• Journal of the Korean Ceramic Society
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• v.32 no.1
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• pp.37-44
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• 1995

TiO2 fine powders were synthesized using oxygenolysis and hydrolysis reaction of TiCl4 vapor in gas phase. The TiO2 powder synthesized showed morphological differences depending on reaction system as follows: TiCl4-O2 reaction system produced the monosized particles having polyhedral shape with well-defined crystal planes and the particles did not agglomerate into secondary particles. TiCl4-H2O reaction system, whereas, produced the spherical secondary particles which consisted of fine primary particles. Other powder characteristics such as particle size, impurity content and rutile content are also reported in this study.

• 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.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2005.11a
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• pp.36-36
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• 2005

• Journal of Powder Materials
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• v.6 no.1
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• pp.75-80
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• 1999

The formation of $n-TiO_2$ powder by oxidation of Ti-ethoxied vapor in a flat flame burner reactor maintained under 20 torr has been studied. The produced powder were characterized in terms of crystal structure, chemical composition by XRD and TEM. The results showed that the powder consisted of loose agglomerated anatase and rutile particles and their size were about 10 nm and 20 nm, respectively. In the course of synthesis, changes of the flame color were happened to each condition during heating up the bubbler. The flame color transition phenomena reveled that a critical precursor delivery rate was needed for the powder formation (obtainable powder yield). The critical precursor delivery rate was estimated by a simple function of the bubbler temperature and the carrier gas flow rate. The critical precursor delivery rate was reviewed as an important variable of the nanopowder synthesis.

• Journal of the Korean Ceramic Society
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• v.30 no.3
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• pp.222-228
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• 1993

In order to obtian TiO2 fine powder of high purity, the new method which is different from the sulfate process and the chloride one was employed. TiO2 was syntehsized by the reaction between elemental titanium particles and H2O2 solutiosn at 30~7$0^{\circ}C$, and then TiO2 powder was characterized using XRD, SEM, TEM, DTA and FT-IR. It was found that the initial reaction rate was fast at a high temperature due to the high generation of activated oxygen associated with thedecomposition of H2O2. However, the reaction was slowly proceeded at a low temperature due to slow decomposition of H2O2. In this experimental range, the optimum temeprature was ocnsidered to be about 5$0^{\circ}C$. The primary particles of the hydrous titanium dioxide (TiO2 gel) before aging were spherical, and their mean sizes were about 50nm. The similar shapes and sizes were observed with calcinatin at 40$0^{\circ}C$. The FT-IR spectrum of Ti-OH in the TiO2 gel powder appeared at around 3380cm-1, 1630cm-1 and 530cm-1. This gel powder was crystallized into the anatase type TiO2 at 300~40$0^{\circ}C$.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1152-1153
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• 2008

본 연구에서는 Ketjen black을 이용한 DSCs (Dye-sensitized solar cells)용 다공질의 $TiO_2$ nano-powder 제작기술을 제안한다. $TiO_2$ powder는 sol-gel법에 의해 Ti-isopropoxide와 2-propanol을 사용하여 제작되었으며, Ketjen black의 함량(0g$\sim$2g)을 달리하여 제작된 $TiO_2$ nano-powder의 다공성과 입자의 크기, 결정성등의 특성을 고찰하였다. 또한 이러한 $TiO_2$ powder를 paste로 만들어 다른 열처리 온도($100^{\circ}C{\sim}600^{\circ}C$)에서 $TiO_2$ 박막을 이용한 DSCs를 제작한 후 그 효율을 측정하였다. 그 결과 Ketjen black 1g을 함유시켜 만들어진 $TiO_2$ powder의 다공성과 입자 크기가 가장 우수한 것으로 FE-SEM의 측정결과 나타났으며, 500$^{\circ}C$의 열처리 공정을 거쳐 제작된 셀의 효율이 가장 높은 효율인 5.46%를 나타내고 있음을 확인할 수 있었다.

• Journal of Powder Materials
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• v.14 no.3 s.62
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• pp.208-214
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• 2007

The microstructure and hardness of (W,Ti)C cemented carbides with a different metallic binder composition of Ni and Co fabricated by powder technology were investigated. The densifications of the prepared materials were accomplished by using vacuum sintering at $1450^{\circ}C$. Nearly full dense (W,Ti)C cemented carbides were obtained with a relative density of up to 99.7% with 30 wt.% Co and 99.9% with 30 wt.% Ni as a metallic binder. The average grain size of the (W,Ti)C-Co and the (W,Ti)C-Ni was decreased by increasing the metallic binder content. The hardness of the dense (W,Ti)C-15 wt%Co and (W,Ti)C-15 wt%Ni, was greater than that of the other related cemented carbides; in addition, the cobalt-based cemented carbides had greater hardness values than the nickel-based cemented carbides.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.2
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• pp.322-326
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• 2009

In this work, nanoporous $TiO_2$ powder was fabricated using Ketjen black, and applied in photovoltaic device based on the Dye-sensitized Solar Cells (DSCs). $TiO_2$ powder was fabricated using Ti-isopropoxide and 2-propanol by sol-gel combustion method. For added $0{\sim}2g$ variable of Ketjen black, characteristic of porosity, size of particle and crystallite of obtained $TiO_2$ nano powder was investigated. The photovoltaic efficiency of the prepared DSCs was measured using $TiO_2$ film which prepared on each different heat treatment temperature($100^{\circ}C{\sim}600^{\circ}C$) with paste of $TiO_2$ powder. The porosity and size in particle of $TiO_2$ powder made with Ketjen black Ig was influenced significantly effect to DSCs characteristic. Heat treatment at $500^{\circ}C$ makes the better photovoltaic efficiency which around 6.11%($J_{sc}=13.35mA/cm^2$, $V_{oc}=0.73V$, ff=0.63). The sol-gel combustion method was useful to DSCs fabrication.

• Journal of Powder Materials
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• v.8 no.4
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• pp.223-230
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• 2001

Ti-37.5at%Si elemental powder mixtures were mechanically alloyed by a high-energy ball mill, followed by CIP (cold isostatic pressing) and HIP (hot isostatic pressing) for different processing conditions. Only elemental phases (Ti and Si) were observed for the 5 min mechanically alloyed (MA 5 min) powder, but only $Ti_5Si_3$phase was observed for the 30 min mechanically alloyed (MA 30 min) powder. $Ti_5Si_3$phase was observed for the HIPed compact of MA 5 min and 30 min powders at 150 and 190 MPa for 3 hr at $1000^{\circ}C$. For the HIPed compacts, the highest sintered density was obtained to be 99.5% of theoretical density by a HIP step at $1350^{\circ}C$ at 190MPa for 3hr. The hardness values of the HIPed $Ti_5Si_3$compacts at $1350^{\circ}C$ at 150/190 MPa for 3hr were higher than HRC 76. The densification and mechanical property of HIPed $Ti_5Si_3$compacts was found to depend on more HIP temperature than HIP pressure.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1998.10b
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• pp.16-16
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• 1998