• 연구논문집
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• 통권29호
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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.

• 한국분말재료학회지
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• 제23권4호
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• pp.282-286
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• 2016

A sintered body of $TiB_2$-reinforced iron matrix composite ($Fe-TiB_2$) is fabricated by pressureless-sintering of a mixture of titanium hydride ($TiH_2$) and iron boride (FeB) powders. The powder mixture is prepared in a planetary ball-mill at 700 rpm for 3 h and then pressurelessly sintered at 1300, 1350 and $1400^{\circ}C$ for 0-2 h. The optimal sintering temperature for high densities (above 95% relative density) is between 1350 and $1400^{\circ}C$, where the holding time can be varied from 0.25 to 2 h. A maximum relative density of 96.0% is obtained from the ($FeB+TiH_2$) powder compacts sintered at $1400^{\circ}C$ for 2 h. Sintered compacts have two main phases of Fe and $TiB_2$ along with traces of TiB, which seems to be formed through the reaction of TiB2 formed at lower temperatures during the heating stage with the excess Ti that is intentionally added to complete the reaction for $TiB_2$ formation. Nearly fully densified sintered compacts show a homogeneous microstructure composed of fine $TiB_2$ particulates with submicron sizes and an Fe-matrix. A maximum hardness of 71.2 HRC is obtained from the specimen sintered at $1400^{\circ}C$ for 0.5 h, which is nearly equivalent to the HRC of conventional WC-Co hardmetals containing 20 wt% Co.

• 한국재료학회지
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• 제8권12호
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• pp.1127-1132
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• 1998

본 연구에서는 Al-10wt%Ti-4wt%Fe 복합재료를 in-situ공정으로 제조할 수 있는 가능성 및 2 원계 Al-10wt%Ti 복합재료의 낮은 기계적 성질(탄성계수, 상온 고온강도, 내마모특성 등)을 PM SiC/2124 복합재료 수준 흑은 그 이상으로 향상시킬 수 있는 가능성을 조사하였다. 제조된 Al-10wt%Ti-4wt%Fe 합금은 불연속 SiC 강화상으로 보강된 Al-기지 복합재료($SiC{w}$/2124)와 유사한 미세구조를 보여주었으며, 탄성계수 및 인장강도, 내마모성질 등의 기계적 특성이 2원계 Al-10%Ti 합금각 비교해 현저하게 향상되었음이 관찰되었다. 위의 결과는 초정 $Al_3Ti$상 외에도 Fe 원소의 첨가를 통한 추가적인 $Al_{x}Fe$의 분산강화 효과에 기인한 것으로 해석된다.

• Journal of Magnetics
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• 제14권3호
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• pp.120-123
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• 2009

In this study, BiFe$O_3$-BaTi$O_3$ ceramics have been fabricated by a solid-state reaction method. The effects of BaTi$O_3$ content in the (1-x)BiFe$O_3$-xBaTi$O_3$ (x = 0.1, 0.2, 0.25, 0.3, 0.4, 0.5) system on crystal structure and magnetic, dielectric, and ferroelectric properties were investigated. Perovskite BiFe$O_3$ was stabilized through the formation of a solid solution with BaTi$O_3$. Rhombohedrally distorted structure (1-x)BiFe$O_3$-xBaTi$O_3$ ceramics showed strong ferromagnetism at x = 0.5. Dielectric and ferroelectric properties of the BiFe$O_3$-BaTi$O_3$ system also changed significantly upon addition of BaTi$O_3$. It was found that the maximum dielectric and ferroelectric properties were exhibited in the (1-x)BiFe$O_3$-xBaTi$O_3$ system at x = 0.25. This suggested the morphotropic phase boundary (MPB) with the coexistence of both rhombohedral and cubic phases of the (1-x)BiFe$O_3$-xBaTi$O_3$ system at x = 0.25.

• 한국수소및신에너지학회논문집
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• 제9권2호
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• pp.65-75
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• 1998

실용적인 Fe-Ti계 수소저장합금전극을 제조하기위한 적절한 공정을 확립하기위하여 다섯가지의 서로다른 제조공정을 선택하여 조사하여 보았다. 전극제조를 위해 먼저 FeTi 합금을 플라즈마 아크 용해로에서 용해제조한 후 분쇄하여 분말을 만들고 이를 성형하였다. 성형전에 합금분말을 Ni무전해도금하여 본 결과 Fe-Ti 합금의 방전특성이 개선되었으며 열처리효과에 대하여도 검토하여 보았다. 성형전 합금분말을 열처리하는 경우 열처리 온도가 증가함에 따라 전극의 방전용량이 증가함을 확인하였으며 특히 성형후 $100^{\circ}C$의 온도에서 열처리하는 경우 가장 좋은 결과를 얻을 수 있었다. 이들 결과로 부터, Ni무전해도금과 열처리가 Fe-Ti 계 전극의 방전성능을 향상시키는데 결정적인 역할을 함을 알 수 있었다. 또한, 본 연구에서 제안된 공정에 따라서 Mn을 첨가하여 Fe-Ti-Mn 전극을 제조하고 그 성능을 조사하여 본 결과 대단히 바람직한 결과를 얻었다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.99-102
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• 2009

$TiO_2$ nanotube arraysdecorated with ${\alpha}-Fe_2O_3$ were prepared by forming a nanotube-like $TiO_2$ film on a Ti sheet using an anodization process, followed by electrochemical deposition treatment to decorate hematite (${\alpha}-Fe_2O_3$) nanoparticles on the $TiO_2$ nanotube arrays. The SEM and XRD results revealed that the ${\alpha}-Fe_2O_3$ nanoparticles were homogeneously embedded on the surface of the $TiO_2$ nanotube arrays. The activity of hydrogen production by photocatalytic water decomposition for the ${\alpha}-Fe_2O_3/TiO_2$ nanotube array composite was examined under visible light irradiation.

• Journal of Magnetics
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• 제4권2호
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• pp.65-68
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• 1999

The M-type barium ferrite ($BaFe_{12}O_{19}$) is well known magnetic material to be used as a permanent magnet due to its strong uniaxial anisotropy. The substitution of nonmagnetic $Ti^{+4}$ and magnetically weak $Co+^2ion for Fe^{+3}$ to its strong uniaxial anisotropy. The substitution of nonmagnetic $Ti^{+4}$ and magnetically weak $Co+^2ion for Fe^{+3}$ sublattices reduces the uniaxial anisotropy and those compounds open a new application field of noise suppressor at high frequencies. In this study, the magnetic and microwave absorbing properties are investigated in Ti-and Co-substituted barium ferrites ($BaFe_{12-2X} Ti_XCo_XO_{19}$). The saturated magnetization decreases linearly with the substitution of Ti and Co. The rapid drop in coercive force is observed with Ti and Co substitution upto x=1.2. The magnetic permeability spectrum shows the natural magnetic resonance in the specimens with small coercive force and large attenuation of microwave is predicted in those specimens at high frequencies (above 4 GHz).

• 한국분말재료학회지
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• 제19권2호
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• pp.122-126
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• 2012

The Fe-based self-fluxing alloy powders and TiC particles were ball-milled and subsequently compacted and sintered at various temperatures, resulting in the TiC particle-reinforced Fe self-fluxing alloy hybrid composite, and the microstructure and micro-hardness were investigated. The initial Fe-based self-fluxing alloy powders and TiC particles showed the spherical shape with a mean size of approximately 80 ${\mu}m$ and the irregular shape of less than 5 ${\mu}m$, respectively. After ball-milling at 800 rpm for 5 h, the powder mixture of Fe-based self-fluxing alloy powders and TiC particles formed into the agglomerated powders with the size of approximately 10 ${\mu}m$ that was composed of the nanosized TiC particles and nano-sized alloy particles. The TiC particle-reinforced Fe-based self-fluxing alloy hybrid composite sintered at 1173 K revealed a much denser microstructure and higher micro-hardness than that sintered at 1073 K and 1273 K.

• 한국세라믹학회지
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• 제46권6호
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• pp.621-626
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• 2009

Fe-AC/Ti$O_2$ photocatalysts were prepared by a sol-gel method. The photocatalytic properties of Fe-AC/Ti$O_2$ photocatalysts for the purification of water have been investigated. The samples were characterized by scanning electron microscopy (SEM), specific surface area (BET), X-ray diffraction analysis (XRD), and energy dispersive X-ray spectroscopy (EDX). The photocatalytic activities were evaluated by the photocatalytic oxidation of methylene blue (MB) solution. It was found that the prepared Fe-AC/Ti$O_2$ composites have an excellent photocatalytic under visible light irradiation. A small amount of Fe ions in the AC/Ti$O_2$ composites could obviously enhance their photocatalytic activity. The high activities of the Fe-AC/Ti$O_2$ composites could be attributed to the results of the synergetic effects of the enhancement of the Fe element, the photocatalytic activity of Ti$O_2$, and the adsorption of AC.

• 한국분말재료학회지
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• 제20권3호
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• pp.221-227
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• 2013

$TiB_2$-reinforced iron matrix composite (Fe-$TiB_2$) powder was in-situ fabricated from titanium hydride ($TiH_2$) and iron boride (FeB) powders by the mechanical activation and a subsequent reaction. Phase formation of the composite powder was identified by X-ray diffraction (XRD). The morphology and phase composition were observed and measured by field emission-scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDS), respectively. The results showed that $TiB_2$ particles formed in nanoscale were uniformly distributed in Fe matrix. $Fe_2B$ phase existed due to an incomplete reaction of Ti and FeB. Effect of milling process and synthesis temperature on the formation of composite were discussed.