• Korean Journal of Materials Research
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• v.25 no.8
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• pp.391-397
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• 2015

NiO catalysts/$Al_2O_3$/FeCrAl alloy foam for hydrogen production was prepared using atomic layer deposition (ALD) and subsequent dip-coating methods. FeCrAl alloy foam and $Al_2O_3$ inter-layer were used as catalyst supports. To improve the dispersion and stability of NiO catalysts, an $Al_2O_3$ inter-layer was introduced and their thickness was systematically controlled to 0, 20, 50 and 80 nm using an ALD technique. The structural, chemical bonding and morphological properties (including dispersion) of the NiO catalysts/$Al_2O_3$/FeCrAl alloy foam were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy and scanning electron microscopy-energy dispersive spectroscopy. In particular, to evaluate the stability of the NiO catalysts grown on $Al_2O_3$/FeCrAl alloy foam, chronoamperometry tests were performed and then the ingredient amounts of electrolytes were analyzed via inductively coupled plasma spectrometer. We found that the introduction of $Al_2O_3$ inter-layer improved the dispersion and stability of the NiO catalysts on the supports. Thus, when an $Al_2O_3$ inter-layer with a 80 nm thickness was grown between the FeCrAl alloy foam and the NiO catalysts, it indicated improved dispersion and stability of the NiO catalysts compared to the other samples. The performance improvement can be explained by optimum thickness of $Al_2O_3$ inter-layer resulting from the role of a passivation layer.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.15-18
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• 2003

Pentacene OTFTs of $Al_2O_3$ insulator treated with a diluted PMMA were fabricated for the application of the low voltage operation and large area displays. The operation voltage of 15 V and the mobility of 0.35 $cm^2/Vsec$ are obtained even adopting the thick dielectric of 100 nm which was deposited by atomic layer deposition at the temperature of $150^{\circ}C$. The current on-off ratio was $4.1{\times}10^4$ for the OTFTs treated with 9:1 PMMA and good saturation characteristics were obtained as drain voltage increases.

• Journal of the Korean institute of surface engineering
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• v.20 no.2
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• pp.49-59
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• 1987

The properties of $Cr_2O_3-Al_2O_3-SiO_2$ composite oxide coatings on steel surface were investigated. The results obtained were as follows: The microhardness of oxide coating layer increased with increasing heat-treatment temperature and $Cr_2O_3$ content in coating layer. The hardness showed the highest value (850Hv) treated at 700$^{\circ}C$ for $SiO_2:Al_2O_3:Cr_2O_3$=1:1:4. Increasing heat-treatment temperature, corrosion current density became lower and coating layer became denser. The corrosion current density showed the lowest value $(6.5{\times}10^{-5}\;Acm^2)$ treated at 750$^{\circ}C\;for\;SiO_2:Al_2O_3:Cr_2O_3$=1:1:3. These results were explained by protective layer which was formed during heat-treatment. The bonding between matrix and coating layer is expected to be made mechanically and chemically by the inter diffusion of Ni and Fe. The composite oxide coating was formed by softening of the binder with increasing heat-treatment temperature. The strengthening of coating layer is to be resulted from the dispersion of major oxide particles.

• Nuclear Engineering and Technology
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• v.52 no.10
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• pp.2299-2305
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• 2020

Zr alloy specimens were coated with Cr-Al alloy to enhance their resistance to oxidation. The coated samples were oxidized at 1200 ℃ in a steam environment for 300 s and showed extremely low oxidation when compared to uncoated Zr alloy specimens. The microstructure and elemental distribution of the oxides formed on the surface of Cr-Al alloys have been investigated by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). A very thin protective layer of Cr₂O₃ formed on the outer surface of the Cr-Al alloy, and a thin Al₂O₃ layer was also observed in the Cr-Al alloy matrix, near the surface. Our results suggest that these two oxide layers near the surface confers excellent oxidation resistance to the Cr-Al alloy. Even after exposure to a high temperature of 1200 ℃, inter-diffusion between the Cr-Al alloy and the Zr alloy occurred in very few regions near the interface. Analysis of the inter-diffusion layer by high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (EDS) measurement confirmed its identity as Cr₂Zr.

• Journal of the Korean institute of surface engineering
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• v.33 no.1
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• pp.17-24
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• 2000

The microstructures and corrosion properties of Al-Si diffusion coated PWA1426 and PWA658 alloys have been investigated. The coated layer and corrosion properties were analysed by SEM, EDS and hot corrosion test. According to the results of SEM, it is supposed that the coated layers were composed of mixed, denuded and inter-diffusion layer. The coated PWA1426 alloy improved corrosion properties, compared to the PWA658 alloy. Corrosion debris generated during hot corrosion test of PWA658 alloy are identified as NiO, $TiO_2$and $NiAl_2$$O_4$from coated layer which increase oxidation rate and decrease adhesion. The PWA1426 alloy heat treated at $1080^{\circ}C$ showed that NiAl and $Al_2$$O_3$formed on coated layer.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.5 no.2
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• pp.122-128
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• 1995

Sintered bodies were prepared from ${\alpha} - Al_2O_3/SiO_2$ composite powders which each alumina particles were surrounded by silica particles and investigated the mullitization behavior on the process of reaction - sintering. Mullitized reaction was started by formation of amorphous aluminosilicate inter - layer and proceeded by diffusion of alumina through this inter-layer. The growth of mullite was happened along the surface of alumina and controlled by the rate of diffusion.

• Analytical Science and Technology
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• v.17 no.4
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• pp.355-362
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• 2004

Fission products and Inter reaction layer of $U_3Si-Al$ dispersion fuel, irradiated in HANARO research reactor with 121 kW/m of maximum liner power and 63 at% of average burn-up, was characterization by EPMA (Electron Probe Micro Analyzer). The fuel punching system developed by Irradiated Materials Examination Facility (IMEF) has used to make these samples for the EPMA. With this system a very small and thin specimen which is 1.57 mm in diameter and 2 mm in thickness respectively has been fabricated to protect the EPMA operator from high radioactive fuel and to mini-mize the equivalent dose rate less than 150 mSv/h. EPMA was performed to observe layers of sectional, Inter-reaction and oxide with specimens of cutting and polished. Stoichiometry in the Inter-reaction layer with $16{\mu}m$ of thickness was $U_{2.84}$ Si $Al_{14}$ with calibration of $UO_2$ and $U_{3.24}$ Si $Al_{14.1}$ with calibration of standard specimen. metallic precipitates in this layer were not observed using fission products examination.

• Journal of the Semiconductor & Display Technology
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• v.10 no.1
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• pp.27-32
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• 2011

In this study, we have investigated the power conversion efficiency of organic solar cells utilizing conjugated polymer/fullerene bulk-hetero junction(BHJ) device structures. We have fabricated poly(3-hexylthiophene)(P3HT), poly[2methoxy-5-(3',7'-dimethyloctyl-oxy)-1-4-phenylenevinylene] as an electron donor, [6,6]-phenyl $C_{61}$ butyric acid methylester(PCBM-$C_{61}$)as an electron acceptor, and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)(PEDOT:PSS) used as a hole injection layer(HIL), after fabricated active layer, between active layer and metal cathode(Al) deposited LiF interlayer(5 nm). The properties of fabricated organic solar cell(OSC) devices have been analyzed as a function of different thickness. The electrical characteristics of the fabricated devices were investigated by means J-V, fill factor(FF) and power conversion efficiency(PCE). We observed the highest PCEs of 0.628%(MDMO-PPV:PCBM-$C_{61}$) and 2.3%(P3HT:PCBM-$C_{61}$) with LiF inter-layer at the highest thick active layer, which is 1.3times better than the device without LiF inter-layer.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.1
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• pp.149-157
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• 2012

Experiments for As(V) removal using synthesized $Ca{\cdot}Al$-monosulfate was performed from the water contaminated with arsenate. Monosulfate is known as LDHs (Layered Double Hydroxides) which is one of the anionic clay minerals. Monosulfate was synthesized mixing $C_3A$ (tricalcium aluminate), gypsum (calcium sulfate), and water with an intercalation method. The product form the synthesis was characterized by FE-SEM, WDXRF, PXRD, and FT-IR. Experiments with different doses of monosulfate were carried out for kinetic. As a result of experiment, the concentration of As(V) was reduced from 0.67 mM to 0.19 mM (0.67mM of monosulfate) and 0.178 mM (1.34 mM of monosulfate). The concentration of sulfate was increased with As(V) decrease. The result of PXRD showed that the d-spacing of inter layer ($d_{003}$ peak) was shifted from 8.927 ${\AA}$ to 8.095 ${\AA}$ because the sulfate in the inter layer of monosulfate was exchanged arsenate with water molecules bonded. From the FT-IR results, a new single band (800 cm-1) was observed after the reaction of monosulfate and As(V). The arsenic removal can be regarded as anion exchange mechanism that is one of the characteristics of LDHs from the results of PXRD and FT-IR analysis.

• Transactions on Electrical and Electronic Materials
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• v.11 no.1
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• pp.11-14
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• 2010

The interaction of -$Al(CH_3)_2$ with -OH on a fully OH-terminated Si (001) surface was studied using density functional theory. Two sites for $Al(CH_3)_3$ to react with the -OH on the surface were identified. The $-Al(CH_3)_2$ product energetically favored the dimer-row site rather than the inter-row site because the Al atom of $-Al(CH_3)_2$ at the dimer-row site was attracted by the lone pair electrons of the O atom in the neighboring -OH. The energy barrier for the transfer of the $-Al(CH_3)_2$ between the two sites was 0.11 eV, and therefore, the $-Al(CH_3)_2$ at the inter-row site can easily transfer to the dimer-row site at room temperature.