• International Journal of Advanced Culture Technology
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• v.3 no.2
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• pp.25-33
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• 2015

This study aims to synthesis the self-cleaning fibers. The nano-titanium dioxide ($TiO_2$) were blend with the polypropylene (grade 561R) at 1wt%, 3wt%, 5wt%, 10wt%, 15wt% and 20wt%. The $TiO_2$-fibers were obtained from single screw extruder. The mechanical, thermal, rheology and self-cleaning properties were also investigated. The results showed that the tensile strength of the $nTiO_2$-PP fibers decreased with increasing of the amount of $TiO_2$. The presents of the $TiO_2$ in the PP fibers significantly showed the improving of the self-cleaning properties under sunlight and 20 watt of UV radiation. The $TiO_2$-PP fibers in presents of $TiO_2$ 20wt% showed the best results of self-cleaning under 5 hours of the sunlight which the similar results were found under 5 hours of 20 watts of UV radiation.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.10a
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• pp.213-214
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• 2009

A thin film hydroxyapatite (HA) films was deposited on anodized titanium by RF sputtering method. The anodized titanium enhanced the biocompatibility of the Ti and the bioactivity was improved further by the HA deposited on the anodized Ti. $TiO_2$ layer with $0.2{\sim}0.5{\mu}$ diameter pore size was formed on the Ti surface by anodization. Anodized $TiO_2$ layer analysis HA film deposited, oxide pore size and number decreased compared with non-HA deposited surface. The corrosion resistance of HA deposited/anodized Ti was higher than that of the non-treatment Ti alloy in Hank's solution, indicating better protective effect. From the results of cell culture using MTT assays, the best cell proliferation showed in HA deposited surface after anodization of Ti surfaces compared with another surface treatment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.8-13
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• 2012

Ti-3Al-2.5V ingot was produced, processed into a titanium alloy wire of 9mm diameter, and the characteristics were studied in comparison with imported material. The ingot satisfied ASTM Grade 9 standard showing oxygen content of 0.11wt% and iron content of 0.085wt%. The hardness of the 9mm diameter titanium alloy was similar to that of the imported material showing values between 225 and 250Hv, and the tensile strength of the imported material was 804MPa while that of the domestic development was 734MPa. The elongation of the imported material was 12% while that of the domestic development was 22%. A new process of manufacturing 9.0mm diameter titanium alloy wire through forging and multi-step hot rolling process out of 400mm diameter ingot was developed.

• Corrosion Science and Technology
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• v.21 no.5
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• pp.340-347
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• 2022

In this research, mixed metal oxide (TiO₂, RuO₂) coating was applied to grade 1 titanium as a bipolar plate for polymer electrolyte membrane fuel cell (PEMFC). Electrochemical experiments were carried out in an aqueous solution of pH 3 (H₂SO₄ + 0.1 ppm HF, 80 ℃) determined by DoE. The air was bubbled to simulate a cathode environment. Potentiodynamic polarization test revealed that corrosion current densities of the titanium substrate and MMO-coated specimen were 0.180 µA/cm² and 4.381 µA/cm², respectively. There was no active peak. After potentiostatic experiment, current densities of the titanium substrate and the MMO-coated specimen were 0.19 µA/cm² and 1.05 µA/cm², respectively. As a result of observing the surface before and after the potentiostatic experiment, cracked dried clay structures were observed without corrosion damage. Both the titanium substrate and the MMO-coated specimen could not satisfy the interfacial contact resistance suggested by the DoE. Thus, further research is needed before they could be applied as bipolar plates.

• Korean Journal of Materials Research
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• v.12 no.11
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• pp.883-888
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• 2002

We investigated the void formation in composite-titanium silicide($TiSi_2$) process. We varied the process conditions of polycrystalline/amorphous silicon substrate, composite $TiSi_2$ deposition temperature, and silicidation annealing temperature. We report that the main reason for void formation is the mass transport flux discrepancy of amorphous silicon substrate and titanium in composite layer. Sheet resistance in composite $TiSi_2$ without patterns is mainly affected by silicidation rapid thermal annealing (RTA) temperature. In addition, sheet resistance does not depend on the void defect density. Sheet resistance with sub-0.5 $\mu\textrm{m}$ patterns increase abnormally above $850^{\circ}C$ due to agglomeration. Our results imply that $sub-750^{\circ}C$ annealing is appropriate for sub 0.5 $\mu\textrm{m}$ composite X$sub-750_2$ process.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.80-81
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• 2009

Ti-6Al-4V alloy has been widely used for aerospace and power generation applications because of low density and attractive mechanical and corrosion resistant properties. However, the titanium alloy bolt is generally manufactured by cutting and rolling because of their poor workability. In order to achieve the mass production of titanium alloy bolts, it needs to be solved some manufacturing problems such as the sticking between workpiece and dies, the formation of the forming defects during the forging and so on. In this study, the manufacturing technology of titanium alloy bolts using warm forging process was introduced. The aim of present work is to develop a warm forging technology for high strength Ti-6Al-4V bolts.

• Macromolecular Research
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• v.15 no.1
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• pp.31-38
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• 2007

Pentamethylcyclopentadienyltitanium trichloride, bis(cyclopentadienyl)titanium dichloride ($Cp_2TiCl_2$), and bis(pentamethylcyclopentadienyl)titanium dichloride were used in the polymerization of styrene without the aid of Group I-III cocatalysts. The properties of the resulting polymer indicated that polymerization was more controlled than in thermal polymerization. The kinetic studies indicated that a lower level of termination is present and that the polymer chain can be extended by adding an additional monomer. To elucidate the mechanism of polymerization, a series of experiments was performed. All results supported the involvement of a radical mechanism in the polymerization using $Cp_2TiCl_2$. The possibility of atom transfer radical polymerization (ATRP) mechanism was investigated by isolating the intermediate species. We could confirm the activation step from the reaction of 1-PEC1 with $Cp_2TiCl$ by detecting the coupling product of the generated active radicals. However, the reversible deactivation reaction competes with other side reactions, and it detection was difficult with our model system.

• Korean Journal of Materials Research
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• v.15 no.3
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• pp.209-215
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• 2005

Titanium dioxide films $(TiO_2)$ doped cobalt transition metal were prepared on titanium metal by water spray pyrolysis technique. Micro-morphology, crystalline structure, chemical composition and binding state of sample groups were evaluated using field emission scanning microscope(FE-SEM), X-ray diffractometer(XRD), Raman spectrometer, X-ray photoelectron spectrometer(XPS). $TiO_2$ films of rutile structure were predominately formed on all sample groups and $Ti_2O_3$ oxide was coexisted on the surface of cobalt doped-sample groups. The optical absorption peaks measured by using UV-VIS-NIR spectrophotometer were observed at specific wavelength region in sample groups doped cobalt ion. This result could be analyzed by introducing crystal field theory.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.3
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• pp.252-258
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• 2013

In this paper, a thermally stable nickel silicide technology using the co-sputtering of nickel and titanium atoms capped with TiN layer is proposed for nano-scale metal oxide semiconductor field effect transistor (MOSFET) applications. The effects of the incorporation of titanium ingredient in the co-sputtered Ni layer are characterized as a function of Ti sputtering power. The difference between the one-step rapid thermal process (RTP) and two-step RTP for the silicidation process has also been studied. It is shown that a certain proportion of titanium incorporation with two-step RTP has the best thermal stability for this structure.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2003.10a
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• pp.59-59
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• 2003

In recent, various functional coatings on artificial tooth implants have been conducted to enhance the bonding strength between implants and bones. Despite of these efforts, some previous reports argued that an adhesion strength between titanium implant and the final coatings like hydroxyapatite(HA) is weaker than the strength between coating and bone. In order to increase the adhesion force between the final coating and implant surface, TiN/DLC based functionally graded coating, which has higher mechanical strength than the titanium implant, was applied as a middle layer between titanium implant and final coating. Particularly we finally coated a biocompatible hydroxyapatite film on the DLC layer and examined the mechanical properties. As a result, TiN/DLC based functionally graded coating showed the higher adhesion strength compared with hydroxyapatite single layer coating on the titanium implant.