• Korean Membrane Journal
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• 제7권1호
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• pp.19-27
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• 2005

PP hollow fiber membrane was hydrophilized by EVOH dip coating followed by low temperature plasma treatment and UV irradiation. EVOH coating attained high water flux without any prewetting but its stability did not guaranteed at high water permeation rate. At high water permeation rate, water flux declined gradually due to swelling and delamination of the EVOH coating layer causing pore blocking effect. However, plasma treatment reduces the swelling, which suppress delamination of the EVOH coating layer from PP support result in relieving the flux decline. Also, UV irradiation helped the crosslinking of the EVOH coating layer to enhance the performance at low water permeation rate. FT-IR and ESCA analyses reveal that EVOH dip coating performed homogeneously through not only membrane surface but also matrix. Thermogram of EVOH film modified plasma treatment and W irradiation show that crosslinking density of EVOH layer increased. Chemical modification by plasma treatment and UV irradiation stabilized the hydrophilic coating layer to increase the critical flux of the submerged membrane.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2013년도 춘계학술대회 논문집
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• pp.121-121
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• 2013

수소로 희석된 벤젠 가스를 반응 가스로 이용하여 합성된 DLC 박막의 마찰 마모 특성을 평가하기 위하여, 일반 대기 환경 및 수중 환경에서 마모 실험을 수행하였다. 일반 대기 환경에서는 박막의 기계적 특성, 마찰 계수 및 마모 거동이 거의 변화하지 않았다. 반면, 수중 환경에서는 마찰 계수가 대기 환경에서보다 안정적으로 평가되었다. 이는 DI-water가 윤활제(lubricant) 역할을 하기 때문으로 예측된다. 또, 수중 환경에서의 마모 실험 결과, 수소가 희석되지 않은 반응 가스를 이용하여 증착 된 DLC 박막의 경우, delamination wear가 상대적으로 많이 관찰되었다. 하지만, 반응 가스에 희석 된 수소량이 증가함에 따라서, 이런 delamination wear가 현저하게 억제됨을 관찰하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.698-703
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• 2004

In this study, mode I interlaminar fracture phenomena of carbon fabric/epoxy composite for tilting train were investigated. Specimens were 25mm $\times$ 180mm $\times$ 4.7mm with an initial artificial delamination of 65mm at one end. This delamination with the thickness of 12.5$\mu$m and 25$\mu$m (teflon film) was used. Mode I interlaminar fracture toughness was measured using the double cantilever beam and the fractured surfaces were examined through a scanning electron microscope. The experimental results obtained in this study would be applicable in the design and structural analysis of the composite structures.

• Composites Research
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• 제29권4호
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• pp.203-208
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• 2016

금속/고분자 샌드위치 복합재는 경량성과 제진, 방음 등의 다기능성의 측면에서 기존의 스틸 강판을 대체할 후보 중 하나로서 연구되고 있다. 금속/고분자 복합재의 활용하기 위해서는 접착력을 바탕으로 한 박리 거동 예측이 매우 중요한 요소이다. 본 연구에서는 응집요소를 사용하여 유한요소 해석을 통해 접착제를 사용한 고분자 테이프의 박리거동 해석을 수행하였다. 응집요소의 특성은 박리시험과 역학 관계로부터 도출한 파괴인성을 통해 정의하였고 이를 해석에 적용하였다. 스틸 강판에서 고분자 테이프를 박리하는 시험을 모사하였고, 해석결과와 시험결과를 비교하여 박리 거동 모사가 가능함을 확인하였다.

• 한국광학회지
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• 제26권5호
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• pp.261-264
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• 2015

본 논문에서는 인쇄회로기판의 감광층 보호필름을 532 nm 파장의 나노초 레이저의 단일펄스로 박리할 수 있음을 보여준다. 인쇄회로기판의 가장자리를 9 mm 크기의 레이저 빔으로 국부적으로 박리시킨 후 스카치테이프를 레이저 조사에 의해 초기 박리 된 영역에 붙여 전체 보호필름을 떼어내었는데, 160 - 170 mJ의 펄스에너지 범위에서는 10회의 반복된 실험 모두에서 감광층 손상 없는 박리에 성공하였다. 보호필름 초기 박리에 레이저를 사용하는 방식은 기계적 압착에 바탕을 둔 기존의 널링방식과는 달리 감광층에 손상을 유발하지 않는 비접촉 방식으로써, 인쇄회로기판 제조공정에 보다 효율적으로 사용될 수 있을 것으로 판단된다.

• 한국표면공학회지
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• 제29권2호
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• pp.93-99
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• 1996

In this work BN thin films were deposited on Si substrate by R. F. sputtering method at $200^{\circ}C$ and in Ar + $N_2$ mixed gas atmosphere. In order to investigate the effect of ion bombardment on substrate for c-BN bonding, substrate bias voltage was applied. The optimum substrate bias voltage for c-BN bonding was determined by FTIR analysis on specimens which were deposited with various bias voltages. Then BN thin film was deposited with this optimum condition and its phase, morphology, chemical composition, and refractive index were compared with those of BN film which was deposited without bias voltage. FTIR results showed that BN films deposited with substrate bias voltage were composed of mixed phases of c-BN and h-BN, while those deposited without bias voltage were h-BN only. When pure Ar gas was used for sputtering gas, BN films were delaminated easily from substrate in air, while when 10% $N_2$ gas was added to the sputtering gas, although c-BN specific infrared peak was reduced, delamination did not occur. GXRD and TEM results showed that BN films were amorphous phases regardless of substrate bias voltage, and AES results showed that the chemical compositions of B/N were about 1.7~1.8. The refractive index of BN film deposited with bias voltage was higher than that without bias voltage. The reason is believed to be the existence of c-BN bonding in BN film and the higher density of film that deposited with the substrate bias voltage.

• International Journal of Ocean System Engineering
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• 제2권2호
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• pp.106-115
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• 2012

In the present study, TiN and CrN films were coated by arc ion plating equipment onto aluminum alloy substrate, A2024. The film thickness was about 4.65 ${\mu}m$. TiN and CrN films were analyzed by X-ray diffraction and energy dispersive X-ray equipments. The Young's modulus and the micro-Vickers hardness of aluminum substrate were modified by the ceramic film coatings. The difference in Young's modulus between substrate and coating film would affect on the wear resistance. The critical load, Lc, was 75.8 N for TiN and 85.5 N for CrN. It indicated from the observation of optical micrographs for TiN and CrN films that lots of cracks widely propagated toward the both sides of scratch track in the early stage of MODE I. TiN film began to delaminate completely at MODE II stage. The substrate was finally glittered at MODE III stage. For CrN film, a few crack can be observed at MODE I stage. The delamination of film was not still occurred at MODE II and then was happened at MODE III. This agrees with critical load measurement which the adhesive strength was greater for CrN film than for TiN film. Consequently, it was difficult for CrN to delaminate because the adhesive strength was excellent against Al substrate. The wear process, which the film adheres and the ball transfers, could be enhanced because of the increase in loading. The wear weight of ball was less for CrN than for TiN. This means that the wear damage of ball was greater for TiN than for CrN film. It is also obvious that it was difficult to delaminate because the CrN coating film has high toughness. The coefficient of friction was less for CrN coating film than for TiN film.

• Composites Research
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• 제17권6호
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• pp.14-21
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• 2004

본 연구에서는 몇 가지 접합 방법에 따라 일방향 복합재료 단일 겹치기 접합 조인트의 파손 과정, 모드 및 강도를 실험적으로 평가하였다 접합 방법으로는 접착제 없는 동시성형, 접착제를 사용한 동시성형 및 이차 접합의 세 가지를 고려하였다 또한 이차 접합 조인트에서 몇 가지 파라미터의 영향도 살펴보았다. 접착제 없는 동시성형 시편은 가장 우수한 조인트 강도를 나타내었다. 이차접합 조인트에서는 접착제 층의 점진적인 파손이 발생하였다. 접착제의 재료 및 접합 강도가 상대적으로 강한 필름 접착제의 동시성형 조인트는 갑작스런 층간분리 파손이 발생하였으며 이차 접합 조인트보다 더 낮은 파손 강도를 나타내었다. 이차 집합 조인트에서 층간분리 파손이 발생하지 않은 것은 접착제 층에서의 균열 진전 및 점진적 파손이 층간분리 파손을 방지한 것으로 보인다. 따라서 복합재료 접합 조인트의 파손 강도는 접착제의 재료 강도 또는 접착 성능과 항상 비례하지 않으며 이것은 복합재료가 층간 분리 파손에 약하기 때문이다.

• 대한금속재료학회지
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• 제47권6호
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• pp.372-377
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• 2009

We report on hysteresis behavior in the electrical resistance-hydrogen concentration of Pd thin films. The variation of the electrical resistance has been investigated during the process of absorption and desorption of hydrogen gas ($H_{2}$) as a function of thickness of Pd thin films. The hysteresis behavior in the electrical resistance with $H_{2}$ concentration was found for Pd thin films and consists of $\alpha$ phase, ${\alpha}+{\beta}$ phase, and $\beta$ phase regions. The sensitivity of Pd thin films with $H_{2}$ concentration was found to follow Sieverts' law in the $\alpha$ phase region. However, the sensitivity was observed to increase abruptly with $H_{2}$ concentration in the ${\alpha}+{\beta}$ phase co-exist region. This is because Pd-H interaction is stronger in the $\beta$ phase than in the $\alpha$ phase and needs a higher concentration gradient as a driving force to desorb. The formation of the $\beta$ phase also was observed to cause the structural change because of the lattice expansion during absorption. The hysteresis height and the trace of structural change were affected by the thickness of the Pd film. As the film becomes thinner, the hysteresis height becomes lower and the amount of delamination on the surface becomes smaller. For films thinner than 20 nm in thickness, the delamination was not found but electrical resistance hysteresis was still observed.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.283.1-283.1
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• 2016

Tin Oxide(SnO2) has been widely investigated as a transparent conducting oxide (TCO) and can be used in optoelectronic devices such as solar cell and flat-panel displays. It would be applicable to fabricating the wide bandgap semiconductor because of its bandgap of 3.6 eV. In addition, SnO2 is commonly used as gas sensors. To fabricate high quality epitaxial SnO2 thin films, a powder sputtering method was used, in contrast to typical sputtering technique with sintered target. Single crystalline sapphire(0001) substrates were used. The samples were prepared with varying the growth parameters such as gas environment and film thickness. Then, the samples were characterized by using X-ray diffraction, scanning electron microscopy, and atomic force microscopy measurements. We found that the strain evolution of the samples was highly affected by gas environment and growth rate, resulted in the delamination under O2 environment.