUS software version 6.10. Then the reinforcing sheets were attached to concrete girders in one and two layers. Studying numerical results obtained from ABAQUS software showed that the girders stiffness decreased with the propagations of cracks in them, and then the extra stresses were tolerated by adhesive layers and GFRP and CFRP sheets, which resulted in increasing the bearing capacity of the studied girders. In fact, shear, torsion and bending strengths of the girders increased by reinforcing girders with adding GFRP and CFRP sheets. The samples including two layers of CFRP had the maximum efficiencies that were 90, 76 and 60 percent of improvement in shear, torsion and bending strengths, respectively. It is worth noting that the bearing capacity of concrete girders with adding one layer of CFRP was slightly higher than the ones having two layers of GFRP in all circumstances; therefore, despite the lower initial cost of GFRP, using CFRP can be more economical in some conditions.

Analysis on an improved resistance tuning type multi-frequency piezoelectric spherical transducer

  • Qin, Lei;Wang, Jianjun;Liu, Donghuan;Tang, Lihua;Song, Gangbing
    • Smart Structures and Systems
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    • 제24권4호
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    • pp.435-446
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    • 2019
  • The existing piezoelectric spherical transducers with fixed prescribed dynamic characteristics limit their application in scenarios with multi-frequency or frequency variation requirement. To address this issue, this work proposes an improved design of piezoelectric spherical transducers using the resistance tuning method. Two piezoceramic shells are the functional elements with one for actuation and the other for tuning through the variation of load resistance. The theoretical model of the proposed design is given based on our previous work. The effects of the resistance, the middle surface radius and the thickness of the epoxy adhesive layer on the dynamic characteristics of the transducer are explored by numerical analysis. The numerical results show that the multi-frequency characteristics of the transducer can be obtained by tuning the resistance, and its electromechanical coupling coefficient can be optimized by a matching resistance. The proposed design and derived theoretical solution are validated by comparing with the literature given special examples as well as an experimental study. The present study demonstrates the feasibility of using the proposed design to realize the multi-frequency characteristics, which is helpful to improve the performance of piezoelectric spherical transducers used in underwater acoustic detection, hydrophones, and the spherical smart aggregate (SSA) used in civil structural health monitoring, enhancing their operation at the multiple working frequencies to meet different application requirements.