• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2005.07a
• /
• pp.453-454
• /
• 2005

PDP에 사용되는 유전체, 격벽재, 봉착재 등의 glass들은 모두 PbO를 다량 함유하는 저융점 유리조성계로 되어있다. 최근 환경규제에 따라 Pb 대체 재료의 개발이 필요하게 되었으며, 그에 대한 많은 연구들이 진행되고 있다. 본 연구에서는 투명 유전체를 겨냥한 저융점 이면서 무해한 3성분계 Pb-free 유리를 제조하였다. 또한 SnO 계 유리와의 혼합 용융에 의한 영향을 고찰하였으며, 유리로서의 고유물성과 응용용도별 특성을 함께 고찰하였다.

• Journal of the Korean Ceramic Society
• /
• v.16 no.2
• /
• pp.83-88
• /
• 1979

The Anorthite is useful compound for some ceramic industries but it is difficult to produce Anorthite because of its high melting point (1553$^{\circ}C$) and narrow firing range. On this study, glass frit was added to Anorthite batch composition to widen firing range and lower melting point. After mixing a glass frit $(Na_2O-CaO-6SiO_2)$ with Anorthite, it was melted and quenched. Ratio of Anorthite vs. glass frit was 9 : 1, 8.5 : 1.5, 8 : 2, 7.5 : 2.5, 7 : 3. In those batch composition added amount of $No_2O$ were between 1.3wt.% and 3.9wt.%. To find the thermal change of the quenched, D.T.A. was surveyed. The quenched were fired at various vitrification temperature and detected by X-Raydiffraction analysis. With addition of glass frit, firing range and vitrification temperature of Anorthite was 100~15$0^{\circ}C$ and 1050~115$0^{\circ}C$ respectively. Optimum amount of glass frit was 20wt.% for the upper mentioned.

• Journal of the Microelectronics and Packaging Society
• /
• v.6 no.4
• /
• pp.55-59
• /
• 1999

One of lead free glass, Bi based solder glass is investigated for electronic packaging application. The melting temperature of glass about $550^{\circ}C$ at Bi based glass (70wt% $B_2O_3$ + l5wt%$B_2O_3$ + 8wt% $SiO_2$ + 2wt% $P_2O_5$ + 4wt% $A1_2O_3$ +lwt% ZnO) and varied with $P_2O_5$ content in this system. Crystallized glasses were obtainded after 1hr heat teratment at $450^{\circ}C$ with 10wt% of $P_2O_5$ addition. Much higher melting temperature was observed at $B_2O_3$ rich composition area.

• IE interfaces
• /
• v.13 no.1
• /
• pp.78-91
• /
• 2000

This paper presents a computerized quality forecasting system for glass manufacturing. In forecasting the molten glass quality, we are concerned with three major issues : (1) to find the reasonable time lags between a set of process conditions and the quality measurement of glass products, (2) to find the most significant process variables affecting the quality, and (3) to construct the appropriate causal forecasting models using genetic algorithms. The experimental results show the proposed model results in better forecasting than linear regression model. The suggested forecasting model was implemented successfully and is being currently used in a real manufacturing line.

• Journal of Intelligence and Information Systems
• /
• v.8 no.1
• /
• pp.63-74
• /
• 2002

This paper presents an application result of on-line fault diagnosis system for glass melting furnace using a fuzzy expert system. Operators maintain the furnace using the furnace Knowledge and experience, which directly influence the furnace and glass product. Firstly, knowledge and experience is achieved and analyzed to implement the furnace Knowledge and experience into fuzzy expert system. The acquired Knowledges determined as a crisp rule or a fuzzy rule to expect its characteristics. And, a linear regression is used as the input of fuzzy rule to consider the exact knowledge of human operator. The fuzzy expert system is implemented with G2 which is an on-line expert system tool of Gensym Co. The application to a production furnace of Samsung-Corning Co. in Suwon shows successful results of proposed fuzzy expert system.

• Journal of the Korean Ceramic Society
• /
• v.40 no.11
• /
• pp.1127-1131
• /
• 2003

Phosphate glasses known for low melting temperature glasses in electrical parts has been recently used in wide area with modification of thermal properties using alkali oxides. It is our purpose to find a correlation between thermal expansion coefficient, glass transition temperature and melting temperature through investigating thermal properties in P$_2$O$\sub$5/-SnO-ZnO-SiO$_2$/B$_2$O$_3$. As a result, the product of thermal expansion coefficient and the glass transition temperature in the glasses is found to be a constant value would be a unique value for knowing one of thermal properties.

• Journal of the Korean Ceramic Society
• /
• v.29 no.6
• /
• pp.451-458
• /
• 1992

Dense glass-ceramics for low firing temperature substrate were prepared by addition of CeO2 flux to the glass of MgO-Al2O3-SiO2 system. Glass powders were fabricated by melting at 150$0^{\circ}C$ and ball milling. Glass powder compacts were sintered at 800~100$0^{\circ}C$ for 3h. The crystallization and the shrinkage behaviors of glass powder compacts were analyzed by XRD, DTA and TMA. The shrinkage of glass powder compact increased with increasing the amount of CeO2. Because the softening temperature decreased and the crystallization temperature increased with increasing the amount of CeO2. Apparently, addition of CeO2 prevented formation of $\mu$-cordierite phase from the glass-ceramics and improved formation of $\alpha$-cordierite phase. Therefore crystallization properties were enhanced.

• Conservation Science in Museum
• /
• v.4
• /
• pp.23-32
• /
• 2003

As the kettle excavated from a site in Hwangnam-dong, Gyeongju was presumed to have been used as a melting crucible in a glass production workplace, we decided to prove its usage by scientific analysis. First, we performed conservation treatment to find the original status of the kettle, and then SEM-EDS and XRD analysis of the five corrosions created on the surface of the kettle. The fragment of the spout, which played a crucial role for the kettle to be considered as a melting crucible, was discovered during the conservation treatment. So the mouth rim of the kettle was restored to perfection. When we observed the microstructure of the metal sample, it was proved to be cast iron gradually cooled without heat treatment. In the corrosion products, the main components were Fe and O and other components such as P, Si, Ca, and S were found. The main compounds were quartz, vivianite, goetheite, akaganite, lepidocrocite, hematite, etc. Although these components were used as raw materials for making glass, these were found not in the melting status but mere raw materials. This can be an evidence to show these site where the kettle was excavated had been a glass production workplace. However, it is not sure that the kettle was used as a melting crucible. Moreover, if we consider the organic mold and sand clay accumulated in the well site when the kettle was excavated at first, we can see this as a formative factor of the corrosions of the kettle. Therefore, we concluded that the kettle is a typical cast iron and was not used as a melting crucible of glass.

• Journal of the Korean Ceramic Society
• /
• v.31 no.12
• /
• pp.1545-1551
• /
• 1994

Various kinetic parameters of the nucleation and crystallization in anorthite glass (CaO.Al2O3.2SiO2) were calculated by nonisothermal differential thermal analysis. Base glass and glass with TiO2 were prepared by melting. In base glass, the temperature where nucleation can occur ranges from 85$0^{\circ}C$ to 9$25^{\circ}C$ and the temperature for maximum nucleation was 900$\pm$5$^{\circ}C$. In glass with TiO2, the nucleation temperature range was 800~875$^{\circ}C$ and the maximum nucleation temperature was 850$\pm$5$^{\circ}C$. Kissinger equation, Bansal equation, and modified Ozawa equation were used for calculating activation energy for crystallization, Ec. The results showed the same activation energies for both glasses with and without TiO2 in the different equations. The shape of maximum exotherm peak and Ozawa equation were used for Avrami exponent, n. The n value for each glass was 2, indicating that each glass crystallized primarily by bulk crystallization.

• Journal of Technologic Dentistry
• /
• v.30 no.1
• /
• pp.41-47
• /
• 2008

This study was to evaluate the biaxial flexural strength of zirconia ceramics after glass-infiltration on zirconia core. The zirconia specimens were made with diameter-15mm, thickness-0.6mm using zirconia block which divided into 1) sintered group, 2) heat - treated group, 3) Glass - infiltrated group and experimented fracture strength by each 10 specimens in experimental group. The biaxial flexural test was performed at crosshead speed of 0.1${\beta}\;{\AE}$ min. The experiment result average fracture strength was shown 541.0${\beta}\acute{A}$ in sintered group and glass-infiltrated group as 662.2${\beta}\acute{A}$ river of 22.4% rise appear. Weibull coefficient sintered group is 3.462 and glass-infiltrated group improved believability about fracture strength from melting permeation processing of glass by 4.716.