• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.12-13
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• 2006

The spherical and high quality Titanium fine powder "Tilop" has been produced with gas atomization furnace, Sumitomo Titanium Corporation originally designed. Recently, a new process which can produce Ti-alloy(Ti-6Al-4V) powders by utilizing our gas atomization process, of which raw material is sponge titanium pre-mixed with alloy chips or granules has been also developed. The particle size of gas atomized Ti-alloy powder and the mechanical properties of sintered Ti-alloy compacts prepared by metal injection molding were discussed in this study.

• Journal of the Korean Vacuum Society
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• v.6 no.S1
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• pp.1-15
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• 1997

Titanium oxide films were prepared by ion beam enhanced deposition where the films were synthesized by deposition titianium atoms and simultaneously bombarding with xenon ion beam at an energy of 40 keV in an $O_2$ environ,ent. Structure and composition of titanium oxide films were investigated by X-ray Doffractopm (XRD) Ritjerfprd Backscattering Spectroscopy (RBS) and X-ray Diffraction(XRD) Rutherford Backscattering Spectroscopy (RBS) and X-ray photoelectron spectroscopy (XPS) The results show that thestructure of the prepared films exhibit a rutile phase structure wit high(200) orientation and the O/Ti ratio of the titanium oxide films was about 2:1 XPS anlysis shows that $Ti^{2+},Ti^{3+}\;and\;Ti^{4+}$ chemical states exist on the titanium oxide films. the blood compatibility of the titanium oxide films was studied by measurements of blood clotting time and platelet adhesion. The results show that the anticoagulation property of titanium oxide films improved significantly and better than that of LTI-carbon which was widely used to fabricate artificial heart valve.

• Analytical Science and Technology
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• v.12 no.6
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• pp.509-514
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• 1999

The systematic modification of titanium(IV) isopropoxide with acetic acid as a organic additive was done and identifided by FT-IR, $^1H$, $^{13}C$ NMR and UV-Vis spectroscopy. The structure was cbanged after hydrolysis-condensation reaction and drying process. The hydrolysis-condensation rates of modified Ti alkoxide with acetic acid were investigated by $^1H$ NMR spectroscopy. This modified Ti(IV) alkoxide was less reactive toward hydrolysis-condensation reaction than $Ti(OPr^i)_4$, which can be attributed to the stable ligand structure between Ti alkoxide and ligand. The structural change on obtained from gel powders with heat treatment was also observed by FT-IR spectroscopy.

• Journal of the Korean Society of Safety
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• v.16 no.3
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• pp.76-82
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• 2001

An aqueous solution of a commercial liquid synthetic detergent for kitchen use was photodecomposed in the presence of titanium dioxides ponder under an atmosphere of air at room temperature. Titanium dioxides were prepared by sol-gel method from titanium iso-propoxide at different R R ratio($H_2O$/titanium iso-propoxide) and calcined at $500^{\circ}C$. All titanium dioxides m characterized by XRD, BET surface area analyzer and UV-VIS spectrometer. The surface mea of titanium dioxides prepared at R ratio=6 appeared higher volume about 20% than commercial $TiO_2$ catalyses. XRD patterns of titania particles were observed mixing phase together with rutile and anatase type. Titanium dioxides prepared by sol-gel method show higher activity about 6% than commercial $TiO_2$ catalysts on the Photocatalytic foundation of a commercial liquid synthetic detergent for kitchen. The concentration of the detergent decreased to about 90%, of its initial value at illumination times of 2 hour. illumination for 30 minutes decreased the concentration of oxygen to about one-fifth of the initial value.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.4
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• pp.522-533
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• 2007

Statement of problem: Despite of the recent development of the titanium casting system methods, the casting defects such as imperfect casting and internal porosity were frequently observed. Purpose: The purposes of this study were to compare and measure the castability, microhardness, and surface reaction between Grade 2 pure titanium and Ti-6Al-4V by casting these alloys from the different sprue design conditions. Material and methods: Depending on the sprue designs and titanium alloys, 42 ready-made wax patterns were used. By analyzing the remodeling of the cast, internal porosity, microhardness, and titanium surface layer of SEM, there were several results we observed. Results: 1. The measured castability of titanium were categorized in the ascending order: individual sprue group, runner bar group, and single group. This data are based on the statistically signigicant differences. 2. The castability of titanium has not showed the statistically significant differences among the alloys. However, CP-Ti groups were superior to Ti-6Al-4V groups by showing the noticeable castability. 3. The surface layers of the castings of all groups have showed $5{\mu}m$ titanium oxide layers irrespective of sprue designs and titanium alloys. Conclusion: From the above study results, by fabricating the restorations from the centrifugal casting machine direct sprue designs revealed better castability. As we increased the number of sprues in the wax pattern, it revealed better castability. The castability of pure titanium rather than that of Ti-6Al-4V was remarkable. To fabricate the complex forms of the restorations, further researches on the efficient sprue designs and titanium alloys must be made.

• Bulletin of the Korean Chemical Society
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• v.25 no.5
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• pp.681-686
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• 2004

Ti-ZSM-5 prepared by secondary synthesis, from the reaction of H-ZSM-5 with vapor phase $TiCl_4$, was characterized with several physicochemical techniques including FT-IR and UV/VIS-DRS. It was found that zeolite structure, surface area and pore volume did not change, and the framework aluminum could not be replaced by titanium atom during the secondary synthesis of Ti-ZSM-5. The incorporation of titanium into the framework might be due to reaction of $TiCl_4$with the silanol groups associated with defects or surface sites. The formation of extra-framework titanium could not be avoided, unless the samples were further treated by water vapor at 550 $^{\circ}C$ or higher temperature. High temperature steam treatment of Ti-ZSM-5 prepared by chemical vapor deposition with $TiCl_4$was efficient to prevent the formation of non-framework titanium species. Ti-ZSM-5 zeolites prepared in this work contained only framework titanium species and exhibited improved catalytic property close to TS-1 prepared by hydrothermal synthesis.

• Korean Journal of Materials Research
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• v.34 no.5
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• pp.254-260
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• 2024

This study is to manufacture a titanium dioxide (TiO₂) photocatalyst by recycling sludge generated using titanium tetrachloride (TiCl₄) as a coagulant. Compared to general sewage, a TiCl₄ coagulant was applied to dyeing wastewater containing a large amount of non-degradable organic compounds to evaluate its performance. Then the generated sludge was dried and fired to prepare a photocatalyst (TFS). Scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), and nitrogen oxide reduction experiments were conducted to analyze the surface properties and evaluate the photoactive ability of the prepared TFS. After using titanium tetrachloride (TiCl₄) as a coagulant in the dyeing wastewater, the water quality characteristics were measured at 84 mg/L of chemical oxygen demand (COD), 10 mg/L of T-N, and 0.9 mg/L of T-P to satisfy the discharge water quality standards. The surface properties of the TFS were investigated and the anatase crystal structure was observed. It was confirmed that the ratio of Ti and O, the main components of TiO₂, accounted for more than 90 %. As a result of the nitric oxide (NO) reduction experiment, 1.56 uMol of NO was reduced to confirm a removal rate of 20.60 %. This is judged to be a photocatalytic performance similar to that of the existing P-25. Therefore, by applying TiCl₄ to the dyeing wastewater, it is possible to solve the problems of the existing coagulant and to reduce the amount of carbon dioxide generated, using an eco-friendly sludge treatment method. In addition, it is believed that environmental and economic advantages can be obtained by manufacturing TiO₂ at an eco-friendly and lower cost than before.

• Journal of Powder Materials
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• v.24 no.3
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• pp.235-241
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• 2017

Titanium alloys have high specific strength, excellent corrosion and wear resistance, as well as high heat-resistant strength compared to conventional steel materials. As intermetallic compounds based on Ti, TiAl alloys are becoming increasingly popular in the aerospace field because these alloys have low density and high creep properties. In spite of those advantages, the low ductility at room temperature and difficult machining performance of TiAl and $Ti_3Al$ materials has limited their potential applications. Titanium powder can be used in such cases for weight and cost reduction. Herein, pre-forms of Ti-Al-xMn powder alloys are fabricated by compression forming. In this process, Ti powder is added to Al and Mn powders and compressed, and the resulting mixture is subjected to various sintering temperature and holding times. The density of the powder-sintered specimens is measured and evaluated by correlation with phase formation, Mn addition, Kirkendall void, etc. Strong Al-Mn reactions can restrain Kirkendall void formation in Ti-Al-xMn powder alloys and result in increased density of the powder alloys. The effect of Al-Mn reactions and microstructural changes as well as Mn addition on the high-temperature compression properties are also analyzed for the Ti-Al-xMn powder alloys.

• The korean journal of orthodontics
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• v.48 no.3
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• pp.153-162
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• 2018

Objective: The aim of this trial was to compare the alignment efficiency and intermaxillary arch dimension changes of nickel-titanium (NiTi) or copper-nickel-titanium (CuNiTi) round archwires with increasing diameters applied sequentially to the mandibular arch. Methods: The initial alignment phase of fixed orthodontic treatment with NiTi or CuNiTi round archwires was studied in a randomly allocated sample of 66 patients. The NiTi group comprised 26 women, 10 men, and the CuNiTi ($27^{\circ}C$) group comprised 20 women, 10 men. The eligibility criteria were as follows: anterior mandibular crowding of minimum 6 mm according to Little's Irregularity Index (LII), treatment requiring no extraction of premolars, 12 to 18 years of age, permanent dentition, skeletal and dental Class I malocclusion. The main outcome measure was the alignment of the mandibular anterior dentition; the secondary outcome measure was the change in mandibular dental arch dimensions during 12 weeks. Simple randomization (allocation ratio 1:1) was used in this single-blind study. LII and mandibular arch dimensions were measured on three-dimensional digital dental models at 2-week intervals. Results: No statistically significant difference was observed between NiTi and CuNiTi according to LII (p > 0.05). Intercanine and intermolar arch perimeters increased in the CuNiTi group (p < 0.001). Inter-first premolar width showed a statistically significant interaction in week ${\times}$ diameter ${\times}$ application (p < 0.05). Conclusions: The effects of NiTi and CuNiTi round archwires were similar in terms of their alignment efficiency. However, the intercanine and intermolar arch perimeters, and the inter-first premolar width changes differed between groups.

• Journal of the Korean institute of surface engineering
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• v.29 no.4
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• pp.261-267
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• 1996

The characteristics and adhesion strength of TiN layer deposited by D. C. magnetron sputtering were investigated. Three types of TiN layers were deposited on STS304 stainless steel. Scratch tests were performed to determine the effect of deposition temperature, the thickness of coated TiN layer and the titanium inter-layer on the adhesion strength. TiN multilayer with titanium inter-layer showed the highest critical load in the deposition temperature range of $25^{\circ}C$ to $300^{\circ}C$. Adhesion strength of TiN multilayer with titanium inter-layer was raised from 15N to 20N by raising deposition temperature from $25^{\circ}C$ to $400^{\circ}C$. Adhesion strength was raised from 18N to 38N by increasing the thickness of outer layer of TiN multilayer from 2.1 $\mu\textrm{m}$ to 9.5 $\mu\textrm{m}$.