• Journal of the Korean Ceramic Society
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• v.46 no.5
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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.

• Journal of the Korean Ceramic Society
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• v.37 no.4
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• pp.302-307
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• 2000

The objective of this study was to investigate the sintering behavior, crystallization characteristic of glass-ceramic and optimal sintering condition on the glass/ceramic composite for fabricating substrate of LTCC. Glass/ceramic composite was made from alumina powder and glass frit, which was composed of SiO2-TiO2-RO-PbO/(R: Ba, Sr, Ca), and was sintered for 0, 30, 60minutes in the temperature range from 700$^{\circ}C$ to 1000$^{\circ}C$. Properties of frit and glass/ceramic compsoite were analyzed by DTA, XRD, SEM and Network Analyzer and so on. Main sintering mechanism was densification occurred above 730$^{\circ}C$ by viscous flow and crystallization starting about 780$^{\circ}C$ affected sintering also. So viscous flow was affected by sintering temperature, duration time, and creation of crystallization phase etc. From this study, it was possible to fabricate glass/ceramic composite by changing sintering temperature and duration time.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.4
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• pp.619-625
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• 1998

The effect of softening point and glass amount of glass frit on the sintering behavior of low temperature cofirable glass/ceramic composites was studied and according to these results, glass/ceramic composites with high sintered density was fabricated. The density of composites was increased as the glass amount was increased. In case of using the glass with low softening point, the deformation of specimen was occurred though the ratio of the glass amount in the specimen was low. But, in case of using the glass with high softening point, the sintered density of composites was increased in accordance with glass amount. With the specimen of high softening point, the deformation was not happened. Therefore, it was found that the densification was progressed continuously in high glass amount. From the study on the effect of softening point of glass on sintering behavior, the suitable softening point and glass amount for fabrication of glass/ceramic composites can be anticipated. When glass frit with softening point of $790^{\circ}C$ was chosen according to this result, low temperature cofirable glass/ceramic composites with high density (97%) at $900^{\circ}C$ was fabricated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.335-338
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• 1998

The effect of glass flit addition on microwave dielectric properties of BaTiO$_3$-3TiO$_2$ ceramic was studied. Addition of glass frit to this system obtained sintered sample below sintering temperature 105$0^{\circ}C$. At BaTiO$_3$-3TiO$_2$+ g1ass frit 3wt% + BaWO$_4$6 wt%m, this ceramic showed excellent microwave properties of dielectric constant 34, Q$\times$f 8,100, temperature coefficient of resonant frequency 4 ppm/$^{\circ}C$ .

• Journal of the Korean Ceramic Society
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• v.41 no.10 s.269
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• pp.783-787
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• 2004

Microwave dielectric properties and the microstructure of $Ba_5Nb_4O_{15}$ ceramics with $PbO-B_2O_3-SiO_2$ glass frit were investigated to reduce the sintering temperature of $Ba_5Nb_4O_{15}$ ceramics as a function of the amount of glass frit from $0.5wt\%$ to $10wt\%$ and the sintering condition. The sintered density and the microwave dielectric properties of $Ba_5Nb_4O_{15}$ ceramics were remarkably changed with the amount of glass fit which existed as a liquid phase and assisted the densification. $Ba_5Nb_4O_{15}$ with $3wt\%$ $PbO-B_2O_3-SiO_2$ glass frit sintered at $900^{\circ}C$ for 2 h showed dielectric constant (K) of 41.4, a quality factor (Q $\times$f) of 13,485 GHz, and a Temperature Coefficient of resonant Frequency (TCF) of 9 ppm/$^{\circ}C$. Due to no trace of physical and chemical reaction between this composition and Ag electrode cofired at $900^{\circ}C$ for 2 h, this ceramics can be a good candidate for the multilayer dielectric filter.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.3
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• pp.200-207
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• 2011

Abstract: The effect of lead free glass frit compositions on the properties of thick film conductor and resistor pastes were investigated. Two types lead free frits, HBF-A(without $Bi_2O_3$) and HBF-B(with $Bi_2O_3$) were made from $SiO_2$, $B_2O_3$, $Al_2O_3$, CaO, MgO, $Na_2O$, $K_2O$, ZnO, MnO, $ZrO_2$, $Bi_2O_3$. And Ag based conductor pastes and $RuO_2$ based resistor paste were prepared by mixed with these frits and functional phase(Ag and $RuO_2$), and organic vehicle. The properties of thick film conductor and resistor sintered at $850^{\circ}C$ were studied after printing on $Al_2O_3$ substrate. The morphology of the sintered films surface were SEM and EDS were carried out to analysis the chemical composition on resistor surface and state of Ru atom in frit matrix.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.107.2-107.2
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• 2012

We used the electrophoretic deposition (EPD) process to fabricate a glass composite and investigated the EPD parameters to find the optimum deposition time by understanding the relationship among the process parameters of zeta potential (ZP), pH, deposition yield and saturation point. A binder and a dispersing agent were mixed properly with glass frit ($0.2{\sim}25{\mu}m$, d50=$8.77{\mu}m$) in an ethyl alcohol medium for the preparation of the slurry. The pH and ZP were in an inverse relationship to each other due to the generation of $H_3O^+$ ions with the addition of the dispersing agent in the slurry. The acidic nature of the dispersing agent was resulted in a decrease of the pH and an increase of the ZP. Otherwise, the pH increased with the addition of the glass frit in the slurry because $H_3O^+$ ions were absorbed on the glass frit. Therefore, the $OH^-$ ions correspondingly increased. The saturation point of EPD was strongly correlated with the variation of the pH in the slurry; this is caused by a chemical reaction between the ethyl alcohol and the ions that make up the glass frit. An adjustment of the pH variation and the saturation point in the slurry can be established with respect to the optimum deposition time in the slurry.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.310-310
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• 2007

Mg-Si-O계 세라믹스에 glass frit 조성을 첨가하여 저온에서의 소결 특성 및 마이크로파 유전 특성을 연구하였다. 기존의 Mg-Si-O계 세라믹스는 우수한 유전특성을 가지고 있으나 높은 소결온도로 인하여 LTCC용 기판 소재로 적용이 어려웠다. 본 연구에서는 MgO, $SiO_2$를 이용하여 $Mg_2SiO_4$을 합성한 후, $B_2O_3-ZnO-Na_2O-SiO_2-Al_2O_3$계 glass 조성을 20~40wt%로 첨가하여 소결온도를 감소시켜 LTCC 기판 소재로서의 적용성을 고찰하였다. glass frit 함량이 증가함에 따라 밀도($g/cm^3$) 및 유전율(${\varepsilon}_r$)은 증가하였고 품질계수($Qxf_0$)값은 감소하였다. glass frit 함량이 40wt%일때 $900^{\circ}C$에서 1시간 소결한 소결체의 유전톡성은 유전율 (${\varepsilon}_4$) = 6.5. 품질계수 ($Qxf_0$) = 4,000(GHz), 온도계수 $(\tau_t)\;=\;{\pm}\;10ppm/^{\circ}C$로 우수한 특성을 확인하였다.

• Journal of the Korean Ceramic Society
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• v.40 no.7
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• pp.644-651
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• 2003

Effects of additives on electrical properties and microstructure of MLCC X7R dielectrics have been investigated. The additives of glass frit or oxide form were added in the same main composition by the different powder processing conditions. As a result of the dielectric property and microstructure analysis, the composition having the glass layer with dopant concentration gradient showed the excellent dielectric properties. The MLCCs were fabricated with the excellent composition and all dielectric properties satisfied the X7R requirements.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.363-364
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• 2005

LTCC(low temperature co-fired ceramics)용 glass/ceramic 복합체를 제조하기 위해 3종류 의 glass를 선정하고 filler로 $Al_2O_3$ 와 $TiO_2$를 사용하여 glass frit에 따른 소결 및 유전 특성에 대하여 조사하였다. Glass frit은 lead-borosilicate(PBS), zinc-borosilicate(ZBS), bismuth-borosilicate(BBS) glass 조성을 사용하였고 1100~$1400^{\circ}C$에서 melting시킨 후 quenching하여 frit화하였다. $Al_2O_3$와 $TiO_2$ filler에 10~50 vol%로 glass frit을 각각 혼합한 후 600~$950^{\circ}C$에서 2시간 동안 소결한 결과 50 vol% glass frit 일 때 $900^{\circ}C$ 이하에서 소성이 가능하였다. 유전특성은 $900^{\circ}C$에서 $Al_2O_3$-50vol%PBS($\varepsilon_{r}$=8.8, $Q{\times}f_o$=4,900, $\tau_f$=-24), $Al_2O_3$-50vol% ZBS($\varepsilon_{r}$=5.7, $Q{\times}f_o$=17,800, $\tau_f$=-21), $Al_2O_3$-50vol%BBS($\varepsilon_{r}$=11.1, $Q{\times}f_o$= 2,080, $\tau_f$=-48), $TiO_2$-50vol%PBS($\varepsilon_{r}$=18.6, $Q{\times}f_o$=3,800, $\tau_f$=+135), $TiO_2$-50vol%ZBS($\varepsilon_{r}$=36.4, $Q{\times}f_o$= 7,500, $\tau_f$=+159), $TiO_2$-50vol%BBS($\varepsilon_{r}$=56.4, $Q{\times}f_o$=520, $\tau_f$=+119)을 나타내었다. 따라서 LTCC용 기판재료 및 마이크로파 유전체로 응용이 가능한 것으로 확인되었다.