• Journal of Periodontal and Implant Science
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• v.26 no.1
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• pp.143-160
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• 1996

The purpose of this study was to evaluate the response in aspect of attachment and growth rate of osteoblasts and growth rate of osteoblasts and human gingival fibroblasts to the commercially pure titanium(CP titanium)and titanium alloy(Ti-6AI-4V) that are used widely as implant materials, and to obtain the basic information to ideal implant materials. In the studly, commercially pure titanium in first test group, titanium alloy(Ti-6AI-4V) in second test group, cobalt-chrome-molybdenum alloy(Co-Cr-Mo alloy) in positive control group, and tissue culture polystyrene plate in negative control group were used. The results of this study were as follows. 1. Bone marrow cells cultured on CP titanium and Ti-6Al-4V showed significantly greater attachment and growth rate(p(0.05) compared to Co-Cr-Mo alloy in each time. 2. There were no significant differences(p>0.05) in attachment and growth rate of bone marrow cells cultured on CP titanium and Ti-6AI-4V or tissue culture plate. 3. Most bone marrow cells cultured on CP titanium, Ti-6Al-4V and tissue culture plate were attached well to each substratum in first 2days, and then, grew at higher growth rate. On the other hand, some cells cultured on Co-Cr-Mo alloy failed to attach in first 2 days, and then, attached cells grew at lower growth rate than other groups. 4. Attachment and growth rates of gingival fibroblasts cultured on CP titanium and Ti-6Al-4V showed no significant differences(p>0.05) compared to Co-Cr-Mo alloy in 2 days, but significantly greater increase(p<0.05) in 5 and 9 days. 5. There were no significantly differences(p>0.05) between growth rates on gingival fibroblasts cultured on CP titanium, Ti-6Al-4V and tissue culture plate in 2 and 5days, but a significant lower growth rate(p<0.05) on CP titanium and Ti-6Al-4V versus tissue culture plate. 6. Some gingival fibroblasts cultured on all specimen groups failed to attach, but attached cells grew well, especially on CP titanium, Ti-GAl-4V and tissue culture plate. 7. There were no significant differences(P>0.05) between growth rates of both bone marrow cells and gingival fibroblasts cultured on CP titanium and Ti-6AI-4V. As a result of this study, both commercially pure titanium and Ti-6AI-4V showed excellent biocompatibility and there was no significant difference in the cellular response to the both metals. Bone marrow cells cultured on each substratum showed significantly greater growth rate and responded sensitively to cytotoxic effects of metal surfaces compared to gingival fibroblasts. Considering cell response to the substrate, it was likely that the composition itself of titanium metals have no significant effect on the biocompatibility. Further study need to be done to evaluate the influence of surface characteristics on cellular responses.

• Journal of Powder Materials
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• v.17 no.5
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• pp.385-389
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• 2010

Titanium powders have been usually produced by de-hydrogenating treatment in vacuum with titanium hydride ($TiH_2$) powders prepared by milling of hydrogenated sponge titanium, $TiH_x$. The higher stoichiometry of x in $TiH_x$, whose maximum value is 2, is achieved, crushing behavior is easier. $TiH_x$ powder can be, therefore, easy to manufactured leading to obtain higher recovery factor of it. In addition, contamination of the powder can also minimized by the decrease of milling time. In this study, the hydrogenation behavior of sponge titanium was studied to find the maximum stoichiometry. The maximum stoichiometry in hydride formation of sponge titanium could be obtained at $750^{\circ}C$ for 2 hrs leading to the formation of $TiH_{{\sim}1.99}$ and the treating temperatures lower or higher than $750^{\circ}C$ caused the poor stoichiometries by the low hydrogen diffusivity and un-stability of $TiH_x$, respectively. Such experimental behavior was compared with thermodynamically calculated one. The hydrogenated $TiH_{1.99}$ sponge was fully ball-milled under -325 Mesh and the purity of pure titanium powders obtained by de-hydrogenation was about 99.6%.

• Transactions of Materials Processing
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• v.8 no.3
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• pp.259-259
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• 1999

TiC ceramic particulate-reinforced titanium matrix composites were fabricated and the resultant densification, microstructure, and static and dynamic mechanical properties were studied. Comparing Ti with TiH₂powders as host materials for TiC ceramic reinforcement by pressureless vacuum sintering, TiH₂-started composites showed better sinterability and resistance to both elastic and plastic deformation than Ti-started ones. When TiH₂and TiH₂-45 vol.%TiC samples were hot pressed, TiH₂matrices transformed to alpha prime Ti and alpha Ti phase, respectively. It is interpreted that the diffusion of an alpha stabilizer carbon from TiC into the matrix is one of the plausible reasons far such a microstructural difference. The 0.2% offset yield strengths of the hot pressed TiH₂and TiH₂-45 vol.%TiC samples were 1008 and 1446 MPa, respectively, in a static compressive mode (strain rate of 1×$10^{-3}$/s). Dynamic compressive strengths of the samples were 1600 and 2060 MPa, respectively, at a strain rate of 4×10³/s.

• Korean Journal of Metals and Materials
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• v.50 no.10
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• pp.745-751
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• 2012

The Kroll process for magnesium reduction of titanium tetrachloride is used for mass production of titanium sponge. The present study was conducted in a lab scale reactor to develop a better understanding of the mechanism of titanium sponge formation in the Kroll reactor with respect to reaction degrees and the feeding rate of $TiCl_4$. The $MgCl_2$ produced during the initial stage of the reaction was not sunk into the molten magnesium, but covered the surface of the molten magnesium. As a result, subsequently fed $TiCl_4$ reacted with Mg exposed on the edge of molten $MgCl_2$ in the crucible. Therefore, titanium sponge grew toward the center of the crucible from the edge. The temperature of the molten magnesium increased remarkably with the increasing feeding rate of $TiCl_4$. Consequently, fed $TiCl_4$ reacted at the upper side of the crucible with evaporated Mg, and produced titanium on the upper surface of the crucible wall, which increased considerably with the feeding rate of $TiCl_4$.

• Journal of the Korean Ceramic Society
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• v.23 no.6
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• pp.33-36
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• 1986

The $PbTiO_3$is well known materials having remarkable ferroelectric piezoelectric and pyro-electric properties. Thin films of the lead titanite has been successfully fabricated by Chemical Vapor Deposition on the borosilicate glass and titanium substrate. The $PbTiO_3$ thin film deposited on the borosilicate glass using the $PbCl_2$, $TiCl_4$ dry oxygen and wet oxygen at different temperatures (50$0^{\circ}C$-$700^{\circ}C$) grows along the (001) preferred orientation. On the other hand the $PbTiO_3$ thin film deposited on the titanium substrate using the PbO grows along the (101) preferred orientation. Growth orientation of deposited $PbTiO_3$ depends on the reaction species irrespective of substrate materials. Maximum dielectic constant and loss tangent of the $PbTiO_3$ thin film deposited on the titanium substrate are about 90 and 0.02 respectively, . Deposition rates of $PbTiO_3$ deposited on the borosilicate glass and titanium substrate are 10-15 ${\mu}{\textrm}{m}$/hr. Titanium dioxide interlayer formed be-tween $PbTiO_3$ film and titanium substrate material, It improved the adhesion of the film.

• Korean Journal of Metals and Materials
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• v.47 no.3
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• pp.182-187
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• 2009

The molten salt electrolysis is applied to reduce titanium dioxide to titanium metal using calcium chloride as an electrolyte and the reaction mechanism of the reduction process is examined by analyzing the reaction products. The process conditions to obtain titanium metal for $900^{\circ}C$ correspond to 2.9~3.2 V and 24 hours. The reaction products for 2.9 V at $900^{\circ}C$ include irregular-shaped titanium oxides such as $Ti_4O_7$, $Ti_3O_5$ and $Ti_2O_3$ and polyhedral $CaTiO_3$. Using these microstructure analysis, the sequential reaction mechanism for the electrochemical reduction of titanium dioxide to titanium is proposed.

• Korean Journal of Materials Research
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• v.9 no.8
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• pp.787-791
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• 1999

TiB$_2$powders were prepared by mechanical alloying, and the effect of Zr and Ta substitution for Ti was investigated. It was possible to produce titanium diboride phase by mechanical alloying titanium and boron elemental powders for 280 hours. The amorphization reaction, a common process which occurs during mechanical alloying, has not been found. When zirconium of which atomic radius was larger than that of titanium was substituted for Ti, the alloying time was greatly reduced. On the contrary, substitution of tantalum for titanium prolonged the alloying time because of the less negative heat of formation of tantalum diboride than that of titanium diboride.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.152-157
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• 2009

Titanium alloy sheets have excellent specific strength and corrosion resistance as well as good performance at high temperature. Recently, titanium alloys are widely employed not only aerospace parts but also bio prothesis and motorcycle. But the database is insufficient of the titanium alloy for press forming process. In this study, the effect of temperature on the forming limit diagram was investigated for Ti-6Al-4V titanium alloy sheet through the Hocker's punch stretching test at elevated temperature. Experimental results obtained in this study can provide a database for development of press forming process at elevated temperature of Ti-6Al-4V titanium alloy sheet. From the experimental studies it can be concluded that the formability of Ti-6Al-4V titanium alloy sheet is governed by the ductile failure for the testing temperature below and vice versa neck-induced failure above the recrystalization temperature $0.5T_m$. The formability of Ti-6Al-4V titanium alloy sheet at $750^{\circ}C$ increases about 7 times compared with that at room temperature.

• 연구논문집
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• s.29
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• pp.163-171
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• 1999

A new titanium alloy system. Ti-xFe-ySi (x,y=0-4 wt%). was designed and characterized with the point at low cost and high strength for casting applications. Fe improved room and elevated temperature mechanical properties owing to solid solution hardening and beta phase stabilization. Si yielded titanium silicides and Si addition over 1 wt% resulted in poor ductility due to coarse silicide chains at prior beta boundaries. The optimum composition was found to be Ti-4Fe-(0.5-1)Si in the viewpoint of tensile strength and ductility which are comparable to the Ti-6Al-4V. The metal-mould reaction was also examined for Ti-xFe and Ti-xSi binary alloy system. The thickness of surface reaction layer w as not affected significantly with Fe content, while it was decreased with Si content. In the Ti-4Si alloy, no reaction layer was found. The depth of surface hardening layer was about $200\mum$ regardless of the mould materials.

• Journal of Powder Materials
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• v.17 no.2
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• pp.123-129
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• 2010

The fabrication of interconnect from titanium powders and $TiN_x$ powders is investigated. Corrosion-resistant titanium and $TiN_x$ are used as reinforcement in order to reveal high heat and corrosion resistance at the elevated temperature. We fabricated the plates for interconnect reinforced with $TiN_x$ by mixing titanium powders with 10 wt.% of nano-sized $TiN_x$. Spark Plasma Sintering (SPS) was chosen for the sintering of these composites. The plate made of titanium powders and $TiN_x$ powders demonstrates higher corrosion resistance than that of the plate of titanium powders alone. The physical properties of specimens were analyzed by performing hardness test and biaxial strength test. The electrochemical properties, such as corrosion resistance and hydrogen permeability at high temperature, were also investigated. The microstructures of the specimens were investigated by FESEM and profiles of chemical compositions were analyzed by EDX.