• 한국세라믹학회지
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• 제36권5호
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• pp.471-477
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• 1999

Fe and Fe-Mo binder were used to produce TiB2 based cermet by a pressureless sintering. The densification behaviour of TiB2-Fe-Mo cermet during liquid-phase sintering in argon was studied in relation to binder phase charactertics. The effects of Mo addition and sintering condition on the sintering behaviour and mechanical properties were also investigated. TiB2-based cermets with Fe-Mo binder composition showed a better sinterability than the cermets with only Fe binder. In TiB2-Fe-Mo cermet higher densities in the wide temperature range were obtained and also fully densified sintered cermet were obtained at 1873K The enhancement in the densification phenomenon of TiB2-Fe-Mo system can be explained by improved liquid phase wettability associated with the roles of Mo components as solute atoms. When Fe-Mo binders were used cermets with a finer grain size and enhanced mechanical properties wereproduced and new phases such as Fe2B and Mo2FeB2 were observed in the sintered cermet. The highest bending strength was obtained from the 20vol% Fe-Mo cermet and these hardness-fracture toughness combination in the wide binder compositions is better than that of TiB2-Fe cermet. In order to improve mechanical properties microstructure control with high purity powders is desirable because high purity powders prevent the formation of Fe2B and Mo2FeB2 phase which comsume the ductile binder phase.

• Elastomers and Composites
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• 제44권4호
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• pp.408-415
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• 2009

졸-겔 방법을 사용하여 Fe-ACF/$TiO_2$ 복합체 광촉매를 제조하였다. 여러 가지 철 전구체를 사용하여 세가지 Fe-ACF/$TiO_2$ 복합체를 제조하고 BET, SEM, XRD 및 EDX를 사용하여 특성화 하였다. UV 조사에서 Rh.B 용액의 분해에 의거하여 Fe-ACF/$TiO_2$ 복합체의 광촉매 특성을 파악 하였다. 실험 결과로부터, Fe-ACF/$TiO_2$ 복합체는 ACF/$TiO_2$ 복합체 보다 Rh.B의 제거 효과가 더 우수함을 나타내었다. 또한 여러 가지 Fe 전구체 사용으로 인한 Fe 원소의 포토-펜톤 효과는 다르게 나타났다. $FeCl_3$을 사용하여 제조된 Fe-ACF/$TiO_2$ 복합체는 가장 우수한 포토-펜톤 효과를 나타내었고, pH 변화에 의존하여 Rh.B 용액 분해에 대하여 영향을 주었다.

• Progress in Superconductivity
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• 제5권2호
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• pp.109-113
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• 2004

MgB$_2$ and FeTi composites was prepared to study the effect of FeTi particles on superconductivity of MgB$_2$. The sample, which had contained magnesium, boron and FeTi particles, was synthesized by the Commercial Stainless Steel Tube Enveloping Technique(COSSET) at 92$0^{\circ}C$ for 2 hours. The structure and properties of the sample was investigated by XRD, SEM, and SQUID magnetometer. It was found that there was a little change of T$_{c}$ compared with pure MgB$_2$ superconductor in spite of high percentage of FeTi particles, and there was no proof of structure change of MgB$_2$ superconductor due to FeTi particles. But the high porosity which was appeared in the pure MgB$_2$ was disappeared in the composites. We conclude that FeTi particles do not influence the superconductivity of MgB$_2$ and it is expected that fe-Ti material system will be a good material for a tube of the PIT process and for a substrate of the film.m.

• 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.

• 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.

• 한국주조공학회지
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• 제23권2호
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• pp.77-85
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• 2003

Some alloying elements such as Cr, B, Ti and Si were added individually or as a mixture to Fe-30 at.%Al alloys. The alloys were melted using an arc furnace and then heat-treated for homogenization at 1000$^{\circ}C$ for 7 days and followed by rolling at 1000$^{\circ}C$. The alloying elements on rolling characteristics were investigated by the microstructures and fracture mode before and after rolling. The microstructures before rolling showed that all of the alloys had equiaxed grains. On the other hand, the microstructures of rolling plane as well as its perpendicular plane became elongated after rolling. The alloys such as Fe-30Al, Fe-30Al-3Ti, Fe-30Al-0.5B, Fe-30Al-5Cr and Fe-30Al-3Ti-0.5B revealed better rolling behaviour from the point that intergranular and cleavage fractures were not fundamentally occurred. But the addition of 5Ti or 3Si to Fe-Al alloys had detrimental effects. The Ti-added alloy system such as Fe-30Al-5Ti, Fe-30Al-5Ti-5Cr, Fe-30Al-3Ti-5Cr and Fe-30Al-5Ti-0.5B were cracked through grain and showed cleavage fracture. The Si-added alloy system such as Fe-30Al-5Si, Fe-27Al-3Si and Fe-27Al-5Cr-3Si were cracked along the grain boundary and showed intergranular fracture. $DO_3{\leftrightarrow}B_2$ transition temperature of Fe-30at.%Al alloy was 520$^{\circ}C$, whereas the addition of 3Ti and 3Ti+0.5B comparably increased the temperature to 797 and 773$^{\circ}C$, respectively.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.91.2-91.2
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• 2012

The TiB2-reinforced iron matrix nanocomposite (Fe-TiB2) was in-situ fabricated from titanium hydride (TiH2) and iron boride (FeB) powders by a simple and cost-effective process that combines the mechanical activation (MA) and a subsequent heat treatment (HT). Effect of milling factors and synthesized temperatures on the formation of the nanocomposite were presented and discussed. A differential thermal analyser (DSC-TG) was employed for examination of thermal behavior of MAed powders. Phases of the nanocomposite were confirmed by X-ray diffraction analysis (XRD). The morphologies and microstructure of nanocomposite were investigated by field emission-scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDS). Phase composition and distribution were analyzed by electron probe X-ray microanalysis (EPMA). Results showed that TiB2 particles formed in nanoscale were uniformly distributed in alloyed Fe matrix.

• 한국자기학회지
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• 제5권1호
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• pp.64-70
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• 1995

$ThMn_{12}$ 구조를 갖는 $NdFe_{10.7}TiM_{0.3}(M=B,\;Ti)$의 결정학적 및 자기적 성질을 X선 회절법과 VSM, $M\"{o}ssbauer$분광법으로 연구하였다. $NdFe_{10.7}TiM_{0.3}(M=B,\;Ti)$합금은 알곤가스 분위기의 아크 용해로에서 제조하였다. $NdFe_{10.7}TiM_{0.3}$의 결정구조는 순수 단일상의 tetragonal구조를 갖고 있으며 $a_{0}=8.587\;{\AA},\;c_{0}=4.788\;{\AA}$의 격자상수를 결정하였다. $M\"{o}ssbauer$ spectrum은 13 K 부터 770 K 영역까지 취하였으며 Curie 온도는 $NdFe_{10.7}TiM_{0.3}$의 경우 $570{\pm}3\;K$로 결정하였다. $NdFe_{10.7}TiM_{0.3}(M=B,\;Ti)$은 $8i_{1},\;8i_{2},\;8j_{1},\;8j_{2}$ 및 8f의 5 set의 Fe 이온의 subspectra로 분석하였다. $NdFe_{10.7}TiM_{0.3}$의 실온에서 Fe-site $8i_{1},\;8i_{2},\;8j_{1},\;8j_{2}$ 및 8f는 16.4, 8.2, 14.8, 21.3 및 39.3%의 면적비를 각각 가지고 있었다. 초미세자기장은 $H_{hf}(8i)>H_{hf}(8j)>H_{hf}(8f)$비로 감소함을 알았다.

• 한국분말재료학회지
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• 제22권3호
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• pp.208-215
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• 2015

Fe-TiC composite powders were fabricated by planetary ball mill processing. Two kinds of powder mixtures were prepared from the starting materials of (a) (Fe, TiC) powders and (b) (Fe, $TiH_2$, Carbon) powders, respectively. Milling speed (300, 500 and 700 rpm) and time (1, 2, and 3 h) were varied. For (Fe, $TiH_2$, Carbon) powders, an in situ reaction synthesis of TiC after the planetary ball mill processing was added to obtain a homogeneous distribution of ultrafine TiC particulates in Fe matrix. Powder characteristics such as particle size, size distribution, shape, and mixing homogeneity were investigated.

• 한국자기학회지
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• 제2권3호
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• pp.239-243
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• 1992

$ThMN_{12}$ 구조를 갖는 $NdFe_{11}TiN_x$ 형 화합물에서 B 이 자화 및 큐리온도의 상승에 매우 효과적임이 밝혀졌다. $NdFe_{10.7}TiB_{0.3}N_x$ 의 자화 및 큐리온도는 $NdFe_{10.7}Ti_{1.3}N_x$ 의 경우에 비하여 각각 20 $Am^2$/kg (20 emu/g) 및 $90^{\circ}C$가 높은 148 $Am^2$/kg (148 emu/g) 및 $560^{\circ}C$를 나타내었다. 한편, Mo은 이방성자장의 증가에 효과적이며, 또한, 질화처리시 ${\alpha}-Fe$의 생성 억제에 효과적인 것으로 추측된다. $NdFe_{10.7}TiMo_{0.3}N_x$ 의 이방성자장은 약 7960 kA/m (100 kOe) 로 $NdFe_{10.7}Ti_{1.3}N_x$ 의 경우에 비하여 약 1590 kA/m (20 kOe) 가 증가한 결과를 보였다.