• 한국재료학회지
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• 제20권4호
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• pp.187-193
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• 2010

Chromium nitride (CrN) samples with two different layer structures (multilayer and single layer) were coated on bipolar plates of polymer electrolyte membrane fuel cells (PEMFC) using the reactive sputtering method. The effects with respect to layer structure on corrosion resistance and overall cell performance were investigated. A continuous and thin chromium nitride layer ($Cr_{0.48}\;N_{0.52}$) was formed on the surface of the SUS 316L when the nitrogen flow rate was 10 sccm. The electrochemical stability of the coated layers was examined using the potentiodynamic and potentiostatic methods in the simulated corrosive circumstances of the PEMFC under $80^{\circ}C$. Interfacial contact resistance (ICR) between the CrN coated sample and the gas diffusion layer was measured by using Wang's method. A single cell performance test was also conducted. The test results showed that CrN coated SUS316L with multilayer structure had excellent corrosion resistance compared to single layer structures and single cell performance results with $25\;cm^2$ in effective area also showed the same tendency. The difference of the electrochemical properties between the single and multilayer samples was attributed to the Cr interlayer layer, which improved the corrosion resistance. Because the coating layer was damaged by pinholes, the Cr layer prevented the penetration of corrosive media into the substrate. Therefore, the CrN with a multilayer structure is an effective coating method to increase the corrosion resistance and to decrease the ICR for metallic bipolar plates in PEMFC.

• 센서학회지
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• 제22권5호
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• pp.315-320
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• 2013

In this paper, the properties of strain sensors made of spin-capable multi-walled carbon nanotubes (MWCNTs) were characterized and their sensing mechanisms analyzed. The key contribution of this paper is a new fabrication technique that introduces a simpler transfer method compared to spin-coating or dispersion CNT. Resistance of the MWCNT sheet strain sensor increased linearly with higher strain. To investigate the effect of CNT concentration on sensitivity, two strain sensors with different layer numbers of MWCNT sheets (one and three layers) were fabricated. According to the results, the sensor with a three-layer sheet showed higher sensitivity than that with one layer. In addition, experiments were conducted to examine the effects of environmental factors, temperature, and gas on sensor sensitivity. An increase in temperature resulted in a reduction in sensor sensitivity. It was also observed that ambient gas influenced the properties of the MWCNT sheet due to charge transfer. Experimental results showed that there was a linear change in resistance in response to strain, and the resistance of the sensor fully recovered to its unstressed state and exhibited stable electromechanical properties.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.146-149
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• 2004

Porous silicon(PS) as an excellent light diffuser can be used as an antireflection layer without other antireflection coating(ARC) materials. PS layers were obtained by electrochemical etching(ECE) anodization of silicon wafers in hydrofluoric acid/ethanol/de-ionized(DI) water solution($HF/EtOH/H_2O$). This technique is based on the selective removal of Si atoms from the sample surface forming a layer of PS with adjustable optical, electrical, and mechanical properties. A PS layer with optimal ARC characteristics was obtained in charge density (Q) of 5.2 $C/cm^2$. The weighted reflectance is reduced from 33 % to 4 % in the wavelength between 400 and 1000 nm. The weighted reflectance with optimized PS layers is much less than that obtained with a commercial SiNx ARC on a potassium hydroxide(KOH) pre-textured multi-crystalline silicon(mc-Si) surface.

• 한국생산제조학회지
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• 제9권1호
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• pp.96-101
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• 2000

Ceramic, PCD and CBN tools are available for the difficult-to-cut-materials such as hardened carbon tool steel, stainless steel, Inconel 718 and etc.. Ceramic toolsare likely to be chipped and abruptly broken before the appearance of normal wear in turning. Ther2efore ceramic tools are suitable for continuous cut in turning not for intermittent in milling. In this study, TiN/TiCN multi-layer coated ceramic tools were found to restrain the chipping, breaking and early fracture and to increase the critical cutting speed owing to TiN/TiCN multi-layer coating in Arc Ion Plating of PVD method.

• 한국전기전자재료학회논문지
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• 제20권11호
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• pp.991-994
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• 2007

In this paper, we have designed the anti-reflection(AR) coating for $1400{\sim}1600$ nm wavelength range on the ferrule facet of optical connector. The low-temperature ion-assisted deposition was applied to AR coating on the ferrule facet in order to avoid damage of optical connector. We have measured the refractive index of coating film($Ta_2O_5\;and\;SiO_2$) using the ellipsometer and optimized the film thickness using the SEM and thickness measurement equipment. UV-VIS-NIR spectrophotometer is used to measure transmissivity of the AR coated ferrule facet. The refractive index of $Ta_2O_5\;and\;SiO_2$ is $2.123{\sim}2.125$ and $1.44{\sim}1.442$, respectively, for $1400{\sim}1600$ nm wavelength range. The transmissivity of the AR coated ferule facet is more than 99.8 % for $1425{\sim}1575$ nm wavelength range and more than 99.5 % for $1400{\sim}1600$ nm wavelength range. The return loss of the AR coated ferrule facet is 30.1 dB.

• 펄프종이기술
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• 제44권5호
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• pp.32-38
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• 2012

This study was carried out to elucidate the potential in substitution of SB latex with eco-friendly starch based bio-binder as a coating binder. The part of SB latex in coating color of pre- and top layer was substituted with starch based bio-binder in order to evaluate the characteristics of coating color and coated paper, and printability. The viscosity and water retention of coating color were increased by substitution of SB latex with starch based bio-binder. Roughness of coated paper was increased by substitution with starch based bio-binder, although there was not significant changes in roughness when SB latex is used as a binder in pre-coating color. Brightness and whiteness of coated paper were not affected, but opacity and print mottle were improved by substitution with starch based bio-binder. The interesting result observed was that dry-pick did not affected significantly, and ink set-off was improved by starch based bio-binder. It is expected that starch based bio-binder can be commercialized if the systematic further research works are carried out.

• 공업화학
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• 제19권1호
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• pp.37-44
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• 2008

저렴한 비용으로 도전성 투명 필름을 제조하기 위해 PET 필름 위에 습식 도포법으로 ITO/ATO 막을 적층시켰다. 압력 15 MPa, 온도 $50^{\circ}C$의 SAS 합성 조건으로 ITO를 합성하였으며 ITO의 최적 조성비(In/Sn)는 65, 합성된 ITO의 평균입경은 $15{\pm}2nm$, 표면저항 값은 $4{\times}10^4{\Omega}{\cdot}cm$였다. 도포액은 pH 10에서 제조하였으며 ATO 막의 표면조도(Ra), 표면저항 값, 빛투과율은 각각 9 nm, $5.5{\times}10^6{\Omega}{\cdot}cm$, 91%였다. 일차 도포된 ATO 막 위에 0.1, 0.5, 1.0, 2.0 ITO wt% 첨가한 도포액으로 ITO 막을 적층 제조하였으며, ITO/ATO 적층 필름의 표면조도는 4, 10, 12, 16 nm이였으며 표면저항 값은 각각 $3.7{\times}10^6$, $2.4{\times}10^6$, $8{\times}10^5$, $2{\times}10^5{\Omega}{\cdot}cm$로 측정되었다. 적층 필름의 빛투과율은 각각 89, 88, 86, 82%이였으며 ITO 농도가 높아질수록 빛투과율은 낮아졌다.

• 한국식품과학회지
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• 제31권3호
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• pp.771-777
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• 1999

CSLM 기술을 이용하여 Salmonella enteritidis에 의한 계란 오염 과정을 관찰하여 난막의 3중막 구조, cuticle 층 그리고 5가지 필름 피복의 침투 방어효과를 조사하였다. 난막을 구성하는 fiber의 지름은 각각 outer membrane $1.5{\sim}7.2\;{\mu}m$, inner membrane $0.8{\sim}2.0\;{\mu}m$이었고, limiting membrane을 구성하는 입자의 지름은 $0.1{\sim}1.4\;{\mu}m$이었으며, 두께는 각각 평균 10.0, 3.5, $3.6\;{\mu}m$이었다. 난각과 접해 있는 outer membrane은 다음 층인 inner membrane과 부분적으로 중첩되어있고, limiting membrane의 입자들은 매우 밀집되어 inner membrane과 중첩된 상태로 존재하였다. Cuticle층은 전체 계란 표면적 중 $40{\sim}80%$ 를 덮고 있었으며, 두께는 평균 $6.0\;{\mu}m$이었고 피복 필름들의 평균 두께는 자각 mineral oil $5.0\;{\mu}m$, dextrin $3.6\;{\mu}m$, gelatin $3.9\;{\mu}m$, starch $2.5\;{\mu}m$, chitosan $2.2\;{\mu}m$이었다. 필름 피복에 의한 Salmonella enteritidis 생육 억제효과를 관찰한 결과, chitosan이 가장 효과적이었다. 그리고 trisodium phosphate (TSP), cetylpyridinium chloride (CPC) 처리, 5종의 필름 피복 처리와 무처리한 계란표면에 Salmonella enteritidis를 접종한 후 내부 전이 과정을 CSLM을 이용하여 다색영상화(multi-color imaging)와 시간당 투과 균수에 대한 plate count로 비교한 결과, 난각이나 3중막 구조의 난막보다는 cuticle 층이 Salmonella균의 오염을 차단하는데 결정적인 역할을 하는 것으로 나타났으며, chitosan 피복이 cuticle 층과 비슷한 효과를 보였다. 따라서 피복 필름중에서 chitosan이 최외부 방어막인 cuticle층이 결손된 난각 부위를 피복하는데 가장 적합할 것으로 사료된다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2000년도 추계학술대회논문집
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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 modulus. 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.

• 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.