• Korean Journal of Materials Research
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• v.34 no.2
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• pp.79-84
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• 2024

Thin films of yttria-stabilized zirconia (YSZ) nanoparticles were prepared using a low-temperature deposition and crystallization process involving successive ionic layer adsorption and reaction (SILAR) or SILAR-Air spray Plus (SILAR-A+) methods, coupled with hydrothermal (175 ℃) and furnace (500 ℃) post-annealing. The annealed YSZ films resulted in crystalline products, and their phases of monoclinic, tetragonal, and cubic were categorized through X-ray diffraction analysis. The morphologies of the as-prepared films, fabricated by SILAR and SILAR-A+ processes, including hydrothermal dehydration and annealing, were characterized by the degree of surface cracking using scanning electron microscopy images. Additionally, the thicknesses of the YSZ thin films were compared by removing diffusion layers such as spectator anions and water accumulated during the air spray plus process. Crack-free YSZ thin films were successfully fabricated on glass substrates using the SILAR-A+ method, followed by hydrothermal and furnace annealing, making them suitable for application in solid oxide fuel cells.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.16 no.5
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• pp.227-234
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• 2006

Microstructures of free surface and interior of glass-ceramics obtained by heat treating silicate glass specimen containing electric arc furnace dust(EAF dust) were observed. The crystallization temperature, $T_c$ of glassy specimen was measured around $850^{\circ}C$ from the result of different thermal analysis so heat treatment temperature to obtain glass-ceramic specimen was selected as $950^{\circ}C$ for 1 hr. Glass specimens containing 50 wt% dust were amorphous, while glass specimens containing 70 wt% dust showed spinel crystal peaks in XRD results. In case of glass-ceramic specimens, spinel crystalline phase was appeared with willemite, and willemite crystal peak intensity increased with increasing dust contents. The fractured surface of glass specimens containing 50 wt% dust was smooth like mirror surface, but that containing 70 wt% dust showed spinel crystals of 10 ${\mu}m$ size in glass matrix. In case of glass-ceramic specimens, ZnO crystal particles of $2{\sim}5{\mu}m$ size were produced in free surface and glassy phase, spinel and willemite crystal phases existed in interior. There were no crystals in glasses containing 50 wt% dust, while glass containing 70 wt% dust had 14 vol% crystals. Crystallinity of glass-ceramic specimens containing 50 and 70 wt% dust were 19 and 43%, respectively. When microstructures of glass and glass-ceramic specimens were observed through SEM after TCLP experiment, glass specimens showed flaking phenomenon while glass-ceramic specimens showed a slight corrosion evidence without any cracks.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.2
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• pp.136-142
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• 2016

As the rapid industrialization and modernization progress of the world it is becoming a fast-paced environment pollution. And, dust or environment pollution to solve reckless diggings of natural aggregate cause a serious problem. This study was used a Blast Furnace Slag and Combined Heat and Power Plant of Fly Ash as a cement substitute to reduce $CO_2$ emissions during cement production, this study intend to suggest it's result as basic data 'Properties of Artificial Stone interior or exterior materials type utilizing industrial by-product and waste resource' utilizing Waste Porcelain and Waste Glass. As a result, it was high strength that matrix added the Combined Heat and Power Plant of Fly Ash of addition ratio 40%. Also, pre-experiment was conduct as mixing ratio of waste glass, waste porcelain on the basis of the preceding experiment, proper mixing ratio was judged that proper of waste glass, waste porcelain was mixing ratio 60, 70 (%) of appeared surface aggregate ratio more than 45%.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.1
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• pp.169-178
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• 1998

The crystal phases precipitated in various compositions glass of CaO-$SiO_2-P_2O_5$ system, were identified by XRD. E composition (CaO 49.4, $SiO_2\;36.8,\;P_2O_5$ 8.8 wt%) glass in which both apatite(($Ca_{10}(PO_4)_6O$ and $\beta$-wollastonite($CaSiO_3$) crystals would precipitate by heating, was selected as an experimental composition to prepare the glass ceramics with high bending strength and good bioactivity to the living bone. Glass powders of E composition were unidirectionally crystallized at $1050^{\circ}$C in the temperature-gadient furnace and the resultant glass ceramics were characterized. Bending strength of the glass ceramics was also measured. To investigate the bond forming ability between the glass ceramics and living bone tissue, soaking test of glass ceramics in simulated body fluid was carried out. Densed glass ceramics composed of apatite and $\beta$-wollastonite crystal were prepared by unidirectional crystallization under the optimum conditions. (2 0 2) plane of $\beta$-wollastonite crystals tended to grow perpendicularly to the crystallization direction. Average bending strength of this glass ceramics was 186.9 MPa, higher than that of the glass ceramics prepared by isothermal (not directional) crystallization In soaking test, a thin layer of apatite crystallite was formed on surface of the glass ceramics in 3 days. Apatite crystals formed on the glass ceramics could be act a role to make the chemical bond between the glass ceramics and living bone tissue.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.391-396
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• 2001

Exposed concrete execution is utilized insufficiently due to surface honecomb and undesirable appearance by entrapped air when existing placing method is applied. Therefore, surface glossing and impact properties of cement mortar incorporating fiber glass net blast furnace slag, expansive admixture and Polypropylene fiber are investigated in order to develop precast exposed concrete pannel by dry construction method. The kinds of the forms, placing method and admixture contents are varied. According to test results, surface glossing decrease with elapse of age. Considering the form kinds, surface glossing with acryle + astage shows the best performance. Placing horizontally shows positive results in reducing surface defects such as honecomb. Impacting resistance shows the best performance when glass fiber net applied, due to the enhance in toughness and absorption of impact.

• Journal of the Korean Ceramic Society
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• v.34 no.9
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• pp.935-940
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• 1997

This study investigated the crystallization behavior in PbO-ZnO-B2O3-TiO2 system sealing glass, inorganic polymer heat-treated by conventional heat and microwave energy. After determining heat-treated temperature for crystallization and characteristic points by DTA analysis, samples were heat-treated in a classical electric furnace and a home-style microwave oven (LG Electronic Co., 2.45 GHz, 700 W). A microwave heat-treated sample had the growth of PbTiO3 crystal at 45$0^{\circ}C$, 2$0^{\circ}C$ lower than that of a conventionally heat-treated sample. Also, it had crystallinity about 20% higher than the conventionally heat-treated sample. At 49$0^{\circ}C$, the size of PbTiO3 crystal in the conventionally heat-treated sample was larger than that in the microwave heat-treated sample due to longer heat-treated time.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.4
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• pp.35-39
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• 1999

The $Li_2O-MgO-MgF_2-SiO_2$glasses with addition of $B_2O_3$ were investigated in order to make glass-ceramics for low temperature firing substrate. Glasses were made by melting at $1450^{\circ}C$ in the electronic furnace and crystallized at $750^{\circ}C$. The crystal phases were polycrystalline of lithium boron fluorphlogopite and lithium fluorhectorite. The crystal shape was chanced to granule type from needle type with increasing $B_2O_3$ content. Average particle size of the glass-ceramics after water swelling was 3.77$\mu\textrm{m}$. The optimum sintering temperature and sintering shrinkage of the substrate were $900^{\circ}C$ and 13.4%, respectively.

• Journal of Ceramic Processing Research
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• v.21 no.2
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• pp.213-216
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• 2020

We investigated the optimal conditions for the manufacture of a rapid SiC heating element with increased durability for a flipchip bonder. In the moulding step prior to the sintering of the SiC heating element, a pressure of either 25 or 125 MPa wasapplied by uniaxial pressing to control the micropores; this was aimed at improving the resistance of the ultimate specimen. The moulded specimen was sintered by using a vacuum furnace with silicon as a sintering additive. The measurement of thehot modulus of rupture (HMOR) of the resulting SiC sintered body revealed that the HMOR was high. In addition, a methodfor protecting the heating element from the external environment was developed. A glassy coating layer was deposited on thesurface of the structure to improve the corrosion resistance of the sintered body; further, the performance of the coating layerwas verified through a neutral and acidic salt spray test. Finally, we established the optimal process conditions formanufacturing a rapid SiC heating element with improved corrosion resistance.

• Proceedings of the KAIS Fall Conference
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• 2002.05a
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• pp.70-73
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• 2002

도가니로를 사용하여 유리제품을 생산하고있는 중소 유리제조업체인 D.H사의 제품내 발생한 결함을 분석하였다. 제품내 결함으로는 기포, 코드(cord), 석물(stone)이 발생하고 있었으며, 광학현미경, EDS 등의 분석장비를 통해 제품내 결함을 분석한 결과 코드는 석물에 의해 발생하고 있음을 확인하였다. 석물의 EDS 분석결과 주요성분은 Si로 나타났으며, 이는 도가니의 장기간 사용시 도가니 내벽과 유리물의 반응에 의한 도가니의 용융침식에 의해 발생한 한가지 결점원에 의한 한가지 결정상으로 SiO₂의 고온결정상인 cristobalite임을 확인할 수 있었다.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.946-948
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• 2006

It is important to keep a constant transmittance of dielectric during firing. To control the shrinkage and fusion stage of frits in firing, we used a hot stage microscope (HSM) to analyze the thermal properties of the lead and bismate glass frits by the in-situ method. This research would be useful for improving the reliability of transmittance of dielectric during firing in industry using a large furnace with temperature deviation.