• Journal of the Korean Society of Safety
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• v.21 no.1 s.73
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• pp.79-85
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• 2006

Olefinic compatibilized blend(R-PP/R-PE)/layered silicate composites have been prepared by melt intercalation technique directed from $Na^{+}$ montmorillonite(MMT) or organophilic montmorillonites while using magnesium hydroxide as flame retardant. Morphology and flammability properties were characterized by X-ray diffraction(XRD), transmission electron microscopy(TEM), scanning electron microscopy(SEM), thermogravimetry analysis(TGA), limiting oxygen index(LOI), UL94 test. It is found that the compatibilized blend/layered silicate(Cloisite 20A) nanocomposites have a mixed immiscible-intercalated structure and there is better intercalation when a compatibilizer is combined with the polymer and layered silicate to be melt blended. A very large increase in the LOI value was observed with hybrid filler addition and further enhancement in thermal stability and compatibility of blend was obtained for the compatibilized blend containing small amount of layered silicate.

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3730-3734
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• 2010

A simple, inexpensive and less time consuming electrochemical methods were carried out to prepare ordered mesoporous cobalt films. Ordered mesoporous cobalt films were successfully synthesized by templated electrodepostion of hexagonal $H_1$-e Co ion. The electrodeposited mesopores films were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), low angle X-ray diffraction (XRD) and voltammetric methods. The applicability of thin films as high - performance super capacitors electrode materials is demonstrated electrochemically using cyclic voltammetry (CV) technique.

• Journal of the Korean Ceramic Society
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• v.49 no.6
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• pp.511-517
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• 2012

Pd/MWCNT/$TiO_2$ composites were synthesized by a sol-gel technique using multi-walled carbon nanotubes (MWCNT), palladium (II) chlorite ($PdCl_2$) and titanium tetrachloride ($TiCl_4$) as the carbon, palladium and titanium precursors. The Pd/MWCNT/$TiO_2$ composites prepared were characterized by BET surface area measurements, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The photocatalytic activity of the composites was evaluated using the degradation of methylene blue (MB) under UV and visible light irradiation as a model.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2008.11a
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• pp.9-10
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• 2008

Triple layers structure of $SiO_2$/ZnS:Mn/ZnS was synthesized by using ion substitution and chemical precipitation method. Each layer thickness was controlled by adjusting the concentration of manganese (II) acetate ($Mn(CH_3COO)_2$) and tetraethyl orthosilicate (TEOS). The structure and morphology of prepared phosphors were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron probe microscopic analyzer (EPMA). Photoluminescence (PL) properties of ZnS with different layer thickness and amount of Mn activator were analyzed by PL spectrometer. PL emission intensity and PL stability were analyzed for evaluating effects of Mn activator.

• Bulletin of the Korean Chemical Society
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• v.11 no.5
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• pp.379-383
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• 1990

$YBa_2Cu_{3-x}Ni_xO_{7-{\delta}}$, with x = 0.05, 0.2, 0.4, 0.7 and 1.0 had been prepared by the thermal decomposition of corresponding nitrates. Among them, the sample with x = 0.05 shows above-liquid-$N_2$ temperature superconductivity with $T_c$ of 88.7K. According to the X-ray diffraction analysis, its crystal symmetry was estimated as orthorhombic with the lattice parameters of a = 3.866${\AA}$, b = 3.893${\AA}$, c = 11.715${\AA}$. The chemical composition of the sample was determined by electron probe microanalysis and the chemical composition around its grain boundaries was carefully studied by the X-ray line scanning technique. From the observed binding energy of Ni-$2p_{3/2}$ orbital electron (B.E. = 853 eV) measured by X-ray photoelectron spectroscopy, the valency state of nickel stabilized in $YBa_2Cu_{2.95}Ni_{0.05}O_{7-{\delta}}$ oxide lattice could be determined to be Ni(II).

• Bulletin of the Korean Chemical Society
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• v.22 no.3
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• pp.267-270
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• 2001

The adsorption of chlorine on a Pt(111) surface at 90 K has been studied using scanning tunneling microscopy (STM) in ultra-high vacuum environments. The adsorbed chlorine atoms give rise to two different ordered structures, (3${\times}$3)-Cl and c(4${\times}$2)- Cl, depending on the coverage. It has been determined from the STM image that the absolute coverage of (3${\times}$3)-Cl structure is 0.44, which is not in agreement with coverage calibrated by a low energy electron diffraction technique together with an Auger electron spectrometer and a thermal desorption spectrometer. The Cl atoms bound to on-top sites at the Pt(111)(3${\times}$3)-Cl surface appeared to effectively perturb the density of states of Pt atoms, as compared with that bound to bridging sites. The other ordered structure, c(4${\times}$2)-Cl, with small domain sizes, consists of both on-top and bridge-bonded species with a saturation coverage of 0.5.

• Korean Journal of Materials Research
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• v.32 no.3
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• pp.153-160
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• 2022

ZnO nanosheets have been used for many devices and antibacterial materials with wide bandgap and high crystallinity. Among the many methods for synthesizing ZnO nanostructures, we report the synthesis of ZnO/Zn(OH)₂ nanosheets using the ionic layer epitaxy method, which is a newly-developed bottom-up technique that allows the shape and thickness of ZnO/Zn(OH)₂ nanosheets to be controlled by temperature and time of synthesis. Results were analyzed by scanning electron microscopy and atomic force microscopy. The physical and chemical information and structural characteristics of ZnO/Zn(OH)2 nanosheets were compared by X-ray photoelectron spectroscopy and X-ray diffraction patterns after various post-treatment processes. The crystallinity of the ZnO/Zn(OH)₂ nanosheets was confirmed using scanning transmission electron microscopy. This study presents details of the control of the size and thickness of synthesized ZnO/Zn(OH)₂ nanosheets with atomic layers.

• Journal of the Korean institute of surface engineering
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• v.35 no.3
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• pp.165-171
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• 2002

TiN coating were deposited onto different WC-Co substrates using arc ion plating (AIP) technique. The structure and morphology for the deposited coating were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). The adhesion behavior of the deposited TiN coating was investigated with a conventional scratch test. Effects of WC particle size and Co content on the adhesion strength between the deposited TiN coating and substrate were studied. During the scratch test, the value of critical load was dependent of WC particle size and Co content on substrate. As the WC particle size and Co content on substrate decreased, the critical load increased. The highest critical load, approximately 110N, was obtained at WC particle size of 1$\mu\textrm{m}$ and Co content of 10wt.%.

• Journal of the Korean institute of surface engineering
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• v.35 no.6
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• pp.408-414
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• 2002

TiN and TiAlN coating layer were deposited on WC-Co steel substrates by an arc ion plating(AIP) technique. The crystallinity and morphology for the deposited coating layers were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The impact behaviors of the deposited TiN and TiAlN coating layer were investigated with a ball-on-plate impact tester. Beyond $10^2$ impact cycle, TiAlN coating layer showed superior impact wear resistance compared to TiN coating layer. On the other hand, both TiN and TiAlN coating layers started to be partially failed between $10^2$ and $10^3$ impact cycle. Above $10^3$ impact cycle, TiN and TiAlN coating layers showed similar impact behavior because of the substrate effect.

• Corrosion Science and Technology
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• v.3 no.4
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• pp.148-153
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• 2004

Magnesium thin flims were prepared on cold-rolled steel substrates by RF magnetron sputtering technique. The influence of argon gas pressure and substrate bias voltage on their crystal orientation and morphology of the coated films were investigated by scanning electron microscopy (SEM) and X-ray diffraction, respectively. And the effect of crystal orientation and morphology of magnesium films on corrosion behaviors was estimated by measuring anodic polarization curves in deaerated 3%NaCl solution. From the experimental results, all the sputtered magnesium films showed obviously good corrosion resistance to compare with 99.99% magnesium target of the sputter-evaporation metal. Finally it was shown that the Corrosion-resistance of magnesium films can be improved greatly by controlling the crystal orientation and morphology with effective use of the plasma sputtering technique.