• Journal of the Korean Ceramic Society
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• v.36 no.5
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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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• v.44 no.4
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• pp.408-415
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• 2009

Iron-loaded activated carbon fibers (Fe-ACF) supported titanium dioxide ($TiO_2$) photocatalyst (Fe-ACF/$TiO_2$) was synthesized using a sol-gel method. Three different types of Fe-ACF/$TiO_2$ were obtained by treatment with different precursor of Fe, and characterized using BET, SEM, XRD and EDX analysis. The photocatalytic activity of Fe-ACF/$TiO_2$ was investigated by the degradation of Rhodamine B (Rh.B) solution under UV irradiation. From the experimental results, it was revealed that Fe-ACF/$TiO_2$ composites show considerable photocatalytic ability for the removal of Rh.B by comparing non-treated ACF/$TiO_2$ composites. And photo-Fenton reaction with Fe element was incoordinately influenced due to different precursor of Fe. It clearly indicates that Fe-ACF/$TiO_2$ composites prepared using $FeCl_3$ provided the highest photo-Fenton activity, then, which was affected by pH changes on the degradation of Rh.B.

• Progress in Superconductivity
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• v.5 no.2
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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.

• Journal of Powder Materials
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• v.23 no.4
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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.

• Journal of Powder Materials
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• v.20 no.3
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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.

• Journal of Korea Foundry Society
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• v.23 no.2
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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.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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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.

• Journal of the Korean Magnetics Society
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• v.5 no.1
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• pp.64-70
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• 1995

The authors have studied crystallographic and magrletic properties of $NdFe_{10.7}TiM_{0.3}(M=B,\;Ti)$ by X-ray diffraction, VSM magnetometer, and Mossbauer spectrometer. The Alloys were prepared by arc-melting under argon atmosphere. The $NdFe_{10.7}TiM_{0.3}$ has pure single phase, whereas the $NdFe_{10.7}Ti_{1.3}$ contains some $\alpha-Fe$, from powder X-ray diffractometry. The $NdFe_{10.7}TiM_{0.3}$ has the $ThMn_{12}$-type tetragonal structure with $a_{0}=8.587\;{\AA}\;and\;c_{0}=4.788\;{\AA}$. The Curie temperature ($T_c$) is $570{\pm}3\;K$ from $M\"{o}ssbauer$ spectroscopy performed at various temperatures ranging from 13 to 770 K. Each spectrum of below $T_c$ was fitted with five subspectra of Fe sites in the structure ($8i_{1},\;8i_{2},\;8j_{1},\;8j_{2}\;and\;8f$). The area fraction of the subspectra at room temperature are 16.4, 8.2, 14.8, 21.3 and 39.3 %, respectively. Magenetic hyperfine fields for the Fe sites decrease in the order, $H_{hf}(8i)>H_{hf}(8j)>H_{hf}(8f)$.

• Journal of Powder Materials
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• v.22 no.3
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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.

• Journal of the Korean Magnetics Society
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• v.2 no.3
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• pp.239-243
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• 1992

It has been found that B is very effective for the increase of magnetization and Curie temperature in $NdFe_{11}TiN_x$-type compounds having $ThMN_{12}$-type structure. Experimental results have shown that magnetization and Curie temperature of $NdFe_{10.7}TiB_{0.3}N_x$ are 148 $Am^2$/kg and $560^{\circ}C,$ respectively, by about 20 $Am^2$/kg and $90^{\circ}C$ higher than those of $NdFe_{10.7}Ti_{1.3}N_x.$ On the other hand, Mo is effective for the increase of anisotropy field, and it seems to strongly inhibit the formation of ${\alpha}-Fe$ phase during the nitrification treatement. The anisotropy field of $NdFe_{10.7}TiMo_{0.3}N_x$ is about 7960 kA/m (100 kOe) which is about 1590 kA/m (20 kOe) higher than that of $NdFe_{10.7}Ti_{1.3}N_x$.