• Journal of the Korean Ceramic Society
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• v.24 no.2
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• pp.179-185
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• 1987

The microstructure and the electrical conductivity of MgO-doped Cr2O3 were investigated as a function of oxygen partial presure, temperature, and MgO content. The grain size was estimated about 1.0$\mu\textrm{m}$. The solubility limit is increased with oxygen partial pressure. Above the solubility limit of MgO in Cr2O3, the spinel phase(MgCr2O4) is formed by the reaction of MgO and Cr2O3. The electrical conductivity of MgO-doped Cr2O3 within the solubility limit is increased with MgO content. Above the solubility limit, however, it is decreased with increasing MgO content because of the formation of the spinel phase.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.108-108
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• 2009

ITO에 사용되는 주된 재료인 인듐의 bixbyite 구조는 TCOs의 전기적 특성에서 매우 중요한 것으로 알려져 있다. 때문에 인듐의 Bixbyite구조를 유지하면서 인듐의 사용량을 줄이기 위해 최적의 Solubility limit에 관해 연구하였다. 이를 위해 In2O3-ZnO-SnO2의 삼성분계 기본 조성에 두가지 물질을 추가로 첨가하여 첨가량에 따른 Solubility limit을 연구하였다. Solubility limit의 측정을 위해 X-ray Diffractometer(XRD)를 사용하였으며, 첨가 원소의 양이 증가할수록 TCOs target의 Latice parameter값은 작아졌다, SEM을 통한 미세구조의 관찰로 원소첨가에 따른 샘플의 소결에너지 변화를 분석할 수 있었다. 제작된 시편의 정성분석 및 Chemical binding Energy를 측정하기 위해 X-ray Photo Spectroscopy (XPS)를 이용하였으며, 전기적인 특성 측정을위해 4-Point prove mesurement 방법을 사용하였다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.9
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• pp.960-966
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• 2004

On the bases of the results from "Additive Coating of BaTiO$_3$ Powder using Sol Coating Method I", experimental condition was defined. Representative additives for BaTiO$_3$, that is to say, Mg, Ca and Mn were experimented. The sources of the metal ion were used by organometal complex. As added it, the stability of BaTiO$_3$ sol was evaluated. Mg and Ca were stable, however, The solubility limit of Mn-ATH was 0.05 mol ratio in Mn-ATH/sol. The solubility limit of Mg ion in BaTiO$_3$ was lower than 2 mol%. From the x Ray diffraction patterns, lattice parameters were different with temperature and additives, because the solubility of metal ion was varied in BaTiO$_3$. The dielectric constant of BaTiO$_3$ powders which coated with the 1.5 mol% Mg and calcined at 1200$^{\circ}C$ was increased with 20%.

• Journal of the Korean Ceramic Society
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• v.34 no.8
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• pp.834-842
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• 1997

Controlled Ca impurity implanted inner crack-like pore in the high purity alumina single crystal, sapphire, had been created by micro-fabrication technique, which includes ion implantation, photo-lithography, Ar ion milling, and hot press technique. The morphological change and the healing of cracklike pore in Ca doped high purity single crystal alumina, sapphire, during high temperature heat treatment in vacuum were observed using optical microscopy. The dot-like surface roughening was developed and hexagon like crystal appeared on inner surface of crack-like pore after heat treatment. Bar type crystals, probably CaO.6Al2O3, were observed on the inner surface after 1 hour heat treatment at 1, 50$0^{\circ}C$, but this bar type crystal disappeared after 1 hour heat treatment at 1, $600^{\circ}C$. This disappearance means that there should be a little increase of Ca solubility limit to alumina at this temperatures.

• Journal of the Korean Ceramic Society
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• v.37 no.8
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• pp.787-791
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• 2000

Samples with the nominal composition, Bi2-xGexSr2CaCu2O8＋$\delta$ (x=0, 0.1, 0.2, 0.3, 0.4, 0.5) were prepared by the solid-state reaction method. We have studied the effect of substitution Ge for Bi and investigated the superconducting properties by changing oxygen content with Ge substitution. It was found that temperature difference, ΔK, between TCon and TCzero was considerably smaller in the samples prepared by the intermediate pressing method than that in the samples by the solid-state reaction method. We found the solubility limit of Ge to the 80 K single phase was around x=0.3. Within the solubility limit, lattice constant c decreased with the increase of x. In the region of the 80K single phase, the onset critical temperature TCon increased and excess oxygen content decreased with increase of x.

• Nuclear Engineering and Technology
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• v.42 no.5
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• pp.552-561
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• 2010

This study investigates the solubility of neptunium (Np) in the deep natural groundwater of the Korea Atomic Energy Research Institute Underground Research Tunnel (KURT). According to a Pourbaix diagram (pH-$E_h$ diagram) that was calculated using the geochemical modeling program PHREEQC 2.0, the redox potential and the carbonate ion concentration both control the solubility of neptunium. The carbonate effect becomes pronounced when the total carbonate concentration is higher than $1.5\;{\times}\;10^{-2}$ M at $E_h$ = -200 mV and the pH value is 10. Given the assumption that the solubility-limiting stable solid phase is $Np(OH)_4(am)$ under the reducing condition relevant to KURT, the soluble neptunium concentrations were in the range of $1\;{\times}\;10^{-9}$ M to $3\;{\times}\;10^{-9}$ M under natural groundwater conditions. However, the solubility of neptunium, which was calculated with the formation constants of neptunium complexes selected in an OECD-NEA TDB review, strongly deviates from the value measured in natural groundwater. Thus, it is highly recommended that a prediction of neptunium solubility is based on the formation constants of ternary Np(IV) hydroxo-carbonato complexes, even though the presence of those complexes is deficient in terms of the characterization of neptunium species. Based on a comparison of the measurements and calculations of geochemical modeling, the formation constants for the "upper limit" of the Np(IV) hydroxo-carbonato complexes, namely $Np(OH)_y(CO_3)_z^{4-y-2z}$, were appraised as follows: log $K^{\circ}_{122}\;=\;-3.0{\pm}0.5$ for $Np(OH)_2(CO_3)_2^{2-}$, log $K^{\circ}_{131}\;=\;-5.0{\pm}0.5$ for $Np(OH)_3(CO_3)^-$, and log $K^{\circ}_{141}\;=\;-6.0{\pm}0.5$ for $Np(OH)_4(CO_3)^{2-}$.

• Journal of the Korean Ceramic Society
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• v.33 no.8
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• pp.877-882
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• 1996

• Proceedings of the Korean Ceranic Society Conference
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• 2002.10a
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• pp.168.2-168
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• 2002

• Journal of the Korean Society for Heat Treatment
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• v.14 no.1
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• pp.17-21
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• 2001

The effects of Cr content above its solubility limit and thermomechanical treatment on tensile strength and electrical conductivity of Cu-Cr alloys were studied to obtain optimum Cr content exhibiting a high tensile strength without degradation of electrical conductivity. The increase in Cr content above the solubility limit increased tensile strength of Cu-Cr alloys without deterioration of the electrical conductivity. The electrical conductivity was not affected by cold rolling. The electrical conductivity of a Cu-3.5%Cr alloy subjected to cold rolling ${\rightarrow}$ aging treatment ($450^{\circ}C{\times}1hr$) ${\rightarrow}$ cold rolling was equal to that of the alloy subjected to cold rolling ${\rightarrow}$ aging treatment. However, the tensile strength of the alloy subjected to the former thermomechanical treatment was superior to that of the alloy subjected to the latter thermomechanical treatment at all the deformation degrees.

• Journal of the Korean Ceramic Society
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• v.40 no.5
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• pp.405-409
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• 2003

The effect of substitution of Gd ions for Ca ions in the B $i_{1.84}$P $b_{0.34}$S $r_{1.91}$(C $a_{1-x}$ G $d_{x}$)$_{2.03}$ C $u_{3.06}$ $O_{ 10+{\delta}}$/ (x=0.0~0.06) was investigated by measuring x-ray diffraction patterns, lattice constants, do resistivity and Hall effect. We found the solubility limit of Gd in the 110 K phase to be x < 0.015. Within the solubility limit, the c-axis seemed to decrease with increasing x. In the region of the 110 K single phase, the critical temperature $T_{c}$ gradually decreased with an increasing the Gd concentration x, corresponding to a small change of the carrier concentration.