• 한국세라믹학회지
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• 제24권6호
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• pp.579-585
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• 1987

The effects of flux KCl and dopant Nb2O5 on the PTCR characteristics of BaTiO3 prepared by molten salt synthesis method have been investigated. As the amount of dopant Nb2O5 is over the solubility limit in BaTiO3, the room-temperature resistivity increases, and the PTCR effect and the grain size decrease. The variation of the amount of flux KCl slightly influences on the room-temperature resistivity, PTCR effect and grain size in Nb2O5 doped BaTiO3, but BaTiO3 ceramics prepared by the method of molten salt synthesis show larger PTCR effect than those of conventional calcining of mixed oxides.

• 전기화학회지
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• 제5권4호
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• pp.178-182
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• 2002

The electrochemical behavior of binder-free carbon anode, comprising of only artificial and natural graphite (AG and NG) particles, for intercalation and deintercalation of lithium ion $(Li^+)$ in aluminum chloride (AICI_3)-I-ethyl­3-methylimidazolium chloride (EMIC)-lithium chloride (LiCl)-thionyl chloride $(SOCI_2)$ room-temperature molten salt (RTMS) was studied. Binder-free carbon electrodes were fabricated using electrophoretic deposition (EPD) method. The binder-free carbon anodes provided a relatively flat charge and discharge potentials $(0\;to\;0.2V\;vs.\;Li/Li^+)$ and current capabilities $(250-340mAh{\cdot}g^{-1})$ for the intercalation and deintercalation of $Li^+$. Stability of the binder-free carbon anodes for intercalation and deintercalation of 50 cycles was confirmed.

• 한국전기전자재료학회논문지
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• 제27권8호
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• pp.528-534
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• 2014

Thermal batteries are primary reserve batteries that use inorganic salt as electrolytes which are inactive at room temperature. The two principal heat sources that have been used in thermal batteries are heat paper and heat pellets. As soon as the heat paper, which is ignited by the initiator, in turn ignites the heat pellets, all the solid electrolytes are melted into excellent ionic conductors. However, the high combustion temperature by heat papers in thermal batteries causes thermal decomposition at the cathode, eventually leading to a thermal runaway. In this paper, we have attempted to prepare $Zr/BaCrO_4$ heat papers coated with KCl molten salt. We have also investigated the effect of a molten salt coating on the heat papers through the thermal characteristics such as calorimetric value, combustion temperature and burning rate. The calorimetric value and combustion temperature of heat papers were reduced with an increase in the molten salt coating. As a result, the molten salt coating on heat papers greatly reduced risk of a thermal runaway and improved the stability of thermal batteries.

• 한국세라믹학회지
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• 제25권4호
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• pp.349-356
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• 1988

The PTCR characteristics of (Ba0.8Pb0.2)TiO3 ceramics prepared by the molten salt sysnthesis (MSS) method have been investigated as a function of the amount of Nb2O5 dopant and KCl flux. When the weight ratio of KCl to raw material is 0.8, the resistivity at room temperature decreases with increasing amount of Nb dopant up to 0.6 atom%. It can be explained by compensation for electrons due to Nb+5 ion and holes due to K+ ion. The resistivity of (Ba0.8Pb0.2)(Ti0.994Nb0.006)O3 ceramics at room temperature decreases with increasing the ratio of KCl to raw material up to 0.6, and then increases. These results can be explained by the effect of K+ ion.

• 분석과학
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• 제13권6호
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• pp.712-721
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• 2000

$LiF-BeF_2-ZrF_4$(63-30-7 mol%) 용융염은 상온에서 증류수 1ml당 최고 0.02g까지 용해율 99.9%로 용해되었다. 그리고 $ZrF_4$를 열가수분해시켜 제조된 $ZrO_2$ 산화물을 포함하는 $LiF-BeF_2-ZrF_4$ 용융염에서 $ZrO_2$ 산화물을 증류수로 침출시켜 회수하였다. 회수된 $ZrO_2$ 산화물의 결정모양은 손상되지 않았다.

• 전기화학회지
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• 제5권4호
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• pp.183-188
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• 2002

The structure of species formed in $NbCI_5-I-ethyl-3-methylimidazolium$ chloride (EMIC) room-temperature molten salt (RTMS) was examined with the Raman spectroscopic measurement and ab initio molecular orbital calculation. The equilibrium structures of $NbCl_5,\;NbCl_6^-,\;Nb_2CI_{10},\;Nb_2CI_{11}^-,\;Nb_3CI_6^-,\;NbCI_6^--EMI^+\;(in\;which\;NbCI_6^-$ anion approaches $EMI^+$ cation with strong interaction) and $Nb_2CI_{11}^--EMI^+$ were obtained with the HF/LANL2DZ level of calculation. The harmonic frequencies at each equilibrium structure were compared with Raman spectra. The harmonic frequencies of $NbCI_6^--EMI^+,\; Nb_2CI_{11}^--EMI^+,\;and\;Nb_2CI_{10}$ were in good agreement with the Raman spectra of RTMS melts. In the $NbCI_5-EMIC RTMS$, the main species were $NbCI_6^-\;and\;EMI^+$. In the $NbCl_5-EMIC$ RTMS added $NbCl_5\;over\;50mol\%$, small amount of $Nb_2CI_{11}^-\;and\; Nb_2CI_{10}$ were also formed. The structures of anions and cation in the RTMS distorted from free ions with Coulomb force.

• Nuclear Engineering and Technology
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• 제52권6호
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• pp.1243-1251
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• 2020

Irradiation-induced damage of binderless nanoporous-isotropic graphite (NPIG) prepared by isostatic pressing of mesophase carbon microspheres for molten salt reactor was investigated by 3.0 MeV He⁺ irradiation at room temperature and high temperature of 600 ℃, and IG-110 was used as the comparation. SEM, TEM, X-ray diffraction and Raman spectrum are used to characterize the irradiation effect and the influence of temperature on graphite radiation damage. After irradiation at room temperature, the surface morphology is rougher, the increase of defect clusters makes atom flour bend, the layer spacing increases, and the catalytic graphitization phenomenon of NPIG is observed. However, the density of defects in high temperature environment decreases and other changes are not obvious. Mechanical properties also change due to changes in defects. In addition, SEM and Raman spectra of the cross section show that cracks appear in the depth range of the maximum irradiation dose, and the defect density increases with the increase of irradiation dose.

• Bulletin of the Korean Chemical Society
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• 제30권1호
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• pp.233-235
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• 2009

• 방사성폐기물학회지
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• 제16권2호
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• pp.165-172
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• 2018

용융염-액체금속 추출공정에서 형성되는 액적 크기를 추정하는 방안으로 용융염-액체금속 계를 상온에서 유사한 물-수은 계로 대체하여 액적 형성 실험을 노즐의 종류에 따라 수행하여 Scheele-Meister 모델의 적용성을 평가하였다. 실험에서 액적의 크기 측정은 디지털카메라와 이미지분석 소프트웨어를 사용하였으며 노즐은 0.018 cm과 0.025 cm의 구멍 크기를 가지며 수은의 통과 길이가 1.3 cm인 상용 니들과 두께가 0.5 cm이며 0.0148 cm 구멍 2개, 0.0135 cm 구멍 3개, 0.0135 cm 구멍 4개인 것을 제작하여 사용하였다. 각각의 노즐에서 형성된 액적은 노즐 아래 20 cm까지 안정적인 구형을 유지하였다. 액적 크기의 측정치를 Scheele-Meister 모델의 추정치와 비교하였을 때 10% 오차 범위 안에서 일치하였다. 실험 결과는 물-수은 계에서 액적을 안정적으로 형성시키는 노즐에 대해 액적 크기 추정을 위한 Scheele-Meister 모델이 적용될 수 있음을 보였다.

• 한국세라믹학회지
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• 제25권3호
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• pp.293-299
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• 1988

The effects of flux KCl and dopants, La2O3 and Ta2O5, on the PTCR characteristics in molten salt synthesized BaTiO3 have been studied. The resistivity of BaTiO3 at room temperature decreases with increasing amount of dopant La2O3 up to 0.2 atom%, and then increases with La2O3 content. In case of dopant Ta2O5, it increases with increasing amount ofthe dopant. These results could be explained by observation of the microstructure and defect equation. From the results of complex impedance-frequency characteristics, the grain resistances are almost same but the resistances at the grain boundary are quite different.