• Applied Chemistry for Engineering
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• v.10 no.4
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• pp.603-607
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• 1999

The polarization characteristics of poly(vinyl alcohol)-iodine complex, (PVA-KI system) prepared by the oxidation process of PVA film containing a potassium iodide (KI) were investigated. The UV-visible spectrum of the PVA-KI system polarizing film showed avsorption bands corresponding to $I^{-}$, $I{_3}{^-}$ and $I{_5}{^-}$ chromophoric species at 220 nm, 290~360 nm, respectively. The polarization efficiency and transmittance of PVA-KI system film were significantly influenced by oxidation time, stretching ratio and concentration of KI. The prepared polarizing film exhibited a high polarization efficiency(99.5%) and transmittance(45%). Especially, the heat resistance of the polarizing film was higher than that of a commercial PVA-$I_2$ polarizing film. It may be argued that the result should come from a difference in oxidation process of PVA polarizing film.

• Korean Journal of Materials Research
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• v.11 no.4
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• pp.324-328
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• 2001

CrN films were deposited onto STD61 steel substrates using an arc-ion plating apparatus, with and without ion-nitriding pretreatment, and their oxidation was studied between 700 and $900^{\circ}C$ for 40hr in air. The oxidation behavior was examined by thermogravimetric analyses, X-ray diffraction. EDS and SEM. The deposited CrN films consisted of CrN and $Cr_2$N phases. The CrN films increased the oxidation resistance of the substrate by forming a protective $Cr_2$$O_3$ layer. The ion-nitriding pretreatment has not affected the oxidation resistance of the CrN film.

• Journal of the Korean Chemical Society
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• v.10 no.4
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• pp.153-157
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• 1966

The measurement of Oxidation of nickel has been investigated using vacuum quartz microbalance in the temperature range of $500^{\circ}{\sim}800^{\circ}C$ at various oxygen pressure. The rate constants of nickel-oxidation were evaluated according to the parabolic rate law. From the Arrhenius equation, the activation energy in the range of experimental temperatures were found that $E_{act}$= 35.4 Kcal/mole. It was also found that the parabolic rate constants varied approximately as the one fifth power of the oxygen pressure for nickel-oxidation. The mechanism for the oxidation of this metal were seemed to be via cation vacancy produced by excess of oxygen dissolved in the oxide film.

• The Korean Journal of Food And Nutrition
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• v.18 no.1
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• pp.19-27
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• 2005

Antioxidative polyethylene films for food packaging were experimentally prepared by fortification of TBHQ(tertiary butylhydroquinone) and dl-a-tocopherol at the weight ratio of 0.05, 0.2 and 0.5%, respectively and laminated with nylon. TBHQ and tocopherol contents in the PE/nylon film were analyzed and the antioxidative effects of film were investigated on the lipid oxidation of semi-dried squid during storage at 5℃ and l5℃. TBHQ contents of TAP 1(TBHQ 0.05%), TAP 2(TBHQ 0.2%) and TAP 3(0.5%) were 38, 146 and 365 mg/100g, respectively. Tocopherol contents of DAP l(tocopherol 0.05%), DAP 2(tocopherol 0.2%) and DAP 3(tocopherol 0.5%) were 33, 139 and 356 mg/l00g, respectively. TBA value and POV during storage of semi-drid squid were affected both by storage temperatures and packaging films. Lipid oxidation during storage was retarded by anti-oxidative films, as TBA value of TAP 3 and DAP 3 revealed about 50% of control after storage at 5℃ for 20 days and similer effects in POV were also observed.

• Journal of the Korean institute of surface engineering
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• v.52 no.5
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• pp.258-264
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• 2019

Assembling heterostructures by combining dissimilar oxide semiconductors is a promising approach to enhance charge separation and transfer in photoelectrochemical (PEC) water splitting. In this work, the CuO nanorods array/$Cu_2O$ thin film bilayered heterostructure was successfully fabricated by a facile method that involved a direct electrodeposition of the $Cu_2O$ thin film onto the vertically oriented CuO nanorods array to serve as the photoelectrode for the PEC water oxidation. The resulting copper-oxide-based heterostructure photoelectrode exhibited an enhanced PEC performance compared to common copper-oxide-based photoelectrodes, indicating good charge separation and transfer efficiency due to the band structure realignment at the interface. The photocurrent density and the optimal photocurrent conversion efficiency obtained on the CuO nanorods/$Cu_2O$ thin film heterostructure were $0.59mA/cm^2$ and 1.10% at 1.06 V vs. RHE, respectively. These results provide a promising route to fabricating earth-abundant copper-oxide-based photoelectrode for visible-light-driven hydrogen generation using a facile, low-cost, and scalable approach of combining electrodeposition and hydrothermal synthesis.

• Journal of the Korean institute of surface engineering
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• v.51 no.6
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• pp.381-386
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• 2018

In this study, plasma electrolytic oxidation (PEO) method was used to from anodic oxide films on Al alloy and their resistance and morphological characteristics were investigated as a function of film formation voltage and treatment time. Cross-sectional morphology and composition of the PEO films were analyzed by SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive Spectroscopy). The PEO films showed increased surface roughness and thickness with of film formation voltage and treatment time. The wear resistance was found to be the best for the PEO film formed for 5 min at 500V which is attributed to be denser structure relatively and lower surface roughness.

• Journal of the Korean institute of surface engineering
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• v.53 no.5
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• pp.201-206
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• 2020

A SiOxCy(-H) thin film was synthesized by atmospheric pressure dielectric barrier discharge(APDBD), and a SiO₂-like layer was formed on the surface of the film by oxidation treatment using oxygen plasma. Hexamethylcyclotrisiloxane was used as a precursor for the SiOxCy(-H) synthesis, and He gas was used for stabilizing APDBD. Oxygen permeability was evaluated by forming an oxidized SiOxCy(-H) thin film on a PET film. When the single-layer oxidized SiOxCy(-H) film was coated on the PET, the oxygen gas permeability decreased by 46% compared with bare PET. In case of three-layer oxidized SiOxCy(-H) film, the oxygen gas permeability decreased by 73%. The oxygen permeability was affected by the thickness of the SiO₂-like layer formed by oxidation treatment rather than the thickness of the SiOxCy(-H) film. The excellent corrosion resistance was demonstrated by coating an oxidized SiOxCy(-H) thin film on the silver-coated aluminum PCB for light emitting diode (LED).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.1
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• pp.33-40
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• 1998

The composite SiO$_2$/Si$_3$N$_4$/SiO$_2$(ONO) film formed by oxidation on nitride film has been widely studied as DRAM stacked capacitor multi-dielectric films. Load lock(L/L) LPCVD system by HF cleaning is used to improve electrical capacitance and to scale down of effective thickness for memory device, but is brings a new problem. Nitride film deposited using HF cleaning shows selective deposition on poly silicon and oxide regions of capacitor. This problem is avoidable by carpeting chemical oxide using $H_2O$$_2$cleaning before nitride deposition. In this paper, we study the limit of nitride thickness for abnormal oxidation and the initial deposition time for nitride deposition dependent on underlayer materials. We proposed an advanced fabrication process for stacked capacitor in order to avoid selective deposition problem and show the usefulness of nitride deposition using L/L LPCVD system by $H_2O$$_2$cleaning. The natural oxide thickness on polysilicon monitor after HF and $H_2O$$_2$cleaning are measured 3~4$\AA$, respectively. Two substrate materials have the different initial nitride deposition times. The initial deposition time for polysilicon is nearly zero, but initial deposition time for oxide is about 60seconds. However the deposition rate is constant after initial deposition time. The limit of nitride thickness for abnormal oxidation under the HF and $H_2O$$_2$cleaning method are 60$\AA$, 48$\AA$, respectively. The results obtained in this study are useful for developing ultra thin nitride fabrication of ONO scaling and for avoiding abnormal oxidation in stacked capacitor application.

• Elastomers and Composites
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• v.54 no.2
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• pp.110-117
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• 2019

The characterization of the ozone oxidation for raw natural rubber (NR) was investigated under controlled conditions through image and fourier transform infrared (FT-IR) analysis. The ozone oxidation was performed on a transparent thin film of raw NR coated on a KBr window in a dark chamber at $40^{\circ}C$ under low humidity conditions to completely exclude thermal, moisture, or light oxidation. The ozone concentration was set at 40 parts per hundred million (pphm). Before or after exposure to ozone, the image of the thin film for raw NR was observed at a right or tilted angle. FT-IR absorption spectra were measured in the transmission mode according to ozone exposure time. The ozone oxidation of NR was determined by the changes in the absorption peaks at 1736, 1715, 1697, and $833cm^{-1}$, which were assigned to an aldehyde group (-CHO), a ketone group (-COR), an inter-hydrogen bond between carbonyl group (-C=O) from an aldehyde or a ketone and an amide group (-CONH-) of protein, and a cis-methine group ($is-CCH_3=CH-$, respectively. During ozone exposure period, the results indicated that the formation of the carbonyl group of aldehyde or ketone was directly related to the decrement of the double bond of cis-1,4-polyisoprene. Only carbonyl compounds such as aldehydes or ketones seemed to be formed through chain scission by ozone. Long thin cracks with one orientation at regular intervals, which resulted in consecutive chain scission, were observed by image analysis. Therefore, one possible two-step mechanism for the formation of aldehyde and ketone was suggested.

• Journal of the Korean Ceramic Society
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• v.29 no.11
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• pp.863-869
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• 1992

A SOG(spin glass) solution with excellent wetting to Si wafers was prepared by acid-hydrolysis of Si(OEt)4 and Me2Si(OEt)2. The solution was spin coated on Si wafers, and effects of heat treatment of the film were characterized by TG/DTA, FTIR and Ellipsometry. Silica film was obtained by heat treatment at $600^{\circ}C$ within one hour, but heat treatment at 80$0^{\circ}C$ caused interfacial oxidation of the silicon substrate. Unexpectedly silica films with much better adhesion were obtained by curing at $600^{\circ}C$ for over 30 min. than those obtained by thermal oxidation.