• Journal of the Korean Vacuum Society
• /
• v.6 no.4
• /
• pp.314-320
• /
• 1997

A chemical reaction and electronic structure change at the interface between copper and titanium nitride were investigated by XPS. A thin Cu layer was deposited on a TiN substrate oxidized by exposure to air at room temperature. We observed the Ti(2p), O(1s), N(1s), Cu(2p) core-level, and Cu LMM Auger line spectra. With increasing of the thickness of Cu layer, these spectra do not show any changes in the line shape as well as in peak position. In addition, the valence band spectra in XPS do not show any changes, which indicates that Cu does not react with Ti, N, and O. This inreactivity of Cu might cause a poor adhesion between Cu and TiN.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.11b
• /
• pp.480-483
• /
• 2001

Epitaxial rutile-$TiO_2$ and anatase-$TiO_2$ films were grown at $800^{\circ}C$ on $Al_2O_3$ (1102) and $LaAlO_3$ (001), respectively, using pulsed laser deposition. The formation of different phases on different substrates could be qualitatively explained by the atomic arrangements at the interfaces. We also successfully deposited epitaxial rutile-$TiO_2$ and anatase-$TiO_2$ films on conductive $RuO_2$ and $La_{0.5}Sr_{0.5}CoO_{3}$ electrodes, respectively. Using a Kelvin probe, we measured the photovoltaic properties of these multilayer structures. A rutile-$TiO_2$ film grown on $RuO_2$ showed a very broad peak in the visible light region. An epitaxial anatase-$TiO_2$ film grown on $La_{0.5}Sr_{0.5}CoO_{3}$ showed a strong peak with a threshold energy of 3.05 eV.

• Journal of Powder Materials
• /
• v.24 no.1
• /
• pp.29-33
• /
• 2017

Titanium carbide (TiC) powders are successfully synthesized by carburization of titanium hydride ($TiH_2$) powders. The $TiH_2$ powders with size lower than $45{\mu}m$ (-325 Mesh) are optimally produced by the hydrogenation process, and are mixed with graphite powder by ball milling. The mixtures are then heat-treated in an Ar atmosphere at $800-1200^{\circ}C$ for carburization to occur. It has been experimentally and thermodynamically determined that the de-hydrogenation, "$TiH_2=Ti+H_2$", and carburization, "Ti + C = TiC", occur simultaneously over the reaction temperature range. The unreacted graphite content (free carbon) in each product is precisely measured by acid dissolution and by the filtering method, and it is possible to conclude that the maximal carbon stoichiometry of $TiC_{0.94}$ is accomplished at $1200^{\circ}C$.

• Environmental Analysis Health and Toxicology
• /
• v.19 no.3
• /
• pp.271-278
• /
• 2004

Epoxy resins are mostly used as a molding material for drinking water tank. Bisphenol A is used at a constituent material for epoxy resins and is widely suspected to act as an endocrine disrupter. In this study, we investigated embryo hatching in zebrafish reared in water undergone leaching process of expoxy resin, and found a decreased survival rate. Bisphenol A eluted from epoxy resin in drinking water tank was completely degraded by TiO$_2$ photocatalysis. We detected 7.8 ng/ml of bisphenol A in epoxy resin tank, and observed that the concentration was undetectable after 48h photocatalysis over TiO$_2$. There was no toxicity in hatching rates in zebrafish and morphogenesis after photocatalysis. The effect of TiO$_2$ photocatalytic reactions on the catalase activities in the f]y stage of zebrafish was also examined. At 1 week post hatching, cataiase activities were higher both in the group of epoxy resin with 48 h TiO$_2$ photocatalysis and in the TiO$_2$ photocatalysis for 48 hours were higher than control group. However catalase activities of the treatment group of epoxy resin by TiO$_2$ photocatalysis for 48 hours were similar to control in 5 weeks post hatching fries. In conclusion, the toxicity of TiO$_2$ photocatalysis was not observed in this zebrafish.

• Journal of Powder Materials
• /
• v.19 no.4
• /
• pp.310-316
• /
• 2012

Nanocrystalline $BaTiO_3$ powder could be synthesized by solid-state reaction using the mixture which was prepared by a high energy milling process in a bead mill for $BaCO_3$ and nanocrystalline $TiO_2$ powders mixture. Effect of the milling time on the powder characteristic of the synthesized $BaTiO_3$ powder was investigated. Nanocrystalline $BaTiO_3$ with a particle size of 50 nm was obtained at $800^{\circ}C$. High tetragonal $BaTiO_3$ powder with a tetragonality(=c/a) of 1.009 and a specific surface area of $7.6m^2/g$ was acquired after heat-treatment at $950^{\circ}C$ for 2 h. High energy ball milling was effective in decreasing the reaction temperature and increasing the tetragonality.

• Journal of the Korean Ceramic Society
• /
• v.36 no.7
• /
• pp.691-697
• /
• 1999

TiO2 powder was adsorbed on the surface of mica using the heterocoagulation method in water TiO2 powder was prepared from hydrolysis of titanium-iso propoxide in a mixed solvent of anhydrous ethanol and water. When the molar ratio of water to titanium iso-propoxide was 0.25 monodispersed spherical TiO2 particles were obtained. The prepared TiO2 powder showed anatase phase after heat treatment at 50$0^{\circ}C$ for 2 h and then transformed to rutile phase after heat treatment at 100$0^{\circ}C$ for 2h. The iso-electric points of TiO2 and Mica were pH 3.9 and pH 3.25 respectively which were measured by the Z-potential analysis in water base. The maximum Z-potential difference between two powders was observed in the range of pH 3.6~3.7 TiO2 powder was adsorbed on the surface of mica by heterocoagulation method in pH 3.6~3,7 The properties of prepared TiO2 powder was haracterized by TG-DTA, XRD and SEM The morphology and thermal properties of TiO2-adsorbed mica were examined.

• Journal of the Korean Ceramic Society
• /
• v.49 no.6
• /
• pp.642-647
• /
• 2012

$TiO_2$ thin films for a pulse power capacitor were deposited by RF magnetron sputtering. The effects of the deposition gas ratio and thickness on the crystallization and electrical properties of the $TiO_2$ films were investigated. The crystal structure of $TiO_2$ films deposited on Si substrates at room temperature changed to the anatase from the rutile phase with an increase in the oxygen partial pressure. Also, the crystallinity of the $TiO_2$ films was enhanced with an increase in the thickness of the films. However, $TiO_2$ films deposited on a PET substrate showed an amorphous structure, unlike those deposited on a Si substrate. An X-ray photoelectron spectroscopy(XPS) analysis revealed the formation of chemically stable $TiO_2$ films. The dielectric constant of the $TiO_2$ films as a function of the frequency was significantly changed with the thickness of the films. The films showed a dielectric constant of 100~110 at 1 kHz. However, the dissipation factors of the films were relatively high. Films with a thickness of about 1000nm showed a breakdown strength that exceeded 1000 kV/cm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.11a
• /
• pp.480-483
• /
• 2001

Epitaxial rutile-TiO$_2$ and anatase-TiO$_2$ films were grown at 80$0^{\circ}C$ on $Al_2$O$_3$ (1102) and LaAlO$_3$ (001), respectively, using pulsed laser deposition. The formation of different phases on different substrates could be qualitatively explained by the atomic arrangements at the interfaces. We also successfully deposited epitaxial rutile-TiO$_2$ and anatase-TiO$_2$ films on conductive RuO$_2$ and La$_{0.5}$Sr$_{0.5}$CoO$_3$ electrodes, respectively Using a Kelvin probe, we measured the photovoltaic properties of these multilayer structures. A rutile-TiO$_2$ film grown on RuO$_2$ showed a very broad peak in the visible light region. An epitaxial anatase-TiO$_2$ film grown on La$_{0.5}$Sr$_{0.5}$CoO$_3$ showed a strong peak with a threshold energy of 3.05 eV 3.05 eV

• Journal of the Korean institute of surface engineering
• /
• v.34 no.4
• /
• pp.321-326
• /
• 2001

The TiCrN Coatings haying three kinds of Compositions of $Ti_{36}$ $Cr_{26}$ $N_{38}$ , $Ti_{31}$ $Cr_{35}$ $N_{34}$ / and $Ti_{14}$ $Cr_{52}$ $N_{34}$ were deposited on STD 61 steel substrate by arc ion plating and were oxidized between 700 and 100$0^{\circ}C$ to identify the oxide scales formed on the coatings. The oxide scales were then analyzed using EPMA, XRD and GAXRD. During oxidation, the coatings consisting of TiN and CrN phases were reduced to TiO2 and $Cr_2$$O_3$, respectively. Titania tended to form at the outer oxide layer, whereas chromia tended to form at the inner oxide layer, owing to the different oxygen affinity. The substrate elements as well as coating elements diffused outwardly toward the oxide layer due to the concentration gradient. The growth of oxide from the TiCrN coatings was schematically expressed on the basis of thickness measurement of the reacted and unreacted coatings. The Cr element showed its stronger role to keep the TiCrN coatings from oxidation, when compared with Ni.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.11a
• /
• pp.282-285
• /
• 1999

The (1-x)MgTiO$_3$-xSrTiO$_3$(x=0,0.1) ceramics were prepared by the conventional mixed oxide method. The structural properties were investigated with sintering temperature and composition ratio by XRD, SEM and DT-TGA. Increasing the sintering temperature from 130$0^{\circ}C$ to 1$600^{\circ}C$, second phase was decreased and grain size was increased. In the case of 0.9 MgTiO$_3$-0.1SrTiO$_3$ ceramics sintered at 130$0^{\circ}C$, dielectric constant, quality factor and temperature coefficient of resonant frequency were 22.61, 10,928(at 1GHz), +50.26ppm/$^{\circ}C$ , respectively.