• Transactions of Materials Processing
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• v.15 no.3 s.84
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• pp.213-219
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• 2006

To improve the strength of glass is being studied in order to contribute to weight saving of flat panel displays. Generally, the strength achieved of glass-ceramics is higher as is the fracture toughness by the formation of a heterogeneous phase inside glass. In this study, Ag-doped $45SiO_2-24CaO-24Na_2O-4P_2O_5\;and\;70SiO_2-10CaO-24Na_2O-10TiO_2$ glasses were irradiated to strengthen by crystallization using femto-second laser pulse. XRD, Nano-indenter and SEM etc., irradiation of laser pulse without heat-treated samples was analyzed. Samples irradiated by laser had higher value($4.4{\sim}4.56^*10-3Pa$) of elastic modulus which related with strength of glass than values heat-treated samples and these are $1.2{\sim}1.5$ times higher values than them of mother glass. This process can be applicable to the strengthening of thinner glass plate, and it has an advantage over traditional heat-treatment and ion-exchange method.

• Journal of the Microelectronics and Packaging Society
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• v.5 no.1
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• pp.31-38
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• 1998

저온소결기판용 Glass-ceramics를 제조하기 위해 LiO2-MgO-MgF2-SiO2계 조성에 서 B2O3첨가가 결정화 특성 및 물성에 미치는 영향을 고찰하였다. 145$0^{\circ}C$에서용융하여 제조 한 모유리의 핵형성 온도와 결정화 온도를 결정하기 위해 TMA와 DTA분석을 실시하였다. 결정화시킨 유리의 결정상과 미세구조를 관찰하기 위하여 XRD와 SEM관찰을 실시하였다. Water swelling을 통해 Glass-ceramics powder를 제조하였으며 제조한 powder의 평균입자 크기는 8.32$\mu$m였다.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.2 s.35
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• pp.141-147
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• 2005

Nanomaterial $TiO_2-SiO_2$ was synthesized by hydrolysis and condensation process using 2-propanol(2-PrOH) and was characterized by FT-IR, DSC, XRD and FE-SEM. FT-IR spectra were measured to investigate Ti-0-Si absorption peak. DSC thermal analysis results appllied to Ozawa equation were used to calculate to activation energy of crystallization. It was found that the changes of X-ray diffraction patterns and FWHM obtained XRD measurement depended on calcination temperature. In FE-SEM analysis, particle size changed by quantity changes of Ti-alkokide.

• Journal of the Korean Ceramic Society
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• v.37 no.12
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• pp.1221-1228
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• 2000

TiO$_2$를 포함한 희토류 알루미노 규산염계 (NAS: Nd$_2$O$_3$-Al$_2$O$_3$-SiO$_2$) 유리의 상분리 현상에 대하여 연구되었다. 0~10wt%의 TiO$_2$포함한 NAS 조성은 유리전이온도(T$_{g}$) 부근에서 열처리하여 HF로 부식 후 주사전자현미경, 라만 및 IR 분석기로 상분리가 조사되었다. 그 결과로 상분리한 내부결정화는 8wt% 이상의 TiO$_2$를 포함한 NAS 조성에서 나타났다. 어닐링후 T$_{g}$ 부근에서 열처리의 결과는 투명 연핑크색의 유리를 불투명의 연푸른 우유빛 색으로 변하게 하였으며, Si와 Nd-Ti가 각각 풍부한 10$mu extrm{m}$ 이상과 0.1$\mu\textrm{m}$ 이하의 크기인 구형상의 영역으로 균일한 다상분리를 일으켰다. Nd$_2$O$_3$-Al$_2$O$_3$-SiO$_2$-TiO$_2$계에서 상분리는 내부 결정화와 관련하여 매우 중요한 인자로 확인되었다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.4
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• pp.558-563
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• 1996

Fracture strength of $Si_{3}N_{4}/20$ vol% SiC nanocomposites with fifferent sintering additives was measured. Strength of nanocomposites with 6 wt% $Y_{2}O_{3}$ and 2 wt% $Al_{2}O_{3}$ as sintering additives was higher at room temperature but significant strength degradation at elevated temperature was occured due to the softening of grain boundary phase. Fracture strength of 8 wt% $Y_{2}O_{3}$ doped sample was higher than that of $Al_{2}O_{3}$ added sample at $1400^{\circ}C$. The retention of high temperature strength in 8 wt% $Y_{2}O_{3}$ doped sample can be attributed to high softening temperature and crystallization of grain boundary glassy phase.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.4
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• pp.190-195
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• 2002

NaX zeolite crystals of a uniform particle size of 50 $\mu$m were grown by continuous crystallization method from seed crystals (10~20 $\mu$m) added into a 0.5~2.0 g mother liquor having a composition $3.5Na_2O : Al_2O_3: 2.1SiO_2: 1000H_2O$. In order to investigate the crystal growing by continuous method, the mother solution was supplied after 7 days, 5 days, 3 days and 1 day, respectively. The seeding resulted in an increase in the fraction of large crystals compared with unseeded batches and successfully led to an uniform NaX zeolite crystal. It was postulated that the seeding in the synthesis mixture leaded out increase of surface area for physical contact reaction and directed growth of seed crystal without the nucleation in the synthesis gel.

• Journal of the Korean Ceramic Society
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• v.37 no.2
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• pp.168-173
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• 2000

YMnO3 thin films were prepared on Pt/Ti/SiO2/Si substrate by chemical solution deposition method. The films were crystallized by heat-treatment at 85$0^{\circ}C$ for 1 hour. Effects of an annealing atmosphere(O2, Ar, vacuum) on the crystallization behavior and electridcal properties were investigated. YMnO3 thin films annealed under Ar atmosphere showed a superior crystallinity and a very strong c-aix preferred-orientation which was a polar axis. Leakage current density of the films decreased with lowering oxygen partial pressure of the annealing atmosphere. C-V and P-E ferroelectric hysteresis were observed only in the thin film heat-treated under Ar atmosphere.In order to prepare YMnO3 thin films having both low leakage current and ferroelectricity, the annealing atmsphere should be kept under a proper oxygen partial pressure which was about 1 Pa in this work. Leakage current density at 1 volt, dielectric constant($\varepsilon$r), remanent polarization(Pr), and coercive field(Ec) were 1.7$\times$10-8 A/$\textrm{cm}^2$, 25, 1.08$\mu$C/$\textrm{cm}^2$, and 100 kV/cm, respectively.

• Journal of Ceramic Processing Research
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• v.22 no.5
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• pp.568-575
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• 2021

Glass-ceramic glazes were prepared using a CaO-MgO-Al2O3-SiO2 system and were used to fabricate low-temperature firing,high-hardness glazes in ceramic tiles. Additives (B2O3) and a nucleating agent (TiO2) were added to the glaze, and crystallineglazes were obtained by sintering at 1000 ~ 1100 oC for 30 or 60 min. X-ray diffraction analysis of the glazes suggested thatcordierite (Mg2Al4Si5O18) and anorthite (CaAl2Si2O8) crystal phases were present, and the peak intensity of the cordieritecrystal phase increased with increasing sintering temperature. All samples showed high crystallinities of 70% or more,irrespective of sintering temperature or time. The glaze density increased with increasing sintering temperature and decreasedat 1100 oC. The Vickers hardness test results of the glazes indicated high hardness values of 6.79 and 6.77 GPa after 30 minheat treatment at 1000 oC and 60 min at 1050 oC, respectively. Glass-ceramic glaze with high hardness at low temperature wasfabricated through crystallization of glaze for tiles.

• Journal of the Korean Ceramic Society
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• v.29 no.1
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• pp.9-14
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• 1992

Some of non-isothermal analysis methods are applied to CaO-MgO-Al2O3-SiO2 glass system to find the kinetics parameters of crystallisation, activation energy, Avrami component and frequency factor. The results using the non-isothermal analysis were compared to that of microstructure experiment. Analysis of the result has enabled to some methods to be to recommend as being the most appropriate equation to use in a glass system. It was shown that in the thermal analysis using the non-isothermal method of Kissinger, Augis-Bennett, Bansal, and Marotta, the calculation of activation energy is not much different, while Avrami component and frequency factor are different from applied each methods.

• Journal of the Korean Ceramic Society
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• v.39 no.5
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• pp.438-445
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• 2002

In this study, the glass frit of $PbO-TiO-2-SiO_2-BaO-ZnO-Al_2O-3-CaO-B_2O_3-Bi_2O_3-MgO$ system was manufactured. The glass was melted at $1,400{\circ}C$, quenched and attrition-milled. The glass frit powder was pressed and fired for 2h at the range of $750~1,000{\circ}C$. The crystallization of glass frit began at about $750{\circ}$ and at low temperature, the main crystal phases were hexagonal celsian($BaAl_2Si_2O_8$) and alumina. As the firing temperature increased, the crystal phases of monoclinic celsian, zinc aluminate, zinc silicate, calcium titanium silicate and titania appeared. And the increase of firing temperature led to transformation of hexagonal celsian to monoclinic. The only glass frit containing 15wt% PbO had the crystal phase of solid solution of $PbTiO_3-CaTiO_3$. At the frequency of 1 MHz, the dielectric constant of glass frit crystallized was in the range of 11~16 and the dielectric loss less than 0.020. But the glass frit containing 15wt% PbO had the dielectric constant of 17~26 and loss of 0.010~0.015 because of crystal phase of solid solution of $PbTiO_3-CaTiO_3$.