• Journal of Welding and Joining
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• v.10 no.4
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• pp.213-221
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• 1992

Al$_{2}$O$_{3}$ ceramic coating layer by gas flame spraying was very porous, therefore it could not have wear and corrosion resistance at all. To get a dense and strong coating layer, a method to infiltrate an alloy into the pores of $Al_{2}$O$_{3}$ ceramic coating was investigated. Cu-Ti alloys, which had good wettability and reactivity with $Al_{2}$O$_{3}$ ceramic, were examined for infiltration. Infiltration of the alloys was performed in vacuum at 1100.deg.C. The melt of Cu-50 at % Ti alloy was well penetrated through the porous $Al_{2}$O$_{3}$ coating and tightly sealed the pores, unbounded area and microcracks in the coating. The alloy melt in the pores reacted with $Al_{2}$O$_{3}$ ceramic to produce a suboxide phase, Cu$_{2}$Ti$_{4}$O. This composite layer which was composed of $Al_{2}$O$_{3}$ and Cu$_{2}$Ti$_{4}$O phase had good microstructure and wear and corrosion resistance. Additionally, microstructures at interfaces between coating layers were greatly improved owing to the effect of vacuum heat treating.

• Journal of the Korean institute of surface engineering
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• v.36 no.2
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• pp.128-134
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• 2003

Alloys of Ti-43%Al-2%W-0.1%Si were oxidized isothermally and cyclically between $900^{\circ}C$ and$ 1050^{\circ}C$, and their oxidation characteristics were studied. During isothermal tests, the alloys oxidized slowly up to 100$0^{\circ}C$, but fast at $1050^{\circ}C$. Though the scale adherence was not good above $900^{\circ}C$, the alloys displayed better oxidation behavior than unalloyed TiAl alloys. The oxide scales consisted primarily of an outer $TiO_2$ layer, intermediate $Al_2$$O_3$-rich layer, and an inner mixed layer of (TiO$_2$ $+Al_2$$O_3$). Tungsten was present mainly at the lower part of the oxide scale, while Si over the whole oxide scale.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.80-88
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• 2000

The plasma spray technics has known as one of the surface modification methods to improve the mechenical properties or the functional charactristics of materials. This paper has been aimed to investigate the effects of plasma sprayed conditions, such as spray distance and arc power level, on sliding wear properties of plasma sprayed $Al_2$O$_3$-40%TiO$_2$coating layer. The sliding wear test using pin-on-disc type wear machine, has been conducted in several sliding speed for coating layer sparyed under different conditions. The result of this paper is that the wear resistance of plasma sprayed $Al_2$O$_3$-40%TiO$_2$coating layer is fluctuated with tile spray distance and the arc power level. The wear resiatance could be improved with decreasing the spray distance and with increasing the arc power level.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.57-57
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• 2018

Zinc-oxide (ZnO), II-VI semiconductor with a wide and direct band gap (Eg: 3.2~3.4 eV), is one of the most potential candidates to substitute for ITO due to its excellent chemical, thermal stability, specific electrical and optoelectronic property. However, the electrical resistivity of un-doped ZnO is not low enough for the practical applications. Therefore, a number of doped ZnO films have been extensively studied for improving the electrical conductivities. In this study, Ti-doped ZnO films were successfully prepared by atomic layer deposition (ALD) techniques. ALD technique was adopted to careful control of Ti doping concentration in ZnO films and to show its feasible application for 3D nanostructured TCO layers. Here, the structural, optical and electrical properties of the Ti-doped ZnO depending on the Ti doping concentration were systematically presented. Also, we presented 3D nanostructured Ti-doped ZnO layer by combining ALD and nanotemplate processes.

• Korean Journal of Crystallography
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• v.6 no.2
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• pp.111-117
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• 1995

TiO2 thin films were prepared on a (100)silicon wafer using a chemical vapor deposition(CVD) method. The deposition experiments were performed using the TTIP in the deposition temperature ransing from 200 content. The deposition rate of TiO2 was increased with the substrate temperature and the oxygen content. The thickness of the deposited thin film and the compositional analysis of this thin films with theoxygen content were measured using Ellipsometry, SEM and ESCA, respectively. The deposited thin film was composed of a bilayer, external TiO2 and internal Ti. Carbon as a residual impurity was found to remain when zero sccm O2 was purged into a reaction chamber and the composition of the deposited thin film was found to change Ti into TiO in a deeper layer. However, when 600sccm O2 was supplied to a reaction chamber, it has been found to reside less carbon content than without O2. Finally, in the condition of 1200sccm O2, no impurity level of carbon was observed and a deeper layer consisted of the Ti composite, even though the deposited surface was composed of TiO2.

• Journal of Powder Materials
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• v.19 no.3
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• pp.196-203
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• 2012

$TiO_2$ was successfully formed on a Ti specimen by MAO (Micro-Arc-Oxidation) method treated in $Na_3PO_4$ electrolyte. This study deals with the influence of voltage and working time on the change of surface microstructure and phase composition. Voltage affected the forming rate of the oxidized layer and surface microstructure where, a low voltage led to a high surface roughness, more holes and a thin oxidized layer. On the other hand, a high voltage led to more dense surface structure, wider surface holes, a thick layer and fewer holes. Higher voltage increases photocatalytic activity because of better crystallization of the oxidized layer and good phase composition with anatase and rutile $TiO_2$, which is able to effectively separate excited electrons and holes at the surface.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.4
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• pp.85-90
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• 2017

The $TiCl_4$ as a blocking material is adsorbed in the mesoporous $TiO_2$ electron transfer layer(ETL) of the Perovskite solar cell to prevent the direct contact between the FTO electrode and the photoactive layer(AL), and facilitate the movement of the electrons between $TiO_2:TiCl_4$ ETL and Perovskite AL to improve the photoelectric conversion efficiency(PCE). The structure of the perovskite solar cell is FTO/$TiO_2:TiCl_4$/Perovskite($CH_3NH_3PbI_3$)/spiro-OMeTAD/Ag. It was investigated that the dipping time of the $TiO_2$ into $TiCl_4$ aqueous solution affects on the photoelectric characteristics of the device. By the dipping for 30 minutes, the PCE of the perovskite solar cell with the $TiO_2:TiCl_4$ ETL was the highest 10.46%, which is 27% higher than the cell with $TiO_2$ ETL. From SEM, EDS, and XRD characterization on the $TiO_2:TiCl_4$ ETL and the perovskite AL, it was measured that the decrease of the porosity of the $TiO_2$ layer, the detection of the Cl component by the $TiCl_4$ adsorption, the cube-type morphology of perovskite AL, and shift of the $PbI_2$ peak of the perovskite AL. From these results, it was confirmed that the $TiO_2:TiCl_4$ ETL and the perovskite AL were formed.

• KIEE International Transactions on Electrophysics and Applications
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• v.12C no.4
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• pp.208-213
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• 2002

The present study describe the electrical performance of amorphous T $a_2$ $O_{5-X}$ fabricated on the buffer layers Ti and Ti $O_2$. T $a_2$ $O_{5-X}$ thin films were grown on the Ti and Ti $O_2$ layers as a capacitor layer using reactive sputtering method. The X-ray pattern analysis indicated that the two as-deposited films were amorphous and the amorphous state was kept stable on the RTA(rapid thermal annealing) at even $700^{\circ}C$. Measurements of dielectric properties of the reactive sputtered T $a_2$ $O_{5-X}$ thin films fabricated in two simple MIS(metal insulator semiconductor), structures, (Cu/T $a_2$ $O_{5}$ Ti/Si and CuT $a_2$ $O_{5}$ Ti $O_2$Si) show that the amorphous T $a_2$ $O_{5}$ grown on Ti showed high dielectric constant (23～39) and high leakage current density(10$^{-3}$ ～10$^{-4}$ (A/$\textrm{cm}^2$)), whereas relatively low dielectric constant (～15) and tow leakage current density(10$^{-9}$ ～10$^{-10}$ (A/$\textrm{cm}^2$)) were observed in the amorphous T $a_2$ $O_{5}$ deposited on the Ti $O_2$ layer. The electrical behaviors of the T $a_2$ $O^{5}$ thin films were attributed to the contribution of Ti- $O_2$ and the compositionally gradient Ta-Ti-0, being the low dielectric layer and high leakage current barrier. In additional, The T $a_2$ $O_{5}$ Ti $O_2$ thin films exhibited dominant conduction mechanism contributed by the Poole-Frenkel emission at high electric field. In the case of T $a_2$ $O_{5}$ Ti $O_2$ thin films were related to the diffusion of Ta, Ti and O, followed by the creation of vacancies, in the rapid thermal treated thin films.films.

• JSTS:Journal of Semiconductor Technology and Science
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• v.8 no.1
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• pp.80-84
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• 2008

We systematically investigated the resistive switching properties of thin $TiO_2$ films on Pt/Ti/$SiO_2$/Si substrates that were embedded with a Co ultra thin layer. An in-situ sputtering technique was used to grow both films without breaking the chamber vacuum. A stable bipolar switching in the current-voltage curve was clearly observed in $TiO_2$ films with an embedded Co ultra thin layer, addressing the high and low resistive state under a bias voltage sweep. We propose that the underlying origin involved in the bipolar switching may be attributed to the interface redox reaction between the Co and $TiO_2$ layers. The improved reproducible switching properties of our novel structures under forward and reverse bias stresses demonstrated the possibility of future non-volatile memory elements in a simple capacitive-like structure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.12
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• pp.809-813
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• 2016

We investigated a SiC-based hydrogen gas sensor with MIS (metal-insulator-semiconductor) structure for high temperature applications. The sensor was fabricated by $Pd/TiO_2/SiC$ structure, and a thin titanium dioxide ($TiO_2$) layer was exploited for sensitivity improvement. In the experiment, dependences of I-V characteristics and capacitance response properties on hydrogen gas concentrations from 0 to 2,000 ppm were analyzed at room temperature to $400^{\circ}C$. As the result, our sensor using $TiO_2$ dielectric layer showed possibilities with regard to use in hydrogen gas sensors for high-temperature applications.