• Journal of the Korean Society of Safety
• /
• v.20 no.4 s.72
• /
• pp.29-33
• /
• 2005

In this paper, reflectance and the dielectric characteristics for $P_2O_5-ZnO-BaO$ system and $SiO_2-ZnO-B_2O_3$ system have been investigated as a function of contents of $TiO_2$. The reflectance was decreased with increasing the contents of $TiO_2$ and the reflectance of $P_2O_5-ZnO-BaO$ system was lowered than that of $SiO_2-ZnO-B_2O_3$ system. The dielectric constant of $P_2O_5-ZnO-BaO$ system was higher than $SiO_2-ZnO-B_2O_3$ system, and the dielectric constant in the both system was increased with increasing of $TiO_2$ contents. This can be explained as the space charge effects. These results are could be applied to the under plate dielectrics of PDP required high reflective ratio and breakdown strength.

• The Korean Journal of Ceramics
• /
• v.4 no.3
• /
• pp.207-212
• /
• 1998

By comparison of the experimental results in two systems of ZnO varistors, it's appear that Sb2O3 is the indispensable element for twining in ZnO varistors and the Zn7Sb2O12 spinel acts as the nucleus to form twins. Al2O3 is not the origin of twining in ZnO varistor, but it was found that Al2O3 could strengthen the twining and form a deformation twining by ZnAl2O4 dragging and pinning effect. The inhibition ratios of grain and nonuniformity of two systems ZnO varistors increase with the increase of Al2O3 content. The twins affect the inhibition of grain growth, the mechanism could be explained follow as: twins increase the mobility viscosity of ZrO grain and grain boundary, and drag ZrO grain and liquid grain boundary during the sintering, then the grain growth is inhibited and the microstructure becomes more uniform.

• Journal of the Korean Ceramic Society
• /
• v.28 no.2
• /
• pp.160-166
• /
• 1991

Microstructure and phase changes during the sintering of ZnO varistors were studied in ZnO-Bi2O3-CoO-Sb2O3 and ZnO-Bi2O3-CoO-Sb2O3-Cr2O3 systems using acanning electron microscopy (SEM) with an energy dispersive X-ray analysis (EDAX), X-ray diffraction (XRD) and differential thermal analysis (DTA). The spinel phase and the Bi2O3 phase were formed by the decomposition of the pyrochlore phase during heating. The spinel particles (2-4$\mu\textrm{m}$), which were formed both along ther grain boundaries and within the ZnO grain, were always found near the pyrochlore phase. Intergranular phases (Bi2O3 and pyrochlore) were precipitated from the liquid phase during cooling. The Bi2O3 phases were located at the triple (or multiple) point of the ZnO grains. Cr2O3 played a role in decreasing the formation temperature of the spinel phase and Bi2O3 phase during sintering, and inhibited the grain growth.

• Journal of the Korean Chemical Society
• /
• v.39 no.3
• /
• pp.176-185
• /
• 1995

To improve photosensisitizing efficiency of ZnO/$H_2Pc(I)_x$ system, ZnO/$H_2Pc(I)_x$ system was dispersed in a typical photoconductive polymer of poly(9-vinylcarbazole)(PVCZ). The iodine dopant level(x) of ZnO/${\chi}-H_2Pc(I)_x$ is proportional to concentration of iodine, whereas x of ZnO/${\beta}-H_2Pc(I)_x$ decreased from the highest x=0.97 at more than $6.3{\times}10^{-3}$ M iodine solution. The Raman spectra of ZnO/${\chi}-H_2Pc(I)_x$ at 514 nm exhibited characteristic $I_3^-$ patterns in the range of 50∼550 $cm^{-1}$ at $x{\geq}0.57.$ The surface photovoltage of ZnO/${\chi}-H_2Pc(I)_{0.48}$/PVCZ was approximately 1.6 times greater than ZnO/${\chi}-H_2 Pc(I)_{0.48}$ and was 1.8 times of ZnO/${\chi}-H_2Pc(I)_{0.57}$/PVCZ at 670 nm. With ZnO/$H_2Pc(I)_x$/PVCZ, the highest iodine dopant levels showed a higher photovoltage. Therefore the injection of holes from H2Pc into PVCZ resulted in that photosensisitizing effect of ZnO/$H_2Pc(I)_x$/PVCZ system was improved compared to ZnO/$H_2Pc(I)_x$ case.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.11a
• /
• pp.245-245
• /
• 2007

본 연구는 $Bi_2O_3$, ZnO 및 $Nb_2O_5$로 이루어진 두 가지의 $Bi_2(Zn_{1/3}Nb_{2/3})_2O_7$와 $(Bi_{1.5}Zn_{0.5})(Zn_{0.5}Nb_{1.5})O_7$ pyrochlore를 제조한 후, ZBS 및 BZBS 유리를 각각 첨가하여 저온 소결 및 마이크로파 유전 특성을 고찰하였다. 두 가지의 pyrochlore에 대하여 하소 온도에 따른 상 합성 유무를 고찰한 결과 $900^{\circ}C$에서 단일 상을 갖는 pyrochlore를 제조할 수 있었다. 두 가지의 pyrochlore에 ZnO-rich ZBS 유리와 $Bi_2O_3$-rich BZBS 유리를 3, 5 wt%로 첨가한 후 $800{\sim}950^{\circ}C$에서 소결한 결과 ZBS 및 BZBS 유리를 5wt%를 첨가하였을 때 $900^{\circ}C$에서 소결이 가능하였다. 또한 마이크로파 유전 특성을 고찰한 결과, $(Bi_{1.5}Zn_{0.5})(Zn_{0.5}Nb_{1.5})O_7$의 pyrochlore는 고주파에서 유전 특성 측정이 되지 않았다. $Bi_2(Zn_{1/3}Nb_{2/3})_2O_7$의 pyrochlore의 경우 5 wt% ZBS 및 BZBS 유리를 첨가하여 $900^{\circ}C$에서 소결한 시편의 마이크로파 유전 특성은 ${\varepsilon}_r$= 62.8~68.3, $Q{\times}f$ value= 3,500~2,700 GHz을 나타내었다.

• Journal of the Korean Vacuum Society
• /
• v.10 no.2
• /
• pp.213-218
• /
• 2001

ZnO and ZnO:In films were deposited on the glass substrates by a spray pyrolysis method. It is found that ZnO films were polycrystalline with the preferred orientation (002) and have a hexagonal structure with lattice constants of a=3.242 $\AA$ and c=5.237 $\AA$. The crystalline structure of ZnO:In films deposited at the In content of 0~6.03 at. % were the same as that of ZnO films, but its lattice constants was slightly larger than those of ZnO films. The relative atomic ratios of metal ion of ZnO:In films were in accordance with those of the spray solution within the experimental error. The minimum resistivity of and the maximum carrier concentration of 19.1 $\Omega\cdot\textrm{cm}$ and the maximum carrier concentration of $2.11\times10^{19}\textrm{cm}^{-3]$ obtained from the ZnO:In films when In content was 2.76 at. %. The optical transmission of the sample grown at the In content of 3.93 at. % was about 95% in the wavelength between 400 and 800 nm.

• Journal of the Korean Ceramic Society
• /
• v.50 no.1
• /
• pp.57-62
• /
• 2013

We investigated the thermal and electrical properties of the $B_2O_3-ZnO-Bi_2O_3$ glass system as a sealing material in sheath heater modules. A composition with over 90 wt% $Bi_2O_3$ in the $B_2O_3-ZnO-Bi_2O_3$ system was glassified by controlling the cooling rate. The glass transition temperature and thermal expansion coefficient in bismate glass could be controlled by the minor ingredients of ZnO, $SiO_2$, $BaO_2$, and $K_2O$. The $B_2O_3-ZnO-Bi_2O_3$ glass system bonded well to metal, and bismate glass insulating properties were comparable to those of bismate glass $B_2O_3-ZnO-PbO$ glass system in a sheath heater module.

• Journal of the Korean Ceramic Society
• /
• v.31 no.11
• /
• pp.1396-1400
• /
• 1994

Electrical properties in the ZnO-Bi2O3-CoO-Zn7Sb2O12 system were investigated with Zn7Sb2O12 content (0.1~2 mol%). The increase of the Zn7Sb2O12 content inhibited the grain growth of ZnO, which showed a narrow grain size distribution of ZnO. The breakdown voltage (Vb) increased markedly with 1 mol% Zn7Sb2O12 addition due to the grain growth control behaviour of the Zn7Sb2O12 . The nonlinear I-V characteristic was significantly influenced by the Zn7Sb2O12 content (or Bi2O3/Zn7Sb2O12 ratio). Addition of 0.5 mol% Zn7Sb2O12 showed the highest nonlinear coefficient ($\alpha$) of 43. The leakage current in prebreakdown region was decreased with increasing Zn7Sb2O12 content.

• Journal of the Korean Magnetics Society
• /
• v.12 no.5
• /
• pp.195-200
• /
• 2002

Low temperature sintering of Co$_2$Z type Ba ferrites with various oxide additives has been studied. Co$_2$Z phase was obtained by 2 step calcination and XRD peaks showed a good agreement with the peaks of the standard Co$_2$Z phase, except for some minor extra peaks. ZnO-B$_2$O$_3$ glass, ZnO-B$_2$O$_3$ and CuO, ZnO-B$_2$O$_3$ and Bi$_2$O$_3$, and ZnO-Bi$_2$O$_3$ glass were added to lower sintering temperatures. Specimens were sintered at the temperature range between 900 $^{\circ}C$ and 1000 $^{\circ}C$. In the single addition of ZnO-B$_2$O$_3$ glass, the specimen with 7.5 wt％ showed the highest shrinkage. Specimens with complex addition of ZnO-B$_2$O$_3$ glass with CuO or Bi$_2$O$_3$ showed higher shrinkages and initial permeabilities than single addition of ZnO-B$_2$O$_3$ glass. Shrinkages and initial permeabilities of the specimens with ZnO-Bi$_2$O$_3$ glass were higher than those of ZnO-B$_2$O$_3$ glass addition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.07a
• /
• pp.1057-1060
• /
• 2001

By comparison of the experimental results in two systems of ZnO varistors, its appear that Sb$_2$O$_3$is the indispensable element for twinning in ZnO varistors, and the Zn$_{7}$Sb$_2$O$_{12}$ spinel acts as the nucleus to form twins. A1$_2$O$_3$is not the origin of twinning in ZnO varistor, but it was found that A1$_2$O$_3$could strengthen the twinning and form a deformation twinning by ZnA$_{12}$O$_4$-dragging and pinning effect. The inhibition ratios of grain growth and nonuniformity of two systems ZnO varistors increase with the increase of A1$_2$O$_3$content. The twins affect the inhibition of grain growth, the mechanism could be explained follow as : twins increase the mobility viscosity of ZnO grain and grain boundary, and drag ZnO grain and liquid grain boundary during the sintering, then the grain growth is inhibited, and the microstructure becomes more uniform.orm.m.