• Journal of the Korean Ceramic Society
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• v.41 no.11
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• pp.851-857
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• 2004

The stabilizing characteristics of heavy metals in the silicate glass (SD), borosilicate glass (BD), and leadsilicate glass (PD) containing Electric Arc furnace (EAF) dust were studied by the Toxic Characterization Leaching Procedure (TCLP) test. Also, the dependence of the amount of EAF dust upon structural changes of SD, BD, and PD glasses and the TCLP results were investigated by the XRD and FT-IR spectroscopy. In the XRD results, all of SD, BD, and PD specimens containing dust up to 30 wt% were amorphous without crystallizing. In the TCLP test, the concentration of heavy metals leached from the glasses increased with the amount of EAF dust added. The SD specimen series showed the lowest heavy metal leaching and the heavy metal leachate of the PD specimens were lower than those of the BD specimens. But, the Pb leaching from the PD specimens was the highest in the PD glass composition due to the high Pb content. The value of oxygen/network former ratio could be used to compare the chemical durability within the same glass series, but not proper to do between the different glass series. Adding the EAF dust to the SD mother glass, decreased the Si-O-Si symmetry and increased the non-bridging oxygen, which weakened the structure and decreased the chemical durability of glasses. In the BD series glasses, the addition of EAF dust caused the structural changes from tetra-borate group to di-borate group and the formation of the 2-dimensional layer structure of pyre- and ortho- borate, which decreased the chemical durability of glasses. It is concluded that SD series glass among the 3 kinds of glasses is the most effective to stabilize the heavy metals of EAF dust.

• 대한치과보철학회:학술대회논문집
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• 1996.11a
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• pp.52-52
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• 1996

• Journal of the Mineralogical Society of Korea
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• v.26 no.2
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• pp.119-127
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• 2013

Borosilicate glass dissolution is an important chemical process that impacts the glass durability as nuclear waste form that may be used for high-level radioactive waste disposal. Experiments reported that the glass dissolution rates are strongly dependent on the bulk composition. Because some relationship exists between glass composition and molecular-structure distribution (e.g., non-bridging oxygen content of $SiO_4$ unit and averaged coordination number of B), the composition-dependent dissolution rates are attributed to the bulk structural changes corresponding to the compositional variation. We examined Na borosilicate glass structures by performing classical molecular dynamics (MD) simulations for four different chemical compositions ($xNa_2O{\cdot}B_2O_3{\cdot}ySiO_2$). Our MD simulations demonstrate that glass surfaces have significantly different chemical compositions and structures from the bulk glasses. Because glass surfaces forming an interface with solution are most likely the first dissolution-reaction occurring areas, the current MD result simply that composition-dependent glass dissolution behaviors should be understood by surface structural change upon the chemical composition change.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.3
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• pp.31-36
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• 2001

Dielectric material which is suitably designed for the application of the high-temperature electrostatic chucks(HTESCS) has been developed. Electrical resistivities and dielectric constants of the dielectric layer satisfy the demands for the proper operation of HTESC, and coefficient of thermal expansion(CTE) of the dielectric material matches well that of the bottom insulator so that it secures stable structure. In order to minimize particle contaminations, borosilicate glass(BSG) is selected as a bonding layer between dielectric layer and bottom insulator, and silver is used as a electrode. BSG is solidly bonded between upper dielectric and bottom insulator, and no diffusions or reactions are observed among silver electrode, dielectric, and glass layers. The chucking characteristics of the fabricated HTESC are found to be superior to those of the commercialized one.

• Journal of the Korean Ceramic Society
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• v.38 no.11
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• pp.1000-1007
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• 2001

In an evacuated tube solar collector, the stable sealing of the heat pipe to the glass tube is important for the collector to use for a long period of time. The sealing of copper tube to the glass is quite difficult because of the large differences in the physical and chemical properties of the two materials. In this study, therefore, a proper copper oxide layer was induced to improve the chemical bonding of the two materials, and the oxidation state of copper and the interface between copper and glass were examined by XRD, SEM and EDS. Its bonding strength was also measured. Cu$_2$O was formed when the bare copper was heat-treated under 600$^{\circ}C$, while CuO oxide layer was formed above that temperature. The bonding state of CuO to the copper was very poor. The borate treatment of the copper, however, extend the stable forming of Cu$_2$O layer to 800$^{\circ}C$. Borosilicate glass tube was sealed to a copper tube by Housekeeper method only when the sealing part was covered with Cu$_2$O layer. The bonding strength at the interface was measured 354.4N, its thermal shock resistance was acceptable.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.1
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• pp.49-56
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• 2010

In the pyroprocessing of spent nuclear fuels, LiCl-KCl waste salt containing radioactive rare earth chlorides are generated. The radioactive rare earth oxides are recovered by co-oxidative precipitation of rare earth elements. The powder phase of rare eath oxide waste must be immobilized to produce a monolithic wasteform suitable for storage and ultimate disposal. The immobilization of these waste developed in this study involves a solid state sintering of the waste with host borosilicate glass and zinc titanate based ceramic matrix(ZIT). And the rare-earth monazite which synthesised by reaction of ammonium di-hydrogen phosphate with the rare earth oxides waste, were immobilzed with the borosilicate glass. It is shown that the developed ZIT ceramic wasteform is highly resistant the leaching process, high density and thermal conductivity.

• Journal of the Microelectronics and Packaging Society
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• v.9 no.1
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• pp.49-52
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• 2002

This study demonstrated the feasibility of tape casting method to fabricate soda borosilicate glass-coated stainless steel electrostatic chucks(ESC) for low temperature semiconductor processes. Glass coating on the stainless steel substrate was 125 $\mu\textrm{m}$ thick. The adhesion of glass coating was found to be excellent such that it was able to withstand temperature cycling to over $300^{\circ}C$ without cracking and delamination. The electrostatic clamping pressure generally followed the theoretical voltage-squared curve except at elevated temperatures and high applied voltages. The deviations at elevated temperatures and high applied voltages are due to increased leakage current as the electrical resistivity of glass coating drops.

• Analytical Science and Technology
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• v.13 no.6
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• pp.775-780
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• 2000

The electrical conductivity of glass melter at high temperature has been measured. The conductivity is an important physical property for the research and the manufacturing process of glass. Because high temperature is an inconvenient situation to measure the conductivity of glass melter, we have made a platinum crucible and electrode and have measured the conductivity at high temperature. KCl solution, of which concentration is adjusted to the conductivity of glass melter, is used to get parameters of the conductivity cell. A measuring circuit is composed with an AC 1 kHz sine wave generator and an operational amplifier. The cell constants are determined from the measured voltages and the equivalent conductances of KCl solution. Various cells are tested to find a suitable shape for high temperature experiment. The results are compared by cell size, electrode depth, and cell configuration. The conductivity of the borosilicate melter is $0.053{\Omega}^{-1}cm^{-1}$ at $1,450^{\circ}C$.

• Journal of the Korean Ceramic Society
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• v.29 no.12
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• pp.956-962
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• 1992

The predominant sintering mechanisms of low firing temperature ceramic substrate which consists of borosilicate glass containing alumina as a filler are the rearrangement of alumina particles and the viscous flow of glass powders. In this system, sintering condition depends on the volume ratio of alumina to glass and on the particle size. When the substrate contains about 35 vol% alumina filler and the average alumina particle size is 4 $\mu\textrm{m}$, the best firing condition is obtained at the temperature range of 900∼1000$^{\circ}C$. The extensive rearrangement behavior occurs at these conditions, and the optimum sintering condition is attained by smaller size of glass particles, too. The formation of cristobalite during sintering causes the difference of thermal expansion coefficient between the substrate and Si chip. This phenomenon degradates the capacity of Si chip. Therefore, the crystallization should be prevented. In the alumina filled borosilicate glass system, the crystallization does not occur. This effect may have some relation with aluminum ions in alumina. For aluminum ions diffuse into glass matrix during sintering, functiong as network former.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.390-393
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• 2001

This study demonstrated the feasibility of tape casting method to fabricate soda borosilicate glass-coated stainless steel electrostatic chucks(ESC) for low temperature semiconductor processes. The glass coatings on the stainless steel substrates ranged from $100{\mu}m$ to $150{\mu}m$ thick. The adhesion of the glass coatings was found to be excellent such that it was able to withstand moderate impact tests and temperature cycling to over $300^{\circ}C$ without cracking and delamination. The electrostatic clamping pressure generally followed the theoretical voltage-squared curve except at elevated temperatures and higher applied voltages when deviations were observed to occur. The deviation is due to increased leakage current at higher temperature and applied voltage as the electrical resistivity drops.