• Journal of Korean Ophthalmic Optics Society
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• v.7 no.2
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• pp.27-31
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• 2002

Quarternary $Li_2O-B_2O_3-Al_2O_3-SiO_2$ glasses were fabricated by the function of $R({\equiv}Li_2Omole%/B_2O_3mole%)$ and $K({\equiv}(Al_2O_3mole%+SiO_2mole%/B_2O_3mole%)$. The structures of these glasses were investigated through refractive index and Vicker's hardness. The refractive index increased as the increase of the polarizability in the glass network. In the region of low $Li_2O$ content, the refractive index increased due to the increase of the polarizability in the glass network but, in the region of high $Li_2O$ content, the rate of increase of the refractive index decreased due to the increase of the molar volume caused by the formation of $BO_3{^-}$ units with relatively high molar volume. And, the refractive index decreased as the increase of $Al_2O_3+SiO_2$ content with the molar volume in the glass network. The increase and decrease of vicker's hardness values for those glasses depended on the fraction of tetrahedral $BO_4$ units and it of triangle $BO_3{^-}$ units with non-bridging oxygen, respectively.

• Journal of the Korean Ceramic Society
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• v.32 no.4
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• pp.507-515
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• 1995

The monolithic dry gels of the Li2O-Al2O3-TiO2-SiO2 system were prepared by the sol-gel technique using metal alkoxides as starting materials to obtain monolithic glass-ceramics at low temperature without melting. Activation energy for the crystal growth of the gel with 6.05% TiO2, nucleating ageng, for the preparation of Li2O-Al2O3-TiO2-SiO2 system glass-ceramic was 101.14kcal/mol. As a result of the analysis of DTA & XRD, it was confirmed that the crytallization of Li2O-Al2O3-TiO2-SiO2 system glass-ceramic was the most efficient when 6.05% TiO2, nucleating agent, was added. $\beta$-eucryptite solid solution crystals and $\beta$-spodumene solid solution crystals were detected in the sample heat treated above 85$0^{\circ}C$. The sintered gel heat treated at 85$0^{\circ}C$ had the specific surface area of 185$m^2$/g, the pore volume of 0.19cc/g and the average pore radius of 20.8$\AA$. This shows that the sintered gel is also comparatively porous material. In temperature range of 25~85$0^{\circ}C$ thermal expansion coefficient of the specimen which was crystallized for 10hrs at 85$0^{\circ}C$ was 6.7$\times$10-7/$^{\circ}C$, which indicated that the crystallized specimen was turned out to be the glass-ceramic with low thermal expansion.

• Electrical & Electronic Materials
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• v.10 no.2
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• pp.166-171
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• 1997

The photomachinable glass-ceramics of Ag and CeO$_{2}$ added to Li$_{2}$O-Al$_{2}$O$_{3}$-SiO$_{2}$-K$_{2}$O glass system was investigated as a function of UV irradiation time. The temperature of optimum nucleation and crystal growth temperature were confirmed at 525.deg. C, 630.deg. C respectively using DTA and TMA. The phases of Li$_{2}$O.SiO$_{2}$ habit were lath-like and/or dendrite type and [002] direction of Li$_{2}$O.SiO$_{2}$ / Li$_{2}$O.2SiO$_{2}$ phases were changed according to the UV irradiation time by 400 W, 362 nm UV light source. Under that condition, the optimum UV irradiation time was 5 min.

• Journal of Electrochemical Science and Technology
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• v.8 no.2
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• pp.101-106
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• 2017

$Li_2SiO_3$ was used as a coating material to improve the electrochemical performance of $Li[Ni_{0.8}Co_{0.15}Al_{0.05}]O_2$. $Li_2SiO_3$ is not only a stable oxide but also an ionic conductor and can, therefore, facilitate the movement of lithium ions at the cathode/electrolyte interface. The surface of the $Li_2SiO_3$-coated $Li[Ni_{0.8}Co_{0.15}Al_{0.05}]O_2$ was covered with island-type $Li_2SiO_3$ particles, and the coating process did not affect the structural integrity of the $Li[Ni_{0.8}Co_{0.15}Al_{0.05}]O_2$ powder. The $Li_2SiO_3$ coating improved the discharge capacity and rate capability; moreover, the $Li_2SiO_3$-coated electrodes showed reduced impedance values. The surface of the lithium-ion battery cathode is typically attacked by the HF-containing electrolyte, which forms an undesired surface layer that hinders the movement of lithium ions and electrons. However, the $Li_2SiO_3$ coating layer can prevent the undesired side reactions between the cathode surface and the electrolyte, thus enhancing the rate capability and discharge capacity. The thermal stability of $Li[Ni_{0.8}Co_{0.15}Al_{0.05}]O_2$ was also improved by the $Li_2SiO_3$ coating.

• Journal of the Korean Ceramic Society
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• v.13 no.1
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• pp.30-34
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• 1976

In general the chemical composition of glass ceramics in Li2O-Al2O3-SiO2 system is similar to the composition of $\beta$-spodumene (Li2O-Al2O3-4SiO2). With the object to manufacture the glass ceramics which can be produced in the domestic pot the composition of glass was so settled at 1.0 Li2O.0.9Al2O3.6.0SiO2 in order to reduce the contents of Li2O, to prevent the corrosion of the pot and to decrease the cost of raw materials. 0.2 mole and 0.1 mole of the mixture of TiO2 and ZrO2 as nucleants were added to the basic composition of 1.0 Li2O-0.9Al2O3-6.0SiO2. Each sample was divided into two kinds with a TiO2/ZrO2 ratio of 2 to 1 and the other with a TiO2/ZrO2 ratio fo 1 to 1. Thermal expansion coefficient, the most important property of glass ceramics, was tested. The softening point and the melting point of the samples were observed by the use of a heating microscope. The results obtained were as follows. The manufacturing of glass ceramics seems to be possible in the industrial plant using the domestic pot. 1) The composition of the glass which can be melted in the domestic pot process was near 1.0 Li2O.0.9Al2O3.6.0SiO2. 2) The temperature range of crystal creation and crystal growth was between 850-94$0^{\circ}C$, and 5 hours holding the samples at the temperature range was enough to crystallize them. The major crystal was $\beta$-spdumene and there existed petalite partialy. 3) The thermal expansion coefficient fo the crystallized glass was negative. 4) The deforming point of the crystallized glass was 1435$^{\circ}C$.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.15 no.1
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• pp.83-90
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• 2017

The pyroprocessing of spent nuclear fuel generates LiCl-KCl eutectic waste salt containing radioactive rare earth nuclides. It is necessary to develop a simple process for the treatment of LiCl-KCl eutectic waste in a hot-cell facility. In this study, capture and solidification of a rare earth nuclide (Nd) in LiCl-KCl eutectic salt using an inorganic composite with a $Li_2O-Al_2O_3-SiO_2-B_2O_3$ system was conducted to simplify the existing separation and solidification process of rare earth nuclides in LiCl-KCl eutectic waste salt from the pyroprocessing of spent nuclear fuel. More than 98wt% of Nd in LiCl-KCl eutectic salt was captured when the mass ratio of the composite was 0.67 over $NdCl_3$ in the eutectic salt. The content of $Nd_2O_3$ in the Nd captured-composite reached about 50wt%, and this composite was directly fabricated into a homogeneous and chemical resistant glass waste in a monolithic form. These results will be utilized in designing a process to simplify the existing separation and solidification process.

• Proceedings of the Materials Research Society of Korea Conference
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• 1994.05a
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• pp.81-81
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• 1994

• The Journal of Natural Sciences
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• v.8 no.2
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• pp.111-118
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• 1996

In order to improve the chemical durability of glass in the $Na_2O$-CaO-$SiO_2$ system, it was investigated in the effect of $B_2O_3$ and ZnO addition and changing amount of each composition, $Na_2O$, $Al_2O_3$, $Li_2O$. In this minimize the change of softening point of glass was as follow.(wt%)$B_2O_3$:3.36%, ZnO:2.88%, $Na_2O$:9.93%, $Al_2O_3$, $Li_2O$:0.19%, $SiO_2$:70.56%, CaO:11.22%, $K_2O$:0.14%

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.2
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• pp.275-285
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• 1996

The effect of heat-treatment on catalytic crystallization in $LI_2O-Al_2O_3-SiO_2$ glass system over its glass transition temperature was investigated. Glass composition $4Li_2O{cdot}22AL_2O_3{cdot}66SiO_2{cdot}2TiO_2{cdot}2.5ZrO_2{cdot}1.5P_2O_5{cdot}1.0Na_2O{cdot}1.0As_2O_3$ (wt%) was selected and heat-treated at different heating conditions to obtain transparent glass-ceramic. Nucleation and crystallization behaviour of this composition were estimated by differential thermal analysis (DTA) and X-ray diffractometer (XRD) and its thermal expansion coefficients were measured by Dilatometer. As a result, glass transition temperature was $730^{\circ}C$ and two maximum nucleation temperatures were estimated at $730^{\circ}C$ and 82$0^{\circ}C$ using JMA(Johson-Mehl-Avrami) equation by DTA. $ZrTiO_4$ $\beta$-Quartz solid solution and $\beta$-Spodumene crystals were identified by XRD. The optimum crystallization temperature was 92$0^{\circ}C$ and three step heating schedule was expected to be useful to obtain transparent glass-ceramic.

• Journal of the Korean Ceramic Society
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• v.29 no.2
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• pp.127-135
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• 1992

It has been reported that natural petalite showed a low negative thermal coefficient and wide coefficient and wide coexisting region with liquid phase in Li2O-Al2O3-SiO2 system. Therefore, we investigated variation of microstructure and thermal and mechanical properties when the amount of SiO2 content in petalite compound and MgO addition to it compound were changed. As SiO2 content exceeded 80 wt%, crystal phases of $\beta$-cristobalite and $\beta$-spondumene solid solution were formed. Generally, the densification and bending strength were increased by the addition of MgO, but the positive thermal coefficient was found in the case of MgO 10 wt% addition because of second phase and glassy phase.