• Proceedings of the Materials Research Society of Korea Conference
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• 1994.05a
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• pp.66-67
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• 1994

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.483-486
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• 1995

Soft magnetic properties of Fe-based (Fe,Co)-B-Al-M (M=Nb, Mo or Ta) nanocrystalline alloy have been investigated. The alloy obtained directly form the rapid solidification process. Microstructure of the alloy is a mixtu re of ultrafine bcc Fe(Co) nanocrystallines and a small amount of retained amorphous phase. Heat treatment of as-prepared alloys improves soft magnetic properties in high frequency range. ${(Fe_{.85}Co_{.15})}_{70}B_{18}Al_{10}Ta_{6}$ alloy alloy annealed at $500^{\circ}C$ for 1 h shows the most improved soth magnetic properties among the alloy examined. Average grain size of the nanocystalline is about 10 nm.

• Korean Journal of Materials Research
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• v.9 no.10
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• pp.1037-1040
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• 1999

Magnetic characteristics of some anisotropic mischmetal- FeB- (Co,Ti,Al) permanent magnets have been investigated. The magnets were fabricated by using hot-pressed and die-upsetting. Hot-pressed $\textrm{(MM)}_{12.5}\textrm{Fe}_{71.9}\textrm{Co}_{5.0}\textrm{Al}_{2.0}\textrm{B}_{8.6}$ permanent magnet showed $\textrm{H}_{c}$=4.27 kOe, $\textrm{B}_{r}$=4.75 kG, $\textrm{(BH)}_{max}$=3.82 MGOe, and die- upset magnet showed $\textrm{H}_{c}$=3.10 kOe, $\textrm{B}_{r}$=5.58 kG, $\textrm{(BH)}_{max}$=5.34 MGOe, respectively. Hot-pressed $\textrm{(MM)}_{12.5}\textrm{Fe}_{77.9}\textrm{Ti}_{1.0}\textrm{B}_{8.6}$ permanent magnet showed $\textrm{H}_{c}$=3.75 kOe, $\textrm{B}_{r}$=4.64 kG, $\textrm{(BH)}_{max}$=2.78 MGOe, and die- upset magnet showed $\textrm{H}_{c}$=3.29 kOe, $\textrm{B}_{r}$=5.01 kG, $\textrm{(BH)}_{max}$=3.54 MGOe, respectively. X-ray diffraction and transmission electron microscopy revealed that the higher energy products in the die-upset magnets results from alignment of the c-axis along the die-upsetting direction. The magnetic anisotropy in hot-pressed MM-FeB- Al magnet is increased by the substitution of Co for Fe.

• Resources Recycling
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• v.14 no.5 s.67
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• pp.24-31
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• 2005

In order to recover valuable metals from fine-grained electronic waste, bioleaching of Cu, Zn, Al, Co, Ni, Fe, Sn and Pb were carried out using Aspergillus niger as a leaching microorganism in a shaking flask. Aspergillus niger was able to grow in the presence of electronic scrap. The formation of organic acids(citric and oxalic acid) from Aspergillus niger caused the mobilization of metals from waste electronic scrap. In a preliminary study, in order to obtain the data on the leaching of Cu, Zn, Al, Fe, Co and Ni from electronic scrap, chemical leaching using organic acid(Citric acid and Oxalic acid) was accomplished. At the electronic scrap concentration of 50 g/L, Aspergillus niger were able to leach more than 95% of the available Cu, Co. But Al, Zn, Pb and Sn were leached about 15-35%. Ni and Fe were detected in the leachate less than 10%.

• Korean Journal of Materials Research
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• v.2 no.2
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• pp.143-150
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• 1992

Crystal structures and magnetic properties of annealed Co-(Al-Fe) alloys have been investigated. Annealed specimens showed superparamagnetism when x=0.05 and ferromagnetism when $x{\geq}0.10$. Magnetization increased as x increased. X-ray diffraction data revealed that specimens were single-phase in B2(CsCl) structure with constant lattice parameter $2.87{\AA}$. The experimental results were analized on the point of view of the local environmental effect of magnetic atoms.

• Applied Chemistry for Engineering
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• v.20 no.5
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• pp.522-526
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• 2009

The catalytic oxidation of 1,2-dichloribenzene (1,2-DCB) and simultaneous catalytic reduction of nitrogen oxides over the single catalyst has been investigated over various metals (Ru, Mn, Co and Fe) supported on $Al_2O_3$ and $CeO_{2}$. The activity of the different catalysts for catalytic oxidation of 1,2-dichloribenzene depended on the used metal, Ru/Co/$Al_2O_3$, Mn-Fe/CeO2 and Cr/$Al_2O_3$ (commercial catalysts) being the most actives ones. In the catalytic oxidation of chlorobenzene (CB), Ru/Co/$Al_2O_3$ is better than Pt-Pd/$Al_2O_3$, which is the well-known catalyst good for VOC oxidation. Furthermore, it has a good durability on the deactivation by $Cl_2$ and sulfur. For nitrogen oxides (NOx) removal, NOx conversion was 70% at $260^{\circ}C$.

• Journal of Magnetics
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• v.19 no.1
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• pp.55-58
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• 2014

We have synthesized ferromagnetic ${\tau}$-phase $Mn_{54}Al_{46}/{\alpha}$-phase $Fe_{65}Co_{35}$ composite by annealing a mixture of paramagnetic ${\varepsilon}$-phase $Mn_{54}Al_{46}$ and ferromagnetic ${\alpha}$-phase $Fe_{65}Co_{35}$ particles at $650^{\circ}C$. The volume fraction ($f_h$) of hard ${\tau}$-phase $Mn_{54}Al_{46}$ of the composite was varied from 0 to 1. During the annealing, magnetic phase transformation occurred from paramagnetic ${\varepsilon}$-phase to ferromagnetic ${\tau}$-phase $Mn_{54}Al_{46}$. The magnetization and coercivity of the composite monotonically decreased and increased, respectively, as the $f_h$ increased. These results are in good agreement with our proposed composition dependent coercivity and modified magnetization equations.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.708-709
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• 2006

New Al-based alloys with very high ultimate tensile strength were developed in high Al concentration range of 91-95 at.% for Al-Fe-Cr-Ti-M (M: Co and Mo) systems and Al-Fe-Cr-Mo-Ti-Co system by the dispersion of nanoscale quasicrystalline particles in Al phase. The effect of adding elements, M was discussed in the viewpoint of stability of super-cooled liquid state and formation ability of quasicrystalline phase. The P/M Al-Fe-Cr-Ti-M alloys with dispersed nanoscale quasicrystalline particles exhibited ultimate tensile strength of 350MPa at 573K and 200MPa at 673K.

• Journal of the Korean Magnetics Society
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• v.16 no.6
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• pp.276-278
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• 2006

The switching characteristics of magnetic tunnel junctions (MTJs) comprising amorphous ferromagnetic CoFeSiB free layer have been investigated. CoFeSiB was used for the free layer to enhance the switching characteristics. The typical junction structure was $Si/SiO_{2}/Ta$ 45/Ru 9.5/IrMn 10/CoFe $7/AlO_{x}/CoFeSiB\;(t)/Ru\;60\;(in\;nm)$. CoFeSiB has low saturation magnetization ($M_{s}$) of $560\;emu/cm^{3}$ and high anisotropy constant ($K_{u}$) of $2800\;erg/cm^{3}$. These properties caused low coercivity ($H_{c}$) and high sensitivity in MTJs, and it also confirmed in submicrometer-sized elements by micromagnetic simulation based on the Landau-Lisfschitz-Gilbert equation. By increasing CoFeSiB free layer thickness, the switching characteristics became worse due to increase of the demagnetization field.

• 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.