• 한국전기화학회:학술대회논문집
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• 2005.07a
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• pp.335-340
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• 2005

Amorphous $MgNi_{1-x}Ti_x$ alloys with the composition of x=0.02, 0.03, 0.05 and 0.07 were synthesized by mechanical alloying. The synthesized alloys were investigated by electrochemical test, XRD and SEM. As increasing Ti concentration, the initial discharge capacity was raised more than that of nanocrystalline Mg-Ni 289 mAh/g, but the electrodes were degraded faster. Comparing to other synthesized alloys, $MgNi_{0.95}Ti_{0.05}$ alloy showed the highest initial discharged capacity 474 mAh/g and maintained $54\%$ of the initial capacity after 10 cycles.

• Transactions of the Korean hydrogen and new energy society
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• v.10 no.1
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• pp.1-7
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• 1999

In order to study on the effect of fabrication methods on the changes of hydrogenation properties of FeTi alloy, FeTi samples were prepared using three different methods, i.e., arc melting, mechanical alloying and combination of the two methods. The FeTi prepared by mechanical alloying represented amorphous structure. The hydrogen storage capacity of arc melted FeTi alloy is larger than any other samples. However, FeTi electrode fabricated by mechanical alloying after arc melting showed largest discharge capacity among them.

• Journal of Advanced Marine Engineering and Technology
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• v.18 no.5
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• pp.29-35
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• 1994

The microstructual refinement process of Al-5Cr-2Zr alloys mechanical alloying 30h can be divided in five stages ; initial stage, welding predomminance stage, spherical partical formation stage, convolution welding predominance stage, and steady state. The rate of structural of aluminium splats was roughly logarithmic with processing time ; ${\in}$=k/0.78 ln(1+0.0028t). The age hardening in rapidly solidified Al-5Cr-2Zr alloys is ascribed to the coherency and dispersion hardening. Coherency hardening is occurred by matastable cubic Al3Zr precipitates in Al-Cr-Zr alloys. Dispersion hardening after mechanical alloying is attributed to the finely-dispersed $Al_2O_3$ and $Al_4C_3$ in Al-5Cr-2Zr alloys.

• Korean Journal of Materials Research
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• v.13 no.1
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• pp.24-30
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• 2003

The Raney Ni catalyst was fabricated by mechanochemically process(MC process) in the Al-Ni system. Intermetallic compound obtained by mechanical alloying was leached in an alkaline solution. The characteristics of the mechanically alloyed powder and Raney Ni catalyst were analyzed by XRD, ICP-AES and EXAFS. In Al-50wt.%Ni, the metastable intermetallic compound phase close to AlNi phase was obtained by mechanical alloying unlike Al-Ni equilibrium phase diagram. The metastable intermetallic compound was transformed into $Al_3$$Ni_2$phase via the annealing at $750^{\circ}C$. The microstructure of Raney Ni fabricated by MC process was mainly bcc Ni including fcc Ni.

• Journal of Powder Materials
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• v.4 no.2
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• pp.122-132
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• 1997

Nanostructured(NS) W-Cu composite powders of about 20~30 nm grain size were synthesized by mechanical alloying. The properties of NS W-Cu powder and its sintering behavior were investigated. It was shown from X-ray diffraction and TEM analysis that the supersaturated solid solution of Cu in W was not formed by the mechanical alloying of mixed elemental powders, but the mixture of W and Cu particles with nanosize grains, i.e., the nanocomposite powder was attained. Nanocomposite W-20wt%Cu and W-30wt%Cu powders milled for 100 h were sintered to the relative density more than 96% and 98%, respectively, by sintering at 110$0^{\circ}C$ for 1 h in $H_2$. Such a high sinterability was attributed to the high homogeneous mixing and ultra-fine structure of W and Cu phases as well as activated sintering effect by impurity metal introduced during milling.

• Journal of Powder Materials
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• v.2 no.2
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• pp.165-170
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• 1995

Alloying behavior of nanocrystalline Al-Ti-(Si) composite powders via mechanical alloying (MA) has been investigated, and the effect of Si on the microstructural changes during MA was discussed. The microstructures of both MA powders and extruded compacts were examined. In Al-Ti system, the solid solutionized nanocrystalline powders could be obtained by MA. On the contrary, fine Si particles were embedded as an elemental state in the matrix of Al-Ti-Si system because of the brittleness and the negligible solid solubility of Si in Al. After hot extrusion, $Al3Ti$ phase was finely precipitated in Al-10fSTi alloy, and Si particles were dissolved to form $(Al, Si)_3Ti$ phase in Al-10%Ti-2%Si alloy.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.151-152
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• 2006

Bi-Te thermoelectric powder was fabricated by mechanical alloying method for 1 to 10 hours under vacuum in planetary mill. We investigated the properties of mechanically alloyed Bi-Te powder by thermal analysis, X-ray diffractometer and FESEM with EDS Bi-Te raw material was formed to $Bi_2Te_3$ phase at condition over 3.5 hours of mechanical alloying time.

• Korean Journal of Materials Research
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• v.5 no.1
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• pp.112-122
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• 1995

Metal hydride alloys of TiFe based system have been produced by mechanical alloying(MA) method and their electrochemical characteristics have been evaluated for application for Ni/MH battery electrode. These alloys became amorphous after 36hrs ball milling and easily activated electrochemically. All MA amorphous alloys reached at the first charge/discharge cycle the maximum capacity which was 2-3 times higher than the crystalline state. But their cyclic lives were much inferior to the crystalline state. Alloying elements such as Ni, Co, Cr, Mo substituting Fe greatly improved the capacity and 180 mAh/g capacity was obtained in an alloy of TiFe_{0.6}Ni_{0.1}Co_{0.1}Cr_{0.1}Mo_{0.1}$.

• Journal of Korea Foundry Society
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• v.15 no.6
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• pp.546-557
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• 1995

This study was undertaken to obtain an improved understanding of the effects of alloying elements on the residual amounts of Mg in the melt and on the resultant microstructure of compacted vermicular graphite cast irons, and the influence of alloying elements and cooling rates during solidification on the formation of phosphide eutectics, and on the mechanical properties of compacted vermicular graphite cast irons containing copper, tin, molybdenum for producing pearlitic matrix, and also containing phosphorus and boron for increasing wear resistance were evaluated.

• Laser Solutions
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• v.2 no.1
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• pp.16-21
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• 1999

The surface of Alloy 600 was alloyed using a continuous wave $CO_2$ laser beam in order to improve its corrosion resistance. Laser surface alloying (LSA) was done by melting the surface electroplated with Cr of the alloy. The Cr concentration of the alloyed surface was 28-30 at.%, which is similar to that of Alloy 690. Alloying elements in the alloyed layer was observed to be distributed very homogeneously all over the alloyed region. According to the electrochemical and modified Huey tests, the corrosion resistance, in particular the grain boundary corrosion resistance, of the LSA specimens was significantly improved, compared with that of the as-received(AR) specimen. This improved corrosion resistance of the alloyed specimen might be attributed to the high Cr content which could make possible formation of more stable and dense passive film onto its surface.