• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.838-841
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• 2004

[ $B_2O_3$ ] added $Ba(Mg_{1/3}Nb_{2/3})O_3$ (BBMN) ceramics were not sintered below $900^{\circ}C$. However, when CuO was added to the BBMN ceramic, it was sintered even at $850^{\circ}C$. The amount of the $Ba_2B_2O_5$ second phase decreased with the addition of CuO. Therefore, the CuO additive is considered to react with the $B_2O_3$ inhibiting the reaction between $B_2O_3$ and BaO. Moreover, it is suggested that the solid solution of CuO and $B_2O_3$ might be responsible for the decrease of the sintering temperature of the specimens. A dense microstructure without pores was developed with the addition of a small amount of CuO. However, a porous microstructure with large pores was formed when a large amount of CuO was added. The bulk density the dielectric constant $({\varepsilon}_r)$ and the Q-value increased with the addition of CuO but they decreased when a large amount of CuO was added. The variations of those properties are closely related to the variation of the microstructure. The excellent microwave dielectric properties of Qxf=21500 GHz, ${\varepsilon}_r=31$ and temperature coefficient of resonance frequency$({\tau}_f)=21.3\;ppm/^{\circ}C$ were obtained for the $Ba(Mg_{1/3}Nb_{2/3})O_3+2.0\;mol%B_2O_3+10.0$ mol%CuO ceramic sintered at $875^{\circ}C$ for 2h.

• 한국재료학회지
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• 제11권7호
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• pp.562-568
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• 2001

60ZnO-20B$_2$O$_3$-10SiO$_2$-10PbO의 조성을 가진 결정성 봉착용 유리분말과 ZrB$_2$분말을 출발물질로 사용하여 Na분위기 하에서 소결한 복합소결체를 저항체 후막으로써 사용가능성을 검토하였다. 도전성입자 ZrB$_2$는 소결중 매우 민감한 산화특성을 나타내었으며, 이것은 로내 또는 시편내에 잔류된 미량의 산소 및 유리성분 중 B$_2$O$_3$의 반응에 의한 배위수 변화과정에서 유리되는 산소가 원인으로 될 수 있다는 것을 시편의 밀도 및 부피변화 등을 통해 확인되었다. 각 혼합물의 소결온도와 혼합비 변화에 따라 내부조직의 변화와 함께 10~$10^{5}{\Omega}/cm^2$정도의 제어 가능한 저항값을 얻을 수 있었다. 이러한 결과들로부터 유리기지 중에서 ZrB$_2$입자들의 치밀화 경향을 갖는 복합소성시편들에 대한 거시적인 관점에서 도전성경로형성 및 도전기구를 설명하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 추계학술대회 논문집
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• pp.68-72
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• 1997

In this paper, to obtain the YbB $a_2$C $u_3$ $O_{x}$ superconductor, the mixed Powders of Y $b_2$ $O_3$, BaC $O_3$, CuO and Y $b_2$BaCu $O_{5}$, BaCu $O_2$ were used and the various calcining conditions were applied for the 123 phase of YbB $a_2$C $u_3$ $O_{x}$. Samples were prepared by the mixed oxide method and calcined with various temperatures of 88$0^{\circ}C$ ~91$0^{\circ}C$ . It was observed that the distribution of YbB $a_2$C $u_3$ $O_{x}$ phase which was calcined at 90$0^{\circ}C$ for 12 hours and 99 hours. But the result of long time calcination(99 hrs), the 123 phase of YbB $a_2$C $u_3$ $O_{x}$ was existed between 89$0^{\circ}C$ and 91$0^{\circ}C$ . And the best case could be obtained at the calcination temp. of 90$0^{\circ}C$ from the mixed Powder of YbB $a_2$C $u_3$ $O_{5}$ and Bacu $O_2$ which were prepared individually.idually.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.563-566
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• 2000

The effect of CuO and CuO-B $i_2$ $O_3$ additives on microwave dielectric properties of (P $b_{0.45}$C $a_{0.55}$)[F $e_{0.5}$N $b_{0.5}$)$_{0.9}$S $n_{0.1}$] $O_3$were investigated to decrease the sintering temperature for usage of Low Temperature Co-firing Ceramics (LTCC). The (P $b_{0.45}$C $a_{0.55}$)[F $e_{0.5}$N $b_{0.5}$)$_{0.9}$S $n_{0.1}$] $O_3$ceramics was sintered at 11$65^{\circ}C$. In order to decrease the sintering temperature, CuO and Cuo-B $i_2$ $O_3$ were added in the (Pb,Ca)[(Fe,Nb)Sn] $O_3$ with CuO-B $i_2$ $O_3$. For the addition of 0.4 wt.% CuO, the sintered density and the dielectric constant of the ceramics were revealed the maximum values of the 6.06g/c $m^2$ and 83 respectively and temperature coefficient of resonance frequency ($\tau$$_{f}$) shifted to the positive value. As increasing B $i_2$ $O_3$to the (Pb,Ca)[(Fe,Nb)Sn] $O_3$ with CuO-B $i_2$ $O_3$with 0.2 wt.% CuO, the sintered density, the $\varepsilon$$_{r}$ and the Q was decreased, and $\tau$$_{f}$ was minimized at 0.2 wt.% CuO, and 0.2 wt.% B $i_2$ $O_3$. For this composition, dielectric properties were $\varepsilon$$_{r}$ of 81, Q. $f_{0}$ of 4400 GHz, and $\tau$$_{f}$ of 5 ppm/$^{\circ}C$ at sintering temperature of 100$0^{\circ}C$. the relationship between the microstructure and properties of ceramics was studied by X-ray diffraction(XRD), scanning electron microscopy(SEM).copy(SEM).oscopy(SEM).copy(SEM).EM).

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2003년도 춘계학술발표논문집
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• pp.87-90
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• 2003

B₂O₃침가에 따른 (Zn/sub 0.8.Mg/sub 0.2/)TiO₃계 세라믹스의 마이크로파 유전특성에 대하여 연구하였다. B₂O₃의 침가량에 비례하여 B₂O₃와 (Zn/sub 0.8.Mg/sub 0.2/)TiO₃와외 반응에 의한 TiO₂ 석출물의 양이 증가하며 공진주파수 온도계수가 증가하였다. 소결온도에 따라 액상의 양, 미세조직, TiO₂와 2차상의 석출거동이 상이하게 나타났다. 6.19mo1.％ B₂O₃물 첨가한 시편을 900℃에서 5시간 소결시 ε/sub r/ = 23.5, Q×f/sub o/ = 67,500 ㎓, T/sub f/ = -1.42 ppm/℃의 우수한 마이크로파 유전특성을 얻을 수 있었다.

• 한국세라믹학회지
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• 제35권12호
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• pp.1274-1279
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• 1998

The glass forming ability of the PbO-B2O3-TiO3-BaO system was investigated in relation to transitieon tem-peratures and the atomic ratio between constituents. Glass forming tendency was improved as the tem-peratures and the atomic ratio between constituents. Glass forming tendency was improved as the tem-perature differences between liquidus temperature and crystallization(or glass transition) temperature de-creased and the temperature difference between crystallization and glass transition temperature increases. The atomic ratio could be used as a criterion to deign glass systems. The interposition of B and Ba atoms between Pb and Ti atoms was one of important factors in glass formation.

• Bulletin of the Korean Chemical Society
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• 제14권2호
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• pp.188-191
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• 1993

The reaction between methyl 2,3-di-O-benzyl-4,6-di-O-mesyl-${\alpha}$-D-glucopyranoside (1b) and potassium superoxide resulted in hydrolysis, and gave methyl 2,3-di-O-benzyl-${\alpha}$-D-glucopyranoside (1) as a sole product. When the reaction was performed with a vicinal dimesylate, methyl 4,6-O-benzylidene-2,3-di-O-mesyl-${\alpha}$-D-altropyranoside (4b), again the hydrolysis product, methyl 4,6-O-benzylidene-${\alpha}$-D-altropyranoside (4) was obtained. However, the reaction of potassium superoxide with another vicinal dimesylate, methyl 4,6-O-benzylidene-2,3-di-O-mesyl-${\alpha}$-D-glucopyranoside (3b), nucleophilic displacement took place to afford methyl 4,6-O-benzylidene-${\alpha}$-D-altropyranoside (4). Apparently different results from two trans vicinal dimesylates, 3b and 4b are explained by the transient formation of epoxides, methyl 2,3-anhydro-4,6-O-benzylidene-${\alpha}$-D-allopyranoside (8) and methyl 2,3-anhydro-4,6-O-benzylidene-${\alpha}$-D-mannopyranoside (9) by $KO_2$. The reaction between the allo epoxide 8 and $KO_2$ gave altro 4. The manno epoxide 9 also afforded altro 4 as the major product. Facile epoxide formation by the reaction of a vicinal dimesylate and superoxide was also observed with 3-O-benzyl-1,2-O-isopropylidene-5,6-di-O-mesyl-${\alpha}$-D-glucofuranose: 5,6-anhydro-3-O-benzyl-1,2-O-isopropylidene-${\beta}$-L-idofuranose was obtained.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.33-33
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• 2007

In PDP industry, the dielectrics and barrier ribs have been required with low dielectric constant, low melting point and Pb-free composition due to the low power consumption, low signal delay time and the environment restriction. We were studied with $B_2O_3-Al_2O_3$-SrO glass systems about optical, thermal and dielectric properties. The glass forming region of the $B_2O_3-Al_2O_3$-SrO glass systems was narrow due to the amount of the glass former $(B_2O_3)$. The glass transition temperature (Tg) of the glasses was at $550{\sim}590^{\circ}C$. The glasses have 6~8 for the dielectric constant. Furthermore, the transmittance of the glasses was over 80% on the range of the visible ray. From the results, the glasses of the $B_2O_3-Al_2O_3$-SrO glass systems should enable to be a good candidate of the PDP devices for information display with low dielectric constant. The aim of this study is to give a fundamental result of new glass system for low dielectric constant in the information display.

• 전자공학회논문지 IE
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• 제43권4호
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• pp.8-12
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• 2006

본 논문에서는 $SiO_2-ZnO-B_2O_3$ 계 및 $P_2O_5$-ZnO-BaO 계의 반사율과 유전특성을 $TiO_2$의 양에 따라 조사하였다. 반사율은 $TiO_2$ 함량이 증가함에 따랴 감소하였다 여기서 $P_2O_5$-ZnO-BaO계는 $SiO_2-ZnO-B_2O_3$ 계보다 더 낮은 반사율을 나타내었으며, 유전상수는 $P_2O_5$-ZnO-BaO 계가 $SiO_2-ZnO-B_2O_3$ 계보다 높았다. 두 계 모두 유전상수는 $TiO_2$의 양에 따라 증가하는 특성을 보였다. 이 결과는 높은 반사율과 항복특성이 요구되는 PDP디스플레이의 후면 유전층에 적용할 수 있을 것으로 생각된다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.677-680
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• 2003

The effect of $B_2O_3$ addition on the sintering behavior and microwave dielectric properties of $(Zn_{0.8}Mg_{0.2})TiO_3$ ceramic system were investigated. Highly dense samples were obtained at the sintering temperatures below $900^{\circ}C$. Temperature coefficient of resonance frequency(${\tau}_f$) changes to a positive value with increasing the amount of $B_2O_3$ because of the increased amount of rutile phase. The $Q{\times}f_o$ values were determined by the microstructures and sintering shrinkages which are affected by the rutile or second phase. When 6.19 mol.% of $B_2O_3$ added and sintered at $900^{\circ}C$ for 5h, it exhibits ${\epsilon}_r$ =23.5, $Q{\times}f_o$= 67,500 GHz, and ${\tau}f=-1.42ppm/^{\circ}C$.