• 한국세라믹학회지
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• 제27권4호
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• pp.521-528
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• 1990

Li2O.2SiO2 glass-ceramics were made from the melt by the nucleation and growth treatment. The optimum nucleation temperature and time were determined from DTA curves of as-quenched and thermally treated glasses, and found to be 44$0^{\circ}C$ and 3hrs. The optical microscopic technique was also used to support this result. The volume fractions of crystals present in the partially crystallized specimens were measured using the optical microscopy and the amorphous X-ray scattering methods. The degree of crystallization increased with increasing the crystallization temperature and time. The crystalline phase identified by X-ray diffraction was lithium disilicate. As the crystallinity increased up to 95%, the transmittance of glass-ceramics was decreased linearly. It was also found that for the same heat treatment condition (575$^{\circ}C$, 30min), a thicker specimen showed higher transmittance, presumably due to less crystallinity.

• 한국세라믹학회지
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• 제42권2호
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• pp.81-87
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• 2005

[ $BaTiO_3$ ]계 유전체 모재료에 대하여 $Al_{2}O_{3}$와 CaO 조성이 소량 포함된 lithium-borosilicate계 유리 프릿을 $5\~15wt\%$ 적용함으로써 LTCC용 내장 캐패시터로 적용 가능한 조성을 개발하였다. 이를 위하여 먼저, 화학적으로 안정하고 저온소성효과가 탁월한 유리 프릿 조성물을 설계하고 이를 유전체 모재료에 적용하여 저온소성특성 및 유전특성을 평가하였다. $BaTiO_3$ 세라믹스를 모재료로 하는 경우 유리 프릿을 5wt$\%$ 첨가하였을 때 $925^{\circ}C$에서 $95\%$ 정도의 상대밀도 값을 나타내었으며, 이 경우 유전율 990, 유전손실 $3.1\%$의 유전특성을 나타내었다. $(Ba,Ca)(Ti,Zr)O_3$ 세라믹스를 모재료로 하여 유리프릿을 10 wt$\%$ 첨가한 경우는 $875^{\circ}C$의 소결온도에서 상대밀도가 $95\%$ 이상이며 기공율 $0.5\%$ 이하인 소결특성을 나타내었고, 700 이상의 유전율 및 $2\%$ 내외의 유전손실 값을 가지는 것으로 측정되었다.

• 한국세라믹학회지
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• 제46권5호
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• pp.488-492
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• 2009

Porous frit-bonded SiC ceramics were successfully prepared at a temperature as low as $800^{\circ}C$ from SiC, frit, and microbeads (glass or polymer). The effects of SiC starting particle size and microbead addition on microstructure, porosity, and flexural strength were investigated. The addition of hollow glass microbead improved the strength of frit-bonded SiC ceramics without the loss of porosity by acting additional binder phase between SiC grains. The 65 ${\mu}m$-sized SiC resulted in lower porosity and higher strength than 50 ${\mu}m$-sized SiC because of higher packing density. Typical flexural strengths of frit-bonded SiC were 23 MPa at 46% porosity and 19 MPa at 49% porosity.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2005년도 제24회 춘계학술대회논문집
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• pp.112-115
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• 2005

본 연구는 램제트 엔진의 돔포트 커버의 소재로 사용 될 첨단 그라스 세라믹(MACOR) 소재에 대한 동적 파괴인성 시험을 목적으로 한다. 다양한 노치반경의 시험편에 대하여 스트레인게이지법을 사용한 정적과 동적 파괴인성 시험을 수행하였다.

• 한국세라믹학회지
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• 제51권4호
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• pp.312-316
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• 2014

The joining behavior of forsterite ceramics to SUS304 alloy using $8PbO-78Bi_2O_3-8B_2O_3-4ZnO-2SiO_2$ (wt%) system glass frit was investigated. The contact angle was smaller than $90^{\circ}$ at a temperature of $460^{\circ}C$. Redox reaction at the interface between forsterite and SUS304 was found to appear when the electrons in the metal part moved toward the glass part and the oxygen ions in glass moved to the metal side. The decrease of the surface tension due to the PbO solubility on the forsterite side contributed to the better wetting behavior at low temperature.

• 한국세라믹학회지
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• 제32권12호
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• pp.1331-1336
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• 1995

The glass-ceramics for ferro-electric were made from compositions of 70PbO.16TiO2.8SiO2.4B2O3.2AlPO4 (wt%) and 67.5PbO.20TiO2.8.5SiO2.2B2O3.2AlPO4 (wt%). The crystallization kinetics for PbTiO3 crystalline phase formation from glass was studied using non-isothermal DSC techniques. The values of activation energy, ΔE using variables of heating rate and temperature were calculated at various reaction fractions obtained from peak area over DSC. The results indicated that activation energy was lowest at 60% reaction fractions and the activation energy of glass containing 20.0 wt% TiO2 is higher than that of glass containing 16.0 wt% TiO2. The crystallization mechanism was three dimensional growth (n=4).

• 한국콘텐츠학회논문지
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• 제15권9호
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• pp.384-394
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• 2015

본 연구에서는 원통형 지르코니아 코어에 다섯 종류의 지르코니아 비니어 세라믹을 축성하여 push-전단결합강도를 측정하고, 비니어 세라믹의 이축굽힘강도와 지르코니아 글라스 라이너 처리에 따른 전단결합강도 차이를 알아보고자 하였다. 지르코니아 비니어 세라믹은 piston-on-three-ball test로 이축굽힘강도를 측정하였고, 지르코니아 실린더 코어와 비니어 세라믹은 push-shear test로 결합강도를 측정하였으며, 결과값은 이원분산분석을 사용하여 분석하였다. 이축굽힘강도는 Cercon ceram kiss (CE)군에서 가장 높게 측정되었고 전단결합강도는 글라스 처리군과 Triceram(TR)군이 높게 측정 되었으며 Creation ZI(CR)군에서 가장 낮은 값이 측정 되었다. 실험군에서 지르코니아 라이너 처리군이 라이너 처리하지 않는 군보다 전단결합강도가 높게 나타났으며 통계적으로 유의한 차이를 보였다(P<0.05). 따라서 지르코니아 라이너 처리는 지르코니아와 비니어 세라믹의 결합강도를 향상시킬 수 있는 것으로 사료된다.

• 한국전기전자재료학회논문지
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• 제26권8호
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• pp.614-619
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• 2013

Recently, remote phosphor is reported for white LED enhancing of phosphor efficiency compared with conventional phosphor-based W-LED. In this study, Remote phosphor was produced by screen printing coating on glass substrate with phosphor contents rated paste and heat treatment. The paste consists of phosphor, lowest softening glass frit and organic binders. Remote phosphor can be well controlled by varying the phosphor content rated paste. After mounting remote phosphor on top of blue LED chip, CCT, CRI, and luminance efficiency were measured. The measurement results showed that CCT, CRI, and luminance efficiency were 6,645, 68, and 1,16l m/W in phosphor 80 wt.% remote phosphor sintered at $600^{\circ}C$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.260-260
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• 2007

Low-temperature sintering and dielectric properties of the $1-xBiNbO_4-xZnNb_2O_6$ ceramics (x=0.3, 0.5, and 0.7) with 10 wt% zinc borosilicate (ZBS) glass was investigated as a function of the substitution of $ZnNb_2O_6$ with a view to applying this system to LTCC technology. The all composition addition of 10 wt% ZBS glass ensured a successful sintering below $900^{\circ}C$. The the amount of $ZnNb_2O_6$ on $ZnNb_2O_6$ ceramics increased the $Q{\times}f$ values, but it decreased the sinterability and dielectric constant due to the higher $Q{\times}f$ value and sintering temperature of $ZnNb_2O_6$ than that of $ZnNb_2O_6$ ceramics. The increase of $ZnNb_2O_6$ content from 0.3 to 0.7 in the $1-xBiNbO_4-xZnNb_2O_6$ ceramics with 10 wt% ZBS glass sintered at $900^{\circ}C$ demonstrated 30~20 in the dielectric constant (${\varepsilon}_r$), 3,500~4,500 GHz in the $Q{\times}f$ value.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.91-91
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• 2008

$SnO_2-B_2O_3-P_2O_5$ system were prepared by melt-quenching technique in the compositional series containing 50, 55 aod 60mol.% of $SnO_2$. A large glass-forming region was found at the phosphate side of the ternary system with homogeneous glasses containing up to 5-25mol.% of $B_2O_3$. For these glasses, thermal expansion coeffient($\alpha$), glass transition temperature(Tg), and glass softening temperature(Ts), were determined. The values a decrease with increasing $B_2O_3$ content, while Tg and Ts increased. The reason for the observed changes is local structure of the glasses. Local structure of the glasses was investigated by Raman and FT-IR measurements, suggesting that the number of bridging oxygens decreased whereas the non-bridging oxygen concentration increased with increasing $SnO_2$ content in the glasses.