• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.545-546
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• 2006

This study was performed to investigate the surface properties of electrochemically oxidized pure titanium by anodic spark discharging method. Commercially pure titanium plates of $10{\times}20{\times}1[mm]$ in dimensions were polished sequentially emery paper. Anodizing was performed at current density of $76.2\;[mA/cm^2]$, application voltage of 290, 350, 400 [V] using a regulated DC power supply, which allowed automatic transition constant current when a preset maximum voltage has been reached. The Ti surface oxided films was characterized by scanning electron microscope(SEM). The precipitation of HA(Hydroxyapatite) crystals on anodized surface was greatly accelerated by hydrothermal treatment. The concentrations of DL-$\alpha$-Glycerolphosphate Magnesiurn(DL-$\alpha$-GP-Mg) salt and Ca acetate in an electrolyte was highly affected the precipitation of HA crystals converted by Ti Anodized oxide films by Shape of Impulse Voltage.

• 한국정밀공학회지
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• 제28권9호
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• pp.1103-1109
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• 2011

This research quantitatively confirmed an acoustical anisotropy that exists in a pure titanium plate from the signal of ultrasonic flow detection and suggested a new way to evaluate the acoustical anisotropy by inputting acquired characteristic of ultrasound signal into the neutral network. Using the fact with the suggested method that the characteristic of ultrasound signal is shown differently depending on the pure titanium plate's rolling direction, the neural network was constructed by extracting the characteristic that can decide each direction of $0^{\circ}$, $45^{\circ}$, and $90^{\circ}$ with waveform analysis program. As a result of inputting the characteristic of ultrasound signal acquired from a random rolling direction into the neural network that was built like this, it showed a pattern recognition rate higher than 95% on directions of $0^{\circ}$, $45^{\circ}$, $90^{\circ}$.

• 대한치과보철학회지
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• 제35권2호
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• pp.255-264
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• 1997

The conventional osseointegration protocol calls for waiting up to 12 months for ossification of an extraction socket to heal before placing an endosseous implant. In this study, the possibility of placing a pure titanium implant directly into an extraction socket immediately after extraction was investigated. And the marginal bone loss of immediate nonsubmerged and submerged endosseous dental implants placed into extraction sockets was also compared. Pure titanium Nobelpharma Branemark implants and solid screw type ITI implants were placed into premolar extraction sockets of two adult dogs and allowed to heal for a period of 3 months, followed by functional loading of the implant. Radiographic examination was performed before implantation, immediately after implantation and 3, 6, 9, 12 months after implantation. The results obtained were as follows : 1. Immediately placed nonsubmerged ITI implants and submerged Branemark implants showed favorable radiographic osseointegration status and there were minimum marginal bone loss. 2. There were no significant differences in radiographic finding of osseointegration between conventional and immediate implantation. 3. Gingival tissue around implants showed more inflammatory signs than that of adjacent natural teeth. This study suggest that pure titanium Branemark implants and submerged ITI implants have the potential to integrate when placed immediatly after extraction of the teeth and warrants further investigation.

• 한국치위생학회지
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• 제7권4호
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• pp.471-479
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• 2007

The purpose of this study was to examine the optimum condition of impulse during the anodic spark oxidation applying pulse current as well as to find the excellent condition for HA precipitation the after electrochemical hydrothermal treatment by cathode reduction method. After anodic spark oxidation, the anodized specimen and the Pt plate connected cathode and anode, respectively. Hydrothermal treatment performed at 90, 120, $150^{\circ}C$ for 2 hours in the electrolyte containing $K_2HPO_4$, $CaCl_2{\cdot}2H_2O$, Tris(Hydroxymethyl)-$(CH_2OH)_3\;CNH_2$(Aminomethane), and NaCl. The optimum impulse voltage for anodic spark oxidation was 350V. The optimum pulse cycle measured at 10 mS. The HA crystals precipitated excellently by cathode reduction at $150^{\circ}C$ for 2 hours. The phases of anatase, rutile, and HA coating on the surface of modified titanium surface immersed in Hanks' solution for 3weeks were detected by XRD measurement and the intensity of HA crystal phase has increased by temperature and time of hydrothermal treatment. According to the our experiments, we found that Pure Ti will be good materials of bioactivity and biocompatibility.

• 한국세라믹학회지
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• 제45권11호
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• pp.688-693
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• 2008

This paper presents a study on the photocatalytic reaction about the composite particles of $TiO_2$-coated phosphors under visible light irradiation. Nanocrystalline titanium dioxide layers were directly coated on the alkaline earth aluminate phosphor, $CaAl_2O_4:Eu^{2+},\;Nd^{3+}$ particles by an sol-gel processing method. The photocatalytic reaction was analyzed with the degradation of methylene blue (MB) aqueous solution under UV and visible light irradiations. $TiO_2$-coated phosphor powders showed different photocatalytic mechanism, compared with pure $TiO_2$ (P-25, Degussa). Under UV-irradiation, $TiO_2$-coated phosphor powders showed slow photocatalytic reactivity in the early stage and fast in the latter, compared with that of pure $TiO_2$. However, $TiO_2$-coated phosphor powders showed much faster photocatalytic reactivity than that of pure $TiO_2$ under visible irradiation. In addition, the characterizations of the $TiO_2$-coated phosphor powders were conducted by a X-ray diffractometer (XRD), transmission electron microscope (TEM), and energy dispersive spectroscopy (EDS).

• Journal of Welding and Joining
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• 제34권6호
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• pp.69-74
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• 2016

Because the pure titanium has superior corrosion resistance and formability compared with different material, it is widely used as material of welded heat exchanger. When the welding of heat exchanger is carried out, certain area in which welding start and end are overlapped occurs. The humping of back bead is formed in the overlap area due to partial penetration. Thus in this study, the experiments were carried out by changing the length and wave shape of overlap area, and then the weldabiliay was evaluated through the observation of microstructure, the measurement of hardness and tensile-shear strength test in the overlap area. When overlap length was 9.8mm, humping bead was suppressed. The microstructure of overlap area coarsened and its hardness increased due to remelting. As a result of tensile-shear strength test in the overlap area according to applying the wave shape control, it was confirmed that the overlap area applied wave shape control had more excellent yield strength and ductility.

• 한국결정성장학회지
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• 제20권2호
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• pp.80-84
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• 2010

The temperature-programmed reduction of titanium oxide ($TiO_2$) with pure $CH_4$ was used for the preparation of titanium carbide crystallites. The synthesized materials had the different surface areas, indicating that the structural properties of these materials were strong functions of two different heating rates and space velocity employed. The titanium carbide crystallites were active for $NH_3$ decomposition. Since the reactivity varied with changes in the particle size, ammonia decomposition reactivity over the titanium carbides crystallites appeared to be related to the different active species. The reactivities of titanium carbide crystallites were two and three times lower than those of the vanadium and molybdenum carbide crystallites, respectively. These results suggested that the difference in activities might be related to the degree of electron transfer between metals and carbon.

• Fibers and Polymers
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• 제5권2호
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• pp.105-109
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• 2004

The synthesis of titanium dioxide nanofibers with 200-300nm diameter was presented. The new inorganic-organic hybrid nanofibers were prepared by sol-gel processing and electrospinning technique using a viscous solution of titanium isopropoxide (TiP)/poly(vinyl acetate) (PVAc). Pure titanium dioxide nanofibers were obtained by high temperature calcination of the inorganic-organic composite fibers. SEM, FT-IR, and WAXD techniques were employed to characterize these nanofibers. The titanium dioxide nanostructured fibers have rougher surface and smaller diameter compare with PVAc/TiP composite nanofibers. The anatase to rutile phase transformation occurred when the calcination temperature was increased from $600^{\circ}C$ to $1000^{\circ}C$.

• 한국세라믹학회지
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• 제31권5호
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• pp.561-571
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• 1994

For the preparation of SiC composite, the properties of reaction sintering in the SiC-C-Si-Ti system with the titanium contents variation were investigated. Either the case of titanium additions or the case of direct infiltration of titanium in SiC+C preform, the newly formed fine-grained $\beta$-SiC, which was reacted from the molten silicon with graphite, was intergranulated between the original $\alpha$-SiC particles. Also titanium disilicide (TiSi2) was discontinuously formed isolated pocket in silicon matrix. The amount of titanium disilicide was gradually increased as titanium content increase. With the results of hardness and fracture toughness measurement, SiC-titanium disilicide (TiSi2) composite represented high properties compared with the system of the infiltrated pure silicon.

• 한국표면공학회지
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• 제35권5호
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• pp.273-278
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• 2002

We oxidized pure titanium by anodizing oxidation process in the range of 590V, within 1.5A, 30seconds. we investigated color evolution with a spectrophotometer. Surface images and surface roughness were characterized by an optical microscope and an atomic force microscope, respectively. Below the thickness of 40 $\mu\textrm{m}$, metallic yellow, blue, and pink colorsn were obtained. Lightness decreased, increased, and decreased again as titanium oxide thickness increased. Blue color at the applied voltage of 30V showed the best lightness and reproducibility with surface roughness below l$\mu\textrm{m}$. Bare titanium and titanium oxide films had micro pits more than 10ea/$\mu\textrm{m}^2$. We report that we successfully made colors by varing thickness below 40$\mu\textrm{m}$ with anodizing oxidation of method.