• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.814-817
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• 2003

The sintering behavior of $BaO-B_{2}O_{3}-ZnO$, which is Pb-free glass-ceramic system, was examined as functions of the composition and the amount and particle size of $Al_{2}O_{3}$ filler. Different kinds of modifiers were added and $Al_{2}O_{3}$ fillers with different particle sizes ($1.5{\mu}m$ and $4.5{\mu}m$) were added. The glass frit-filler composites were sintered in the temperature range $520{\sim}580^{\circ}C$. X-ray diffraction results revealed that some of the composites crystallized during sintering. Dielectric constant and thermal expansion coefficient the glass-ceramics were analyzed.

• Journal of the Korean Ceramic Society
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• v.23 no.6
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• pp.25-32
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• 1986

Phase spearated glass is heterogeneous in microscopic point of view and the heterogeneities affect the structures of glasses. In the present work the phase separation of $BaO-B_2O_3$ glass system was investigated and the effect of $P_2O_5$ on the phase separation and crystallization was also studied in the above system. Experiments such as scanning electron microscopy X-ray diffraction and infrared spectroscopy were performed. Phase separation with $B_2O_3$ rich phase matrix and BaO rich phase droplet was observed for the glasses containing less than 6 mole% of BaO while the opposite morphology of phase separation was found for the glasses containing more than 7 mole% of BaO. Phase separation region was extended up to the glass with 22mole% of BaO when the amount of $P_2O_5$ was increased. The heat-treated glasses crystallized to BaO.$4B_2O_3$$P_2O_5$ hindered the glass from the crystalli-zation.

• Journal of the Korean Ceramic Society
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• v.17 no.3
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• pp.151-157
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• 1980

Crystallization phenomena of glasses of fused natural basalt rocks were studied by DTA, X-ray phase analysis, electron microscopy, and other techniques. Crystallization was catalyzed by the addition of either chromite ore or $P_2O_5$, both up to 5 wt %. Various heat treatments were used, and their influences on controlling the microstructures and properties of the products were studied to develop high strength glass-ceramic material of the $CaO-Al_2O_3(Fe_2O_3)-MgO(FeO)-SiO_2$ system from the domestic basalts. Magnetite precipitates were found to be a nucleation initiator in every case of the crystallization. Diopside, anorthite, clinoenstatite and monticellite were identified as silicate crystalline phases contained in the crystallized products. The crystallite size was in the range of 0.1-2.5$\mu\textrm{m}$. The fine crystallites were approximately cubic, but large crystallites were either plate or needle shape. The thermal expansion coefficient, microhardness and modulus of rupture of glass-ceramics were ranged from 78.5 to 81.8$\times$10-7 cm/cm/$^{\circ}C$, from 820 to 930kg/$\textrm{mm}^2$, and from 1800 to 2800kg/$\textrm{cm}^2$, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1988.10a
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• pp.58-60
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• 1988

The dielectric properties of glass ceramics with BaTiO$_3$ crystallites are described. In this study measurements were made over the frequency range 1kHz-10MHz and temperature range $25^{\circ}C$-15$0^{\circ}C$. There are several minor constituents in the glass which needed to obtain the desired properties. The fluorine ion substitutes for oxygen in glass-crystallized BaTiO$_3$. And additions of Mg ion is used to shift the Curie temperature. We show the addition of Mg ion lowers the Curie point to about 323。K.

• Journal of Welding and Joining
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• v.25 no.3
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• pp.28-36
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• 2007

A bulk amorphous NiTiZrSiSn powder produced using an inert gas atomization was sprayed by kinetic spraying process that is basically a solid-state deposition process onto a mild steel substrate. They were successfully overlaid onto the mild steel substrate. In order to evaluate the tribological behavior of the kinetic sprayed NiTiZrSiSn BMG (Bulk Metallic Glass) coatings, a partially crystallized coating and a fully crystallized coating were prepared by the isothermal heat treatments. Tribological behaviors were investigated in view of friction coefficient, hardness and amorphous phase fraction of coating layer. Surface morphologies and depth in the wear tracks were observed and measured by scanning electron microscope and alpha-step. From the examination of the scratch wear track microstructure, transition from the ductile like deformation (micro cutting) to the brittle deformation (micro fracturing) in the scratch groove was observed with the increase of the crystallinity.

• Journal of the Korean Ceramic Society
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• v.48 no.1
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• pp.26-33
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• 2011

The glass in the system of CaO-$SiO_2-P_2O_5$ and the corresponding glass-ceramics are prepared for bone cements and the behaviors of the hardening and hydroxyapatite formation were studied for the glass and glass-ceramic powders. The glass crystallized into apatite, $\alpha$-wollastonite and $\beta$-wollastonite depending on the glass composition when they were heat-treated at $950^{\circ}C$ for 4 h. A DCPD (dicalcium phosphate dihydrate : $CaHPO_4{\cdot}2H_2O$) was developed when the prepared glass and glass-ceramic powders were mixed with 3M-$H_3PO_4$ solution. The DCPD (Ca/P=1.0) transformed to HAp (Ca/P=1.67) when the bone cement was soaked in simulated body fluid (SBF), and this HAp formation strongly depended on the releasing capacity of $Ca^{2+}$ ions from the glass and glass-ceramic cements. The glass-ceramic bone cement containing $\alpha$-wollastonite crystals showed faster transformation of DCPD to HAp than other glass-ceramics containing $\alpha$- and $\beta$-wollastonite crystals. No hydroxyapatite was observed when the glass-ceramic bone cement containing apatite crystals (36P6C) was soaked in SBF even for 1 month, because no $Ca^{2+}$ ion can be released from the stable apatite crystals.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.3
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• pp.358-364
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• 2013

Borosilicate glass(GVB-Solutions in glass, 2mm, Germany) was prepared in the composition of $80.4SiO_2-4.2Na_2O-2.4Al_2O_3-13.0B_2O_3$. The 2-step crystallization was performed around $584^{\circ}C$ of glass transition temperature ($T_g$), and $774^{\circ}C$ of crystallization temperature($T_c$). The maximum nucleation rate was $8.8{\time}10^9/mm^3{\cdot}hr$ at $600^{\circ}C$ and the maximum crystal growth rate was 3.5nm/min at $750^{\circ}C$. The maximum mechanical properties were observed at 22.8% of volume fraction, the strength, hardness and fracture toughness was 555MPa, $752kg/mm^2$, $1.082MPa{\cdot}mm^{1/2}$. The crystal size of 177nm which has volume fraction of 22.8% showed maximum strength of 562MPa, it is about 157% higher than parent borosilicate glass. From these results, the crystallized borosilicate glass can be applied weight lighting of bullet proof materials.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.10
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• pp.797-802
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• 2009

Large area crystallization of amorphous silicon thin-films on glass substrates is one of key technologies in manufacturing flat displays. Among various crystallization technologies, the Joule induced crystallization (JIC) is considered as the highly promising one in the OLED fabrication industries, since the amorphous silicon films on the glass can be crystallized within tens of microseconds, minimizing the thermally and structurally harmful influence on the glass. In the JIC process the metallic layers can be utilized to heat up the amorphous silicon thin films beyond the melting temperatures of silicon and can be fabricated as electrodes in OLED devices during the subsequent processes. This numerical study investigates the heating mechanisms during the JIC process and estimates the deformation of the glass substrate. Based on the thermal analysis, we can understand the temporal and spatial temperature fields of the backplane and its warping phenomena.

• Journal of the Korean Ceramic Society
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• v.31 no.11
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• pp.1337-1345
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• 1994

Glasses in the system of 45CaO-25TiO2-30P2O5 containing 1 mole% of M2O(M=Li, Na, K) were melted and crystallized. And their crystal phases were Ca3(PO4)2, CaTi4(PO4)6, and TiO2. Porous glass-ceramics with skeleton of two crystal phase CaTi4(PO4)6 and TiO2 were prepared by selective leaching of Ca3(PO4)2 with 0.1 N-HCl. Glass transition temperature(Tg) and crystallization temperature(Tc) were decreased by addition of 1 mole% alkali metal oxide. Pore size of porous glass-ceramics was increased with increasing heat treatment temperature and its dependence on heat treatment temperature was decreased with addition of Na2O and K2O. It was found that porous glass-ceramics of parent glass and containing 1mole% M2O(M=Li, Na, K) composition had maximum specific surface area, porosity and maximum of crystallzed phase by heat treatment at 80$0^{\circ}C$, 76$0^{\circ}C$, 78$0^{\circ}C$, 80$0^{\circ}C$ respectively.

• Journal of the Korean Ceramic Society
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• v.35 no.7
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• pp.665-670
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• 1998

Ferroelectric anomaly in PbO-{{{{ { {B }_{2 }O }_{3 } }}-{{{{ {TiO }_{3 } }}-BaO glasses which is observed in DAT measurements was in-vestigated together with the effect of BaO content on the shift of Cuire temperature. The temperature where the ferroelectric anomaly apperars on cooling in DTA decreased in proportion with increasing BaO content,. For as-crystallized samples the ferroelectric anomaly was not observed on heating but on cooling whilist for powder samples leached chemically from the crystallized samples both endothermic and ex-otehrmic peaks were observed. This fact suggests that the appearance of the ferroelectric anomaly in DAT largely depends on glassy phases surrounding individual {{{{ {PbTiO }_{3 } }} crystals rather than effects of grain size and crystallinity.