• Journal of Ceramic Processing Research
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• v.13 no.spc1
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• pp.37-41
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• 2012

A lithium ion conducting borosilicate glass was fabricated by a conventional melt quenching technique from a mixture of Li2CO3, B2O3 and SiO2 powders. The Li ion conductivity of the lithium borosilicate glasses was evaluated in terms of the SiO2/B2O3 ratio. In the Li2O-B2O3-SiO2 ternary glass, the glass forming region decreases with an increasing Li2O content. At the same Li2O, the crystallization tendency of the glass samples increases with the SiO2/B2O3 ratio, resulting in a reduced glass forming region in the Li2O-B2O3-SiO2 ternary glass. The electrical conductivity moderately depends on the SiO2/B2O3 ratio in the Li2O-B2O3-SiO2 ternary glass. The conductivity of the glasses slightly increases with the SiO2/B2O3 ratio. The observed phenomenon can be explained by the modification of the glass structure as a function of the SiO2 content.

• 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 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 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.

• 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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.39-43
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• 1997

Effects of B$_2$O$_3$ addition in the Li$_2$O-MgO-MgF$_2$-SiO$_2$g1ass system were investigated in order to make glass-ceramics for low temperature firing substrate. Base glass was made by melting at 145$0^{\circ}C$ . This glass was analyzed by THA and DTA to settle nucleation and crystallization temperature. After crystallization. crystal phase and microstructure were absorvated by XRD and SEM. Glass powders were made by water swelling method. Average particle size was 5.44${\mu}{\textrm}{m}$

• Journal of the Korean Ceramic Society
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• v.26 no.3
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• pp.315-322
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• 1989

Li2O-Al2O3-SiO2 system glasses contained P2O5, TiO2 and ZrO2as the nucleating agents were melted and formed. The glass was subsequently heated first to nucleate and then to grow the crystals. At constant nucleating agent content the base glass compositions were varied and the influences of these variations on the crystallization behaviour were investigated. The study was made by measurement of thermal expansion coefficient, differential thermal analysis, X-ray diffraction analysis, scanning electron microscope observation and transmission measurement of crystallized glass specimen in visible region. It was shown that the content of crystalline phase decreased with increasing SiO2 content as well as decresing Li2O in the base glass compositions. As the result of X-ray diffrection analysis, the major crystal was $\beta$-quartz solid solution. The degree of crystallinity which was calculated using the noncrystalline scattering methods increased in S-shape with increasing heat treatment time. This change was similar to that in thermal expansion coefficient. The transmissions of 5mm thick samples were 80-90% in visible ray region.

• Journal of the Korean Ceramic Society
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• v.18 no.3
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• pp.163-170
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• 1981

The crystallization of $Li_2O-SiO_2$ system glasses and the effect of phase separtion to crystal nucleation were studied. The crystallization temperatures of various glasses were determined by DTA and glasses were nucleation heat treated at the temperatures ranging from 45$0^{\circ}C$ to 5$25^{\circ}C$. These glasses were thengown at $700^{\circ}C$ to observable size in the optical microscope. Crystal nucleation rates of various glasses were obtained by estimating the number of crystals per unit volume. The main crystal phase of these glasses identified by X-ray diffraction was lithium disilicate ($Li_2O$.$2SiO_2$). It was found that the crystal nucleation rate of glass (19.5% $Li_2P$-80.5% $SiO_2$), the nearest composition to lithium disilicate, was higher than other glasses. The opalescence caused by phase separation was observed in the nucleation heat treated glass (16.3% $Li_2O$-83.7% $SiO_2$). The result from nucleation density measurement of this glass indicated that the nucleation was enhanced during early stage of phase separation. The molphologies of crystals in glasses and crystal growth rate at $600^{\circ}C$ were also discussed.

• Journal of the Microelectronics and Packaging Society
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• v.3 no.2
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• pp.27-38
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• 1996

Lithium fluorhectorite 결정상을 함유한 glass ceramics 분말의 형성과 제조된 glass ceramics 분말을 이용한 저온 소결기판의 특성평가를 하였다. Li2O-MgO-MgF2-SiO2 계 유 리로 핵형성 및 결정 성장을 실시하여 lithium fluorhectorite 결정상을 지닌 glass ceramics 를 제조하였다. 유리시편의 핵형성 온도는 46$0^{\circ}C$였고 결정성장온도는 600, 640, 110$0^{\circ}C$에서 나타났다. $600^{\circ}C$에서의 결정상으 Li2.4LiSi4O10F2가 나타났다. Li2.4Mg8LiSi4와 Li2.8Mg0.6SiO4은 lithium fluorhectorite 결정상으로 되기 위한 중간상임을 확인할수 있었다. 64$0^{\circ}C$에서 열처리 후 110$0^{\circ}C$에서 재열처리하여 형성된 결정은 lithium fluorhectorite 와 tridymite가 최종 결정 상으로 나타났다. 이것은 수중에서 water swelling 현상에 의하여 분말화할 수 있었다, 기판 제조용 slurry를 제조하기 위해 glass ceramics 분말에 Al2O3분말을 0,25,50wt%로 혼합한것 과 glass ceramics 분말에 potashborosilica-te glass 분말을 15, 30, 45, 60 wt% 로 배합하 여 doctor blade 법으로 green sheet를 제조하였다. green sheet 는 950~150$0^{\circ}C$로소성하여 기판의 특성을 평가하였다. 겉보기 기공율은 3.06~19,14%이었고, 전기적 특성으로 유전상수 는 3~5(100KHz)를 나타내었다.

• Journal of the Korean Ceramic Society
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• v.18 no.3
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• pp.187-191
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• 1981

The effect of additions, $TiO_2$ and $ZrO_2$ as nucleant on the base glass which composition was determined to 0.97 $Li_2O-Al_2O_3-SiO_2$ has been investigated by means of D.T.A., X-ray diffraction and dilatation. $TiO_2$ and $ZrO_2$ as nucleant were added 0.06mole, in which ratios of $TiO_2$/$ZrO_2$ were varied 1/0, 2/1, 1/1, 1/2 and 0/1. The crystalline phases were appeared to $\beta$-spodumene as principal, $\beta$-eucryptite and $ZrO_2$ as secondary, regardless of nucleant variations. The crystallinity of the crystallized glass added $TiO_2$, $ZrO_2$ mixture as nucleant was higher than that of the glass added $TiO_2$ or $ZrO_2$ only. The crystallinity of the glass added $TiO_2$/$ZrO_2$ =1/1 was highest. Increasing the addition of $ZrO_2$, it has been observed that the crystal growing temperature became higher.