• Journal of Magnetics
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• v.15 no.4
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• pp.165-168
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• 2010

$Li_{0.1}Zn_{0.9}O$ and $MgFe_2O_4$ powders were synthesized using chemical methods and mixed in different proportions to prepare a mixture of $Li_{0.1}Zn_{0.9}O$ and $MgFe_2O_4$ that was thermally treated between 900 to $1100^{\circ}C$ for 1 hour. Structural characterization was done using X-ray powder diffraction measurements. Grain sizes and morphologies of $Li_{0.1}Zn_{0.9}O$, $MgFe_2O_4$, and $Li_{0.1}Zn_{0.9}O+MgFe_2O_4$ samples were observed using a scanning electron microscope. Variation of magnetic properties of the $Li_{0.1}Zn_{0.9}O+MgFe_2O_4$ samples due to the addition of $Li_{0.1}Zn_{0.9}O$ was studied in relation to the structural changes occurring due to the thermal treatment. In particular, changes in the cationic distribution between the tetrahedral and octahedral positions were studied with respect to the increase of the annealing temperature. Magnetization was found to be dependent on the cations distributed in the tetrahedral and octahedral sites of the $MgFe_2O_4$.

• Korean Journal of Materials Research
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• v.10 no.7
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• pp.471-477
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• 2000

Corrosion behavior of Fe-Ni-Cr alloy in molten salts of LiCl and LiCl-$Li_2O was investigated in the tempera-ture range of $650~850^{\circ}C$. In the molten salt of LiCl, and internal oxidation of Fe occurred in the KSA(Kaeri Superalloy)-1 alloy without containing Cr, while a dense protective oxide scale of $LiCrO_2$ was formed in the KSA-4, Incoloy 800H and KSA-5 alloys. In the mixed molten salt of LiCl-$Li_2O$, internal oxidation of Fe and Cr took place in the KSA-1 and KSA-4 alloys, respectively. Non-protective porous oxide scales consisting of $LiCrO_2$ and Ni were formed in the Incoloy 800H and KSA-5. The corrosion rate of the alloys increased with the increase in Cr content and the corrosion rate followed the parabolic law for the alloy containing Cr content less than 8%, and the linear law for the alloy containing Cr content more than 8%. Such a corrosion behavior of the alloy in the mixed molten salt of LiCl-$Li_2O$ was interpreted in terms of the basic fluxing mechanism of protective oxide scale of $Cr_2O_3$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.241-242
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• 2006

In this work, the $LiFePO_4-LiCoO_2$ mixed cathode electrodes were prepared and their electrochemical performances were measured in different current density. The cell of $LiFePO_4-LiCoO_2$ observed two voltage plateau regions at 3.4 and 3.9V. The cell of $LiFePO_4-LiCoO_2$ (90:10 wt%) mixed cathode delivered a discharge capacity of ca. 139.8 mAh/g at a 0.2C rate. The capacity of the cell decreased with the current rate and a useful capacity of ca 85.7mAh/g was obtained at a 2C rate.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.06a
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• pp.139-143
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• 1997

The doping effects of Mg and/or Fe ions on congruent LiNbO$_3$ single crystal growth were studied in order to clarify the roles of MgO in Fe doped LiNbO$_3$ single crystals. The effective distribution coefficienct of Fe was found decreased drastically from 0.85 to 0.5 by the addition of MgO into the LiNbO$_3$ melt. M ssbauer spectra revealed that the addition of MgO reduces the occurrence of Fe2+ ions during growth in air. Therefore, it is likely that there would be two important roles of MgO in Fe doped LiNbO$_3$. One is to suppress the incorporation of all Fe ions, and the other is to reduce the concentration of Fe2+ ions among the total Fe ions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05b
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• pp.5-9
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• 2005

$LiFePO_4$ is a potential candidate for the cathode material of the lithium polymer batteries. $LiFePO_4$ cathode active materials were synthesized by coating on the $LiFePO_4$ was tried using $TiO_2$ and corbon in oreder to increase cyclic performance and electronic conductivity. Highly dispersed on the particles enhances the electronic conductivity and increases the capacity. For lithium polymer battery applications, $LiFePO_4$/SPE/Li and $LiFePO_4$-$TiO_2$/SPE/Li 'cells were characterized electrochemically by cyclic volatammetry and charge/discharge cycling. The $LiFePO_4$-carbon-$TiO_2$ cathode in PVDF-PC-EC-$LiCIO_4$ electrolyte showed high capacity at high current density.

• Korean Journal of Materials Research
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• v.14 no.11
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• pp.813-820
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• 2004

The electrolytic reduction of spent oxide fuel involves the liberation of oxygen in a molten LiCl electrolyte, which is a chemically aggressive environment that is very corrosive for typical structural materials. So, it is essential to choose the optimum material for the process equipment handling molten salt. In this study, corrosion behavior of Haynes 263, 75, and Inconel X-750, 718 in molten salt of $LiCl-Li_{2}O$ under oxidation atmosphere was investigated at $650^{\circ}C\;for\;72\sim360$ hours. At $3\;wt\%\;of\;Li_{2}O$, Haynes 263 alloy showed the highest corrosion resistance among the examined alloys, and up to $8\;wt\%\;of\;Li_{2}O$, Haynes 75 exhibited the highest corrosion resistance. Corrosion products were formed $Li(Ni,Co)O_2,\;LiNiO_2\;and\;LiTiO_2\;and\;Cr_{2}O_3$ on Haynes 263, $Cr_{2}O_3,\;NiFe_{2}O_4,\;LiNiO_2,\;Li_{2}NiFe_{2}O_4,\;Li_{2}Ni_{8}O_10$ and Ni on Haynes 75, $Cr_{2}O_3,\;(Al,Nb,Ti)O_2,\;NiFe_{2}O_4,\;and\;Li_{2}NiFe_{2}O_4$ on Inconel X-750 and $Cr_{2}O_3,\;NiFe_{2}O_4\;and\;CrNbO_4$ on Inconel 718, respectively. Haynes 263 showed local corrosion behavior and Haynes 75, Inconel X-750, 718 showed uniform corrosion behavior.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.5
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• pp.447-453
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• 1999

Congruent $LiNbO_3$ crystals with doped Mg and codoped with Mn or Fe were grown by the Czochralski method. It is known that the physical properties of $LiNbO_3$ depend strongly on the addition of Mg and transition metals. This is established by studying the following properties; XRD patterns, the phase transition temperature, energy of the fundamental absorption edge, the shape of the absorption band of the $OH^-$ vibration and lines of the ESR of $Fe^{3+},\; Mn^{2+}$. The position of the UV absorption edge and the shape and peak point of the absorption band of the $OH^-$ vibrational band changed monotonously up to a critical concentration of $Mg^{2+}$ ions. The mechanism of the incorporation of Mg ions changes at this concentration. The transition temperature was estimated by measuring the dielectric temperature behavior up to $1230^{\circ}C$ in a frequency range of 100Hz to 10MHz. EPR of $Mn^{2+}\;and\; Fe^{3+}$ ions were employed to investigated the Mg doping effects in the $LiNbO_3$ crystal. The increase of linewidths and the asymmetry of signals were observed in all crystals. New signals of $Fe^{3+}$ arising from the new centers were observed I the heavily Mg-doped crystals.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.4
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• pp.525-531
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• 1998

A series of $LiNbO_3$ single crystals were grown by the Czochralski method from a congruent melt, a congruent melt with 0.05 mol% $Fe_2O_3$, a congruent melt with 6 wt.% $K_2O$ and a congruent melt with 6 wt.% $K_2O$ and 0.05 mol% $Fe_2O_3$ respectively. The growth of $LiNbO_3$ crystal from a congruent melt 6 wt.% $K_2O$ leads to nearly stoichiometric specimens. This is established by studying the following properties; XRD patterns, temperature dependences of the phase transition temperature, energy of the fundamental absorption edge, the shape of the absorption band of the $OH^-$vibration and linewidths of the ESR of $Fe_{Li}^{3+}$.

• Journal of Powder Materials
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• v.21 no.3
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• pp.185-190
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• 2014

$FeS_2$ has been widely used for cathode materials in thermal battery because of its high stability and current capability at high operation temperature. Salts such as a LiCl-KCl were added as a binder for improving electrical performance and formability of $FeS_2$ cathode powder. In this study, the effects of the addition of $Li_2O$ in LiCl-KCl binder on the formability of $FeS_2$ powder compact were investigated. With the increasing amount of $Li_2O$ addition to LiCl-KCl binder salts, the strength of the pressed compacts increased considerably when the powder mixture were pre-heat-treated above $350^{\circ}C$. The heat-treatment resulted in promoting the coating coverage of $FeS_2$ particles by the salts as $Li_2O$ was added. The observed coating as $Li_2O$ addition might be attributed to the enhanced wettability of the salt rather than its reduced melting temperature. The high strength of compacts by the $Li_2O$ addition and pre-heat-treatment could improve the formability of $FeS_2$ raw materials.

• 한국전기화학회:학술대회논문집
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• 2003.10a
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• pp.21-21
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• 2003