• 한국세라믹학회지
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• 제27권2호
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• pp.288-296
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• 1990

Parent glasses for the experiments were prepared to be ratio of Li2O : Al2O3 : SiO2=4.5 : 25 : 70.5 as basic components, and TiO2 and ZrO2 in the mixing ratio of 1 : 1 were added as the nucleating agents, whose contents were increased in each sample. DTA, XRD, SEM, IR were observed, and thermal expansion and transmissivities were measured for the crystallized samples under the controlled heat-treatments. The transformation temperatures and the dilatometric softening temperatures in thermal expansion curves, and also the exothermic peaks in differential thermo-analytical curves were shifted to lower temperature. The crystal phase deposited through the heat-treatment was identified as ${\beta}$-quartz solid solution with XRD and IR analysis. The crystalline phases in oopactified samples were ${\beta}$-spodumene coexiting with ${\beta}$-quartz solid solution. The samples having more than 3% nucleating agents were transparent. The crystallized grain sizes were ranged 0.05 to 0.1$\mu\textrm{m}$. The crystallized transparent samples were exceeded 85% in the transmissivity.

• 한국산학기술학회논문지
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• 제3권3호
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• pp.183-188
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• 2002

Antibacterial glass ceramics composed of $5Li_2O{\cdot}36CaO{\cdot}20TiO_2{\cdot}27P_2O_5$ were Prepared. After ion exchange in the $AgNO_3$solution, crystallization phases were $AgTi_2(PO_4)_3$, $LiTi_2(PO_4)_3$ and $Ca_3(PO_4)_2$. In case of ion exchange, the crystallization phases started to be transformed from $LiTi_2(PO_4)_3$ to $AgTi_2(PO_4)_3$in 0.5 mole $AgNO_3$ solution and the transformation was almost completed in 1.0 mole. ion exchange rate of glass-ceramics powder, considering ion exchange time, was more fast than that of bulk. The bacteriostatic effect of the glass-ceramics on Staphyloroccus aureus and Salmonella typhi bacteria was more excellent than that of glass when the crystallization phase was transformed from LTP to AgTP.

• 자원리싸이클링
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• 제13권1호
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• pp.54-58
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• 2004

Wollastonite-type glass ceramics were prepared by milling and firing at various temperatures using an automobile waste glass and waste shell as starting materials. Powder mixture ground by disk-type ball mill for 3 hours was pressed into a disk. The pressed specimen was fired at $850^{\circ}C$,$950^{\circ}C$ and $1050^{\circ}C$ for 1 hour in air. From FE-SEM observation, with an increase of the firing temperature from $850^{\circ}C$ to $1050^{\circ}C$, whisker-type phase was grown to about 10 $\mu\textrm{m}$ in length. Specimen fired at $1050^{\circ}C$ showed the formation of well-crystallized whisker-type wollastonite grains and the highest compressive strength.

• Journal of Welding and Joining
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• 제21권1호
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• pp.107-113
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• 2003

Joining of $Si_3N_4$ to $Si_3N_4$ with crystallized glass solder was studied. $SiO_2-Al_2O_3-MgO$ glass with $P_2O_5$ as a crystallizing reagent was used as a solder. To improve the hish temperature toughness of joined specimen, two stage heat treatment was applied to Joined sample for the crystallization of joined layer, Two factors, i.e. thickness of soldered layer and crystallization were taken and thier effects on joining strength were investigated by a SEM-EDX observation of joined interface and bending strength both at room and elevated temperatures. Obtained results are summarized as follows: (1) Nitrogen diffused from $Si_3N_4$ to solder during the Joining process. Average amount of nitrogen in soldered layer depended on the thickness of the soldered layer and increased with decrease of the thickness. (2) Joining strength of the specimen having a thinner soldered layer was stronger than that of thicker layer. This can be mainly attributed to the difference of the nitrogen content in the soldered layer. (3) Higher content of nitrogen in solder brought forth higher viscosity of the solder. Hence the crystallization of the solder become more difficult in thinner layer of the solder than thicker one. (4) Thus, the effect of crystallization was evaluated mostly by the thicker layer specimen. Crystallization of soldered layer improved markedly the fracure strength of joining at higher temperatures than the softening temperature of glass solder.

• 한국세라믹학회지
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• 제16권1호
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• pp.21-25
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• 1979

This study is proposed to find an appropriate body for high expansion glass ceramics of ${Na}_2O-{Al}_2O_3-{SiO}_2$ system. The compositions of basic glasses are selected to be melted easily and to be crystallized into nepheline with various contents of alumina. The crystallization temperatures of basic glasses are determined by DTA. The crystals in the basic glasses developed by heat treatment are investigated by X-ray diffraction analysis, and thermal properties such as expansion coefficients, fusion points are measured. We find, therefore,that crystallization temperatures, crystal phases and thermal properties are affected by content of alumina.

• 한국세라믹학회지
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• 제30권3호
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• pp.236-242
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• 1993

As the fundamental research on preparation of fine single crystalline ferroxaplana by means of glass-crystallization methods using steel twin-roller, the properties of ferroxplana crystallized from glass were studied. Most of the specimens quenched by twin-roller at about 130$0^{\circ}C$ were glass phase, the crystallization of these glasses underwent multi-steps and ferroxplana phase was only stable in the temperature range of 88$0^{\circ}C$ to 95$0^{\circ}C$. Above 95$0^{\circ}C$ ferroxplana begines to be decomposed in glass. Ferroxplana had such magnetic properties as M8=29emu/g, MHC=166Oe, and Curie Temperature, Tc=610$\pm$5K.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.343-343
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• 2010

In this paper, Schottky barrier thin-film-transistors (SB-TFTs) with platinum silicide at source/drain region based on glass substrate were fabricated. Poly-silicon on glass substrates was crystallized by excimer laser annealing (ELA) method. The formation of pt-silicide at source/drain region is the most important process for SB-TFTs fabrication. We study the optimal condition of Pt-silicidation on glass substrate. Also, we propose this device as promising structure in the future.

• 한국레이저가공학회지
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• 제13권1호
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• pp.6-10
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• 2010

Crystallization of 100 nm thick amorphous silicon (a-Si) films on glass substrates was carried out by using a double laser irradiation method. Depending on a-Si deposition method or glass types, the quality of crystallized silicon film varies significantly. For a-Si films deposited with high concentration of impurities, large grains or high crystallinity can not be achieved. Crystallization with different a-Si deposition methods confirmed that for the polycrystallization of a-Si films on glass substrates, controlling the impurity density during substrate preparation is critical.

• 한국세라믹학회지
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• 제36권10호
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• pp.1087-1093
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• 1999

Bioglass which is one of the surface active bionmaterials has a good biocompatibility but a poor mechanical strength, In the present work therefore two types of fluoride-containing bioglasses were coated on an alumina to improve mechanical strength. Crystallization of the coating layer and the hydroxyapatite formation on the bioactive glass coatings in tris-buffer solution were studied. When bioactive glass coated alumina was heat-treated Na2CaSi3O8 crystal was formed on the layer at lower temperature while wollastonite(CaSIO3) was obtained at higher temperature. Hydroxyapatite forming rate on the coating layer with Na2CaSi3O8 crystal was delayed with SiO2 contents in glass composition. However the hydroxyapatite was developed in 20minutes regardless SiO2 contents when the coating layer crystallized into wollastonite. More amount of P3+ ions were leached out of the coating layer with wollastonite than that with Na2CaSi3O8 crystal while Na+ and Ca2+ ions were leached out more easily from the Na2CaSi3O8 crystal containing coating layer.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 추계학술대회 논문집
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• pp.18-21
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• 1995

In this study, crystallization, water swelling and dielectric properties of Li$_2$O-MgO-MgF$_2$-SiO$_2$System glass ceramics were investigated. Base glass melted at 1450$^{\circ}C$ and crystallized through heat treatment. The optimum heat treatment schedule was 460$^{\circ}C$ for nucleation and 640$^{\circ}C$, 1100$^{\circ}C$ for crystallization. The Principle crystalline phase was lithium fluorhectorite. Lithium fluorhectorite was the crystal phase which it was influenced water swelling. Samples progressed 2 minutes later they have rapid hydration at forced water swelling condition. Also value of dielectric constants have approximately 10 at 100kHz.