• 한국재료학회지
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• 제24권12호
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• pp.710-714
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• 2014

The effect of titanium dioxide ($TiO_2$) on the properties of color conversion glasses was examined for glasses based on $BaO-ZnO-B_2O_3-SiO_2$. One glass sample, containing 25 mol% of each component, was used as a reference; the other three glass samples contained 1, 3, and 5 mol% $TiO_2$, respectively. The four color conversion glass samples were prepared by sintering a mixture of glass frits and a $YAG:Ce^+$ phosphor. The characteristics of the color conversion glass samples, such as luminous efficacy, luminance, CIE (Commission International de I'Eclairage) chromaticity, CCT (Correlated Color Temperature), and CRI (Color Rendering Index) were analyzed according to the PL spectrum. The refractive index of the glass samples was found to increase with the titanium dioxide content. In conclusion, luminous efficacy of color conversion glasses increased as the content of $TiO_2$ was raised in the glass matrix.

• 한국재료학회지
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• 제33권10호
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• pp.414-421
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• 2023

Infrared radiation (IR) refers to the region of the electromagnetic radiation spectrum where wavelengths range from about 700 nm to 1 mm. Any object with a temperature above absolute zero (0 K) radiates in the infrared region, and a material that transmits radiant energy in the range of 0.74 to 1.4 um is referred to as a near-infrared optical material. Germanate-based glass is attracting attention as a glass material for infrared optical lenses because of its simple manufacturing process. With the recent development of the glass molding press (GMP) process, thermal imaging cameras using oxide-based infrared lenses can be easily mass-produced, expanding their uses. To improve the mechanical and optical properties of commercial materials consisting of ternary systems, germanate-based heavy metal oxide glasses were prepared using a melt-cooling method. The fabricated samples were evaluated for thermal, structural, and optical properties using DSC, XRD, and XRF, respectively. To derive a composition with high glass stability for lens applications, ZnO and Sb₂O₃ were substituted at 0, 1, 2, 3, and 4 mol%. The glass with 1 mol% added Sb₂O₃ was confirmed to have the optimal conditions, with an optical transmittance of 80 % or more, a glass transition temperature of 660 ℃, a refractive index of 1.810, and a Vickers hardness of 558. The possibility of its application as an alternative infrared lens material to existing commercial materials capable of GMP processing was confirmed.

• 헤리티지:역사와 과학
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• 제36권
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• pp.241-266
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• 2003

Glass pieces excavated from Mireuksa Temple dated $7^{th}$ century A.D. were characterized by chemical composition, specific gravity and melting point. Lead isotope ratios of lead glasses were also compared with those of lead ore to attribute which lead ore was delivered for making lead glass. It was known that some lead glasses found in Japan were similar with those of Mireuksa Temple as comparing the data of chemical composition and lead isotope ratios. Characteristics of lead glass from Mireuksa Temple Thirty five glass pieces of Mireuksa Temple were analyzed for five oxides and found that all was lead glass system(PbO-$SiO_2$) with the range of 70~79% for PbO and 20~28% for $SiO_2$. The concentrations of oxides such as $Al_2O_3$, $Fe_2O_3$ and CuO were below 0.4%, 0.3% and 0.9%, respectively. Principal component analysis(PCA) as a statistical method was carried out to classify glasses with the similarities of chemical concentrations. The result of PCA has shown that three groups of glasses were created according to the excavation positions and two major oxides(PbO and $SiO_2$) greatly contributed to the dispersion of glasses on principal component 1(PC1) axis and trace element oxides($Al_2O_3$ and $Fe_2O_3$) for PC2 axis. Most of lead glasses were greenish by the efficacy of iron and copper oxides and some showed yellowish-green. The gravity of lead glasses was about 4.4~5.4 and estimated melting point was near $670^{\circ}C$. Lead isotope ratios of glasses were analyzed and found quite close to a lead ore from the Bupyeong mine in Gyeonggi-do. Comparison with lead glasses found in Japan Lead glasses of Mireuksa Temple were compared with those of Japan on the basis of chemical and physical data. Chemical compositions of Japanese lead glasses dated $7^{th}{\sim}8^{th}$ century A.D. were nearly similar with those of Mireuksa Temple but lead isotope ratios of those were separated into two groups. Three distribution maps of lead ores of Korea, Japan and China with lead isotope ratios were applied for lead glasses found in Japan. The result have shown that the locations of lead glasses from Fukuoka Prefecture coincided with the region of northen part of Korea and similar with those of Mireuksa Temple and lead glasses from Nara Prefecture dated $8^{th}$ century A.D. were located in the region of Japanese lead ore. This research has demonstrated that lead glasses of Mireuksa Temple conveyed to Miyajidake site, Fukuoka Prefecture around $7^{th}$ century A.D. and glass melting pots and glass beads excavated from Nara Prefecture confirmed the first use of Japanese lead ore for production of lead glasses from the end of $7^{th}$ century A.D.

• Current Photovoltaic Research
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• 제2권1호
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• pp.14-17
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• 2014

In this paper, indium reduced materials for transparent conductive electrodes (TCE) were fabricated and their physical properties were evaluated. Two of materials, indium-zinc-tin oxide (IZTO) and aluminum (Al) were selected as TCE materials. In case of IZTO nanoparticles, composition ratios of In, Zn and Sn is 8:1:1 were synthesized. Size of the synthesized IZTO nanoparticles were less than 10 nm, and specific surface areas were about $90m^2/g$ indicating particle sizes are very fine. Also, the IZTO nanoparticles were well crystallized with (222) preferred orientation despite it was synthesized at the lowered temperature of $300^{\circ}C$. Composition ratios of In, Zn and Sn were very uniform in accordance with those as designed. Meanwhile, Al was deposited onto glass by sputtering in a vacuum chamber for mesh architecture. The Al was well deposited onto the glass, and no pore was observed from the Al surface. The sheet resistance of Al on glass was about $0.3{\Omega}/{\square}$ with small deviation of $0.025{\Omega}/{\square}$, and adhesion was good on the glass substrate since no pelt-off part of Al was observed by tape test. If the Al mesh is combined with ink coated layer which is consistent of IZTO nanoparticles, it is expected that the good and reliable metal mesh architecture for TCE will be formed.

• 한국세라믹학회지
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• 제22권3호
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• pp.35-40
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• 1985

The composition of the base glass was determined to be $Na_2O$ 15, $Fe_2O_3$ 35, $B_2O_3$ 0~20, $P_2O_5$ 30~50 by mole percent. The heating temperature for nucleation was determined by means of thermal expansion curve. Crystalline phases were investigated by X-ray diffraction method and I.R Spectra. Electrical conductivities of glass spec-imens were observed in the temperature range 25~20$0^{\circ}C$ The activation energies of these specimens were caculated. The results obtained were as follows : 1) The limit composition of the melts 15mol% $Na_2O$ 35mole% $Fe_2O_5$ 20mole% $B_2O_3$ 30mole% $P_2O_5$ was able to be formed into desired shapes during cooling, . 2) In the measurement of d. c conductivity($\delta$) on the glasses in the system $15Na_2O-35Fe_2O_3$-$B_2O_3$-(50-x) $P_2O_5$ the values decreased by replacing 5 mole% $P_2O_5$ with $B_2O_3$ 3) The d. c conducties of heat treated samples were increased by replacing $P_2O_5$ with $B_2O_3$ 4) $B_2O_3$ contributed to precipitate crystals such as${\gamma}$-$Fe_2O_3$ $Fe_3O_4$ which had the advantage of electronic conduction in heat treated samples. 5) The slope plotted Log($\delta$) versus 1/T in this glass system was linear in the measured temperature range.

• 한국표면공학회지
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• 제48권6호
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• pp.322-328
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• 2015

We investigated the diffusion behaviors, electrical properties, microstructures, and composition of In-Ga-Zn-O (IGZO) oxide thin films deposited by radio frequency reactive magnetron sputtering with increasing annealing temperatures. The samples were deposited at room temperature and then annealed at 300, 400, 500, 600 and $700^{\circ}C$ in air ambient for 2 h. According to the results of time-of-flight secondary ion mass spectrometry and X-ray photoelectron spectroscopy, no diffusion of In, Ga, and Zn components were observed at 300, 400, 500, $600^{\circ}C$, but there was a diffusion at $700^{\circ}C$. However, for the sample annealed at $700^{\circ}C$, considerable diffusion occurred. Especially, the concentration of In and Ga components were similar at the IGZO thin film but were decreased near the interface between the IGZO and glass substrate, while the concentration of Zn was decreased at the IGZO thin film and some Zn were partially diffused into the glass substrate. The high-resolution transmission electron microscopy results showed that a phase change at the interface between IGZO film and glass substrate began to occur at $500^{\circ}C$ and an unidentified crystalline phase was observed at the interface between IGZO film and glass substrate due to a rapid change in composition of In, Ga and Zn at $700^{\circ}C$. The best values of electron mobility of $15.5cm^2/V{\cdot}s$ and resistivity of $0.21{\Omega}cm$ were obtained from the sample annealed at $600^{\circ}C$.

• 한국전기전자재료학회논문지
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• 제21권5호
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• pp.440-446
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• 2008

To manufacture the MLCC with X7R for high voltage stability, $BaTiO_3-MgO-MnO_2-Y_2O_3$ with $(Ba_{0.4}Ca_{0.6})SiO_3$ glass frit was formulated. Based on this composition, the addition of $Er_2O_3$ showed that TCC(Temperature Coefficient Capacitance) at $85^{\circ}C$ was improved from 5 % to ${\sim}0\;%$, but the dielectric constant and IR (Insulation Resistance) were decreased. The glass frit improved the dielectric constant and IR, so the appropriate contents of $Er_2O_3$ and glass frit were 0.6 mol% and 1 wt%, respectively. It showed that the dielectric constant and RC constant were 2,550 and 2,000 (${\Omega}F$), respectively in the sintering condition at $1250^{\circ}C$ in PO2 $10^{-7}$ Mpa. The MLCC with $3.2{\times}1.6$ (mm) size and $1\;{\mu}F$ was also suited for X7R with the above composition.

• 분석과학
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• 제26권3호
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• pp.205-210
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• 2013

졸-겔법에 의한 LAS계 결정화 유리합성공정에서 출발물질로 사용된 금속 알콕사이드의 조성비, 조핵제의 첨가량 및 열처리조건이 생성된 유리의 결정화 특성에 미치는 영향을 조사하였다. LAS 유리전구체의 겔화시간은 $TiO_2$의 첨가량이 늘어남에 비례하였고, 금속 알콕사이드 중의 TEOS의 몰비가 증가함에 따라서 폭발적으로 증가하였다. 또한 TEOS의 조성비가 커지면 LAS계 유리의 결정화 온도는 증가 하였지만, $TiO_2$ 첨가량의 영향은 미미하였다. 그리고 $TiO_2$의 첨가량이 늘어나면 낮은 온도에서도 결정성이 증가하는 것으로 나타나 이는 조핵제가 LAS계 결정화 유리의 결정성을 향상시키는 것으로 판단되었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.284-284
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• 2007

In this study, the microwave dielectric property variations of (1-x)$BiNbO_4-(x)ZnNb_2O_6$ composites (x=0.3, 0.5 and 0.7) with 10wt% zinc borosilicate(ZBS) glass was investigated as a function of the substitution of $ZnNb_2O_6$ with a view to applying thes system to LTCC technology. The all composition addition of 10wt% ZBS glass ensured a successful sintering below $900^{\circ}C$. In addition, a small amount of $Bi_2SiO_5$ as the secondary phase was observed in the all composition. The substitution of $ZnNb_2O_6$ on the $BiNbO_4$ composites increased the $Q{\times}f$ values, but it decreased the sinterability and dielectric constant due to the high sintering temperature and low dielectric constant of $ZnNb_2O_6\;than\;BiNbO_4$ ceramics. The increasing of $ZnNb_2O_6$ content from 0.3 to 0.7 in the (1-x)$BiNbO_4-(x)ZnNb_2O_6$ composites with 10wt% ZBS glass sintered at $900^{\circ}C$ demonstrated 28.1~15.6 in the dielectric constant$({\varepsilon}_r)$, 5,500~8,700GHz in the $Q{\times}f$ value.

• 한국결정성장학회지
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• 제24권3호
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• pp.120-126
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• 2014

LED 조명등의 내구성 문제를 개선할 목적으로 폴리카보네이트 광확산판 소재를 대체하기 위한 반투명 녹색 컬러유백유리를 제조하였다. 녹색 컬러유백유리의 원료로는 유백제로서 인산칼슘을, 착색제로서 산화철을 사용하였고, $1550^{\circ}C$에서 용융하였다. 그 결과로서 LED 조명등의 광확산판으로서 90 % 이상의 높은 헤이즈 값과 1 %의 낮은 평행광 투과율을 가짐에 따라 직사광에 의한 눈부심이 없어 일반 컬러유리에 비해 매우 우수한 광학특성을 나타내는 반투명의 녹색 컬러유백유리가 얻어졌다. 따라서 녹색 컬러유백유리가 높은 열저항성과 내구성을 가지고 폴리카보네이트 광확산판을 대체하기 위한 LED 조명등의 광확산판 소재로 사용될 수 있을 것으로 판단되었다.