• 연구논문집
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• s.29
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• pp.141-149
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• 1999

Brazing of Fe-Cr-Al alloy was carried out at $1200^{\circ}C$ in vacuum furnace using nickel-based filler metals : BNi-5 powder(Ni-Cr-Si-Fe base alloy} and MBF-50 foil (Ni-Cr-Si-B). The effect of boron content on the stability of oxide scale on the brazed joint was investigated by means of cyclic oxidation test performed at $1050^{\circ}C$ and $1200^{\circ}C$. Apparently, the joints brazed with MBF-50 containing boron showed relatively stable oxidation rates compared to boron-free BNi-5 at both temperatures. However, it was considered that the slower weight loss of MBF-50 brazed specimen wasn’t resulted from the low oxidation rate but from the spallation of oxide layer. The oxide layer consisted of thick spinel oxide on the surface and $Al_2 O_3$ internal oxide layer along the interface between mother alloy and braze, the mother alloy was also eroded seriously by the formation of spinel oxides such as $FeCr_2 O_4$ and $NiCr_2 O_4$ on the surface, likely to be induced by the change of oxide forming mechanism due to diffusion of boron from the braze. On the contrary, the joint brazed with BNi-5 showed the good oxidation resistance during the cyclic oxidation test. It seems that the oxidation can be retarded by the formation of stable $Al_2 O_3$ layer at the surface.

• Korean Journal of Materials Research
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• v.13 no.12
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• pp.791-795
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• 2003

The oxidation behaviour of Fe-XAl-0.1Y(X= 5, 10, 14 wt.%) alloys were investigated at 1073, 1173 and 1273 K in oxygen/ nitrogen gas atmosphere for 1∼24 hrs using SEM/EDX, XRD and EPMA. The weight changes of Fe-XAl-0.1Y alloys followed the parabolic rate law. Oxidation rates of 10Al and 14Al alloys were ten times lower than that of 5Al alloys. This is attributed to the formations of protective $A1_2$$O_3$oxides on the surface of 10Al and 14Al alloys. The oxidation product scales of the 5Al alloy showed that thick iron oxide scales($Fe_2$$O_3$, $Fe_3$$O_4$) containing porosities formed during early stages of oxidation. With continued oxidation, aluminum oxide was formed at the alloy/scale interface.

• Korean Journal of Materials Research
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• v.20 no.1
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• pp.37-41
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• 2010

Creep tests were conducted under a condition of constant stress on two aluminum-based alloys containing particles: Al-5% Mg-0.25% Fe and Al-5% Zn-0.22% Fe. The role of grain boundary sliding was examined in the plane of the surface using a square grid printed on the surface by carbon deposition and perpendicular to the surface using two-beam interferometry. Estimates of the contribution of grain boundary sliding to the total strain, $\varepsilon_{gbs}/\varepsilon_t$ reveal two trends; (i) the sliding contribution is consistently higher in the Al-Mg-Fe alloy, and (ii) the sliding contribution is essentially independent of strain in the Al-Mg-Fe alloy, but it shows a significant decrease with increasing strain in the Al-Zn-Fe alloy. Sliding is inhibited by the presence of particles and its contributions to the total strain are low. This inhibition is attributed to the interaction between the grain boundary dislocations responsible for sliding and particles in the boundaries.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.1
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• pp.1-10
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• 2011

To investigate the combination dyeing properties of natural dyes, the combination dyeing using gallnut,-Al, Cu, Fe-sappan wood, and gallnut-Al, Cu, Fe-gardenia was performed on bast fiber of mulberry, cotton, silk, and their K/S values, colors, and sunlight fastness were measured. The gallnut-Al, Cu, Fe-gardenia dyeing showed the highest K/S values when the dyeing concentration of gallnut is 3%. It tended to show the higher K/S values than gallnut-Al, Cu, Fe-sappan wood. The silk showed the highest values of in K/S, and then followed by cotton, and bast fiber of mulberry. The mordants developed different colors on the bast fiber and the cotton treated with gallnut-Al, Cu, Fe-sappan wood. However, the silk showed a series of YR, showing no effect of the mordants on the development of color. The combination dyeing of gallnut-Al, Cu, Fe-gardenia showed a series of Y. The results showed that sappan wood could develop various colors but gardenia could develop a series of Y. No distinct improvement on sunlight fastness of the combination dyeing was observed.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.1
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• pp.1-8
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• 2017

Fe-9.8Si-6.0Al mother alloy was manufactured using by Fe-3.5Si recycled scrap and Si powder. And then, soft magnetic alloy powder of $D_{50}$ size and sphere type were prepared by gas atomization process. To obtain the soft magnetic powder of a high aspect ratio, in the first, we conducted the ball milling process for 8 hours. And heat treatment was performed under $650^{\circ}C$, 2 hours and $N_2$ atmosphere condition for reducing the residual stress of the powder. Based on these process, we made around $50{\mu}m$ diameter Fe-9.8Si-6.0Al powder, which morphology and shape was a similar to the commercial Fe-Si-Al powder. Finally, the soft magnetic sheets were prepared by tape casting process using by those powders. The permeability of the tape casting sheet was measured, and we confirmed the possibility of reusing to the soft magnetic materials of Fe-Si electric sheet scrap.

• Journal of the Mineralogical Society of Korea
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• v.2 no.1
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• pp.8-10
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• 1989

Sphene from the McDonald pegmatite near Bancroft, Ontario, Canada was analyzed using EPMA. It contains 4.3 to 6.3 weight percent of Nb2O5 with an average formula Ca1.02(Ti0.62Al0.22Nb0.07Fe0.06Ta0.01)Si0.99(O4.85F0.16). Three types of subtitutions are possible; 1)2Ti4+=(Nb, Ta)5+ + (Al, Fe3+), 2) Ti + O = (Al, Fe3+) + (F, OH), and 3) 2Ti + O = Fe2+ + (Nb, Ta)5+ + (F, OH). T재 different schemes of substitutions for balancing the analysis are considered when the iron is either all ferric or all ferrous. Assuming stoichiometry fo Ca and Si, a general formula derived from the two different schemes is Ca(Ti0.64Al0.22Fe3+0.06-X {{{{Fe_{x}^{2+} }} Nb0.01)Sio4.80-XF0.16(OH)0.04+x.

• Journal of Korea Foundry Society
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• v.26 no.3
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• pp.123-128
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• 2006

Mechanical and thermal properties of spray-cast hypereutectic Al-20wt.%Si-xwt.%Fe alloys (x=0, 1, 3, 5) were investigated. After the spray-casting, hot extrusion was performed at $400^{\circ}C$. Intermetallic compound (${\beta}-Al_5FeSi$) and primary Si are observed in the spray-cast aluminum alloys. The size of primary Si and intermetallic compound of the spray-aluminum alloys became finer and more uniformly distributed than that of the permanent mold cast ones. Ultimate tensile strength of the spray-cast aluminum alloys increased by increasing Fe contents, but that of the permanent mold cast aluminum alloys decreased by increasing Fe contents possibly due to increased amount of coarse intermatallic compound. The coefficient of thermal expansion (CTEs) of the aluminum alloys became lower with finer primary Si and intermetallic compound, and this is attributed to the increased amount of interfacial area between the aluminum matrix and the phases of finer Si and intermetallic compound.

• Journal of the Korean Vacuum Society
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• v.16 no.5
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• pp.377-382
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• 2007

In this study, we report the synthesis of the single-walled carbon nanotubes(SWCNTs) using laminated catalyst(Al/Fe/Al) layer deposited by sputter on Si(001). SWCNTs are grown by thermal chemical vapor deposition (TCVD) method. As the results of scanning electron microscopy(SEM), high resolution transmission electron microscopy(HR-TEM) and Raman spectroscopy, we confirmed the SWCNTs bundles with narrow diameter distribution of $1.14{\sim}1.32\;nm$ and average G&D ratio of 22.76. Compare to the sample having Fe/Al catalyst layer, it can be proposed that the top-aluminum incorporated with iron catalyst plays an important role in growing process of CNTs as a agglomeration barrier of the Fe catalyst. Thus, we suggest that a proper quantity of aluminium metal incorporated in Fe catalyst induce small and uniform iron catalysts causing SWCNTs with narrow diameter distribution.

• Korean Journal of Metals and Materials
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• v.49 no.3
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• pp.231-236
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• 2011

Nanopowder of $Fe_2O_3$, Al, Cr and Si was fabricated by high energy ball milling. A dense nanostuctured $A_2O_3$ and $6.06Fe_{0.33}Cr_{0.16}Al_{0.23}Si_{0.29}$ composite was simultaneously synthesized and consolidated using high frequency induction heated sintering method within 1 minute from mechanically activated powders of $Fe_2O_3$, Al, Cr and Si. The grain sizes of $Al_2O_3$ and $Fe_{0.33}Cr_{0.16}Al_{0.23}Si_{0.29}$ in composite are 80 and 18 nm, respectively.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1000-1001
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• 2006

Two atomized alloy powders were pre-compacted by cold and subsequently hot forged at temperatures ranging from 653K to 845K. The addition of Cu and Mg causes a decrease in the eutectic reaction temperature of Al-10Si-5Fe-1Zr alloy from 841K to 786K and results in a decrease of flow stress at the given forging temperature. TEM observation revealed that in addition to Al-Fe based intermetallics, $Al_2Cu$ and $Al_2CuMg$ intermetallics appeared. The volume fraction of intermetallic dispersoids increased by the addition of Cu and Mg. Compressive strength of the present alloys was closely related to the volume fraction of intermetallic dispersoids.