• 한국세라믹학회지
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• 제25권5호
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• pp.431-436
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• 1988

The properties of scid-resistance to boiling HCl, thermal expansion coefficient and softening temperature of mother glass and glass-ceramic of LAS systems were investigated at the contents of SiO2 varing from 57 to 67wt%. The nucleation and growth of crystalline phase of LAS compositions were carried out at 50$0^{\circ}C$ and $700^{\circ}C$. The crystalline phase jconsists of lithium alumino silicate, lithum meta silicate, lithium disilicate, $\alpha$-crystobalite and $\alpha$-quartz. Lithium alumino silicate(virgilite) is the major crystalline phase in the glass ceramics. The degree of acid resistant property was increased in proportion with the silica content for both glass and ceramics. Glass-ceramic gives lower acid-resistance and thermal expansion coefficient while softening temperature shows higher for glass-ceramic than for mother glass.

• 한국세라믹학회지
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• 제31권7호
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• pp.784-794
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• 1994

Though spodumene have a law theraml expension and good thermal shock resistance, its sintering temperature is too close to its melting point in the application for industral purpose. Solving the problems, impurities within the silicate minerals act as a frit during firing, so its densification is expected through enlargement of sintering temperature range. By the heat treatment of starting materials, mixtures of silicate mineral, lithium carbonate, if necessary SiO2 or Al2O3 were added for stoichiometric correction, in the range of 1000~125$0^{\circ}C$ for 10 hrs, $\beta$-spodumene single phase was synthesized. Mixtures with sillimanite group minerals, $\beta$-spodumene was formed at 120$0^{\circ}C$ or 125$0^{\circ}C$ via intermediate phases of petalite, Li2SiO3 and LiAlO2. For the case of kaolin group minerals, synthesis were completed at 110$0^{\circ}C$ for Hadon pink kaolin, 120$0^{\circ}C$ for New Zealand white kaolin, When pyrophyllite group minerals were used, those were at the range of 1000~125$0^{\circ}C$. Spodumene was completed at lowest temperature, 100$0^{\circ}C$ from the mixture of Wando pyrophyllite among them. Microstructure of synthesized powders showed the inrregular lump shape such as densed crystallines.

• E2M - 전기 전자와 첨단 소재
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• 제10권3호
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• pp.284-288
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• 1997

FT-IR and FT-Raman spectra were measured for 15Li$_{2}$O.3Al$_{2}$O$_{3}$.78SiO$_{2}$. 4K$_{2}$O glass system after UV irradiations. Optimum UV irradiation time of Li$_{2}$O.SiO$_{2}$ crystalline phase was 60 seconds and crystalline phase of Li$_{2}$O.SiO$_{2}$ was leached out on 5% HF. 977 cm$^{1}$ band of FT-Raman spectra can be attributed to two-non bridging oxygen in unit cell for 1 hour and optimum crystallization was confirmed for 3 hrs, 630.deg. C.

• E2M - 전기 전자와 첨단 소재
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• 제10권2호
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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.

• 한국재료학회지
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• 제4권6호
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• pp.611-619
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• 1994

본 연구는 Lithium Alumino Silicate 기본계에 핵형성제로 $TiO_{2}$와 $ZrO_{2}$를 사용하여 기본유리를 제조하고 열처리에 따른 $\beta$-quartz고용체의 미결정 형성과정을 분석하였다. 또한 $\beta$-quartz고용체의 형성에 따른 열적 특성과 광학적 특성을 비교하였다. 그 결과, 기본 유리의 열팽창 계수는 $45\sim 55 \times 10^{-7} \textrm{cm}/^{\circ}C$였으며, 결정화 시편의 열팽창 계수는$ -8\sim +8 \times 10^{-7}\textrm{cm}/^{\circ}C$ ($25^{\circ}C \sim 525^{\circ}C$)였다. $900^{\circ}C$이하에서 열처리된 Glass Cermics의 결정은 $\beta$-quartz 고용체가 형성되었고, 결정의 크기가 0.21$\mu \textrm{m}$를 초과하지 않았으며, 최고의 투광도는 80%이상을 나타냈다. RO성분을 MgO와 ZnO를 사용한 경우보다 MgO 단독으로 사용한 시편을 결정입자의 크기가 온도에 의존하지 않고 일정함을 나타냈으며, ZnO의경우는 입자의 크기가 최소값(0.18$\mu \textrm{m}$)을 보이며 온도의존성이 크게 나타냈다.

• 마이크로전자및패키징학회지
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• 제7권2호
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• pp.43-46
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• 2000

Nd:YAG laser of 355 nm wavelength, which amounts to 3.5 eV, produced by a harmonic generator was used to create Ag metallic particles as seeds for nucleation in photosensitive glass containing $Ag^+$ and $Ce^{3+}$ . The pulse widths and frequency of the laser were 8ns and 10 Hz, respectively. For crystalline growth, heat-treatment following laser irradiation was carried out at $570^{\circ}C$ for 1h. Then, the $LiAlSi_3O^8$ crystal phase appeared in the laser irradiated lithium aluminum silicate glass. We present the effect of laser-induced nucleation compared with spontaneous nucleation by heat treatment fur crystallization in the glass.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2000년도 Proceedings of 5th International Joint Symposium on Microeletronics and Packaging
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• pp.112-117
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• 2000

Nd:YAG laser of 355nm wavelength, which amounts to 3.5eV, produced by a harmonic generator was used to create Ag metallic particles as seeds for nucleation in photosensitive glass containing Ag+ and Ce3+. The pulse widths and frequency of the laser were 8ns and 10Hz, respectively. For crystalline growth, heat-treatment following laser irradiation was carried out at $570^{\circ}C$ fur 1h. Then, the LiAlSi3O8. crystal phase appeared in the laser irradiated lithium aluminum silicate glass. We present the effect of laser-induced nucleation compared with spontaneous nucleation by heat treatment for crystallization in the glass.