• Journal of the Korean Ceramic Society
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• v.53 no.6
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• pp.700-706
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• 2016

Etch rate, surface roughness and microstructure as plasma resistance were evaluated for six kinds of oxide glass with different compositions. Borosilicate glass (BS) was found to be etched at the highest etch rate and zinc aluminum phosphate glass (ZAP) showed a relatively lower etch rate than borosilicate. On the other hand, the etching rate of calcium aluminosilicate glass (CAS) was measured to be similar to that of sintered alumina while yttrium aluminosilicate glass (YAS) showed the lowest etch rate. Such different etch rates by mixture plasma as a function of glass compositions was dependent on whether or not fluoride compounds were formed on glass and sublimated in high vacuum. Especially, in view that $CaF_2$ and $YF_3$ with high sublimation points were formed on the surface of CAS and YAS glasses, both CAS and YAS glasses were considered to be a good candidate for protective coating materials on the damaged polycrystalline ceramics parts in semi-conductor and display processes.

• Journal of the Korean Ceramic Society
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• v.35 no.3
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• pp.259-263
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• 1998

WSi2/CVD-Si/SiO2/Si-substrate의 폴리사이드 구조에서 실리콘 증착 POCl3 확산 그리고 WSi2 증착 유무에 따른 Thin oxide 특성을 연구했다 WSi2 막을 증착하지 않은 CVD-Si/SiO2/Si-substrate 구조에서 CVD-Si을 po-lycrystalline-Si으로 증착한 시편이 amorphous-Si을 증착한 시편보다 산화막 불량이 적다 WSi2 를 증착시킨 WSi2/CVD-Si/SiO2./Si-substrate의 구조에서 CVD-Si의 polycrystalline-Si 혹든 amorphous-Si 의 막 증착에 따른 thin oxide의 불량율 차이는 미미하다 산화막 불량은 CVD-Si에 확산시킨 인(P) 증가 즉 면저항(sheet resistance) 감소로 증가한다. Thin oxide의 절연특성은 WSi2 증착으로 저하된다 WSi2 증착으로 산화막 두께는 증가하나 막 특성은 열등해져 산화막 절연성이 떨어진다.

• Journal of the Korean Ceramic Society
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• v.43 no.8 s.291
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• pp.479-485
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• 2006

The residual stress changes on thermo-mechanical loading in the interface region of the Thermal Barrier Coating (TBC)/Thermally Grown Oxide (TGO)/Bond Coat (BC) were calculated on the TBC-coated superalloys using a Finite Element Method (FEM). It was found that the residual stress of the interface boundary was dependent upon mainly the oxide formation and the swelling rate of the oxide by creep relaxation. During an oxide swelling, the relaxation of residual stress which is due to creep deformation increased the TBC's life. In the case of the fine grain size of TGO scale, the TBC stresses piled up by oxide swelling could be relaxed by diffusional creep effect of TGO.

• Journal of the Korean Society of Safety
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• v.20 no.2 s.70
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• pp.1-5
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• 2005

An experimental study was conducted to develop an understanding of failure of ceramic coating when subjected to a thermal cycling. Number of cycles to failure were decreased as the coating thickness and the oxide of bond coat were increased. Using the finite element method, an analysis of stress distribution in ceramic coatings was performed. Radial compressive stress was increased in the top/bond coat interface with increasing coating thickness and oxide of bond coat.

• Journal of the Korean Ceramic Society
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• v.31 no.10
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• pp.1197-1201
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• 1994

The fracture strength and fracture modes were studied in 3Y-TZP/NiNi bonding which change their interfacial structure with bonding condition. Average 4-point bending strength of 200 MPa to 400 MPa were achieved. The formation of Ti-oxide phase at the interface critically influenced the bonding strength and fracture mode. The fracture surface of Ti-oxide free interface contained multiphase in some case including ZrO2. From the result it was confirmed that in order to maximize the bonding strength crack deflection from interface to ceramic was required.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.5
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• pp.243-248
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• 2017

In this study copper glaze samples were prepared with varying amount of tin oxide, and the chromatic characteristics of glazes were explained on the results of spectrophotometric, crystalline phase, and microstructural analyses. The red color of copper glaze was dissipated with the addition of tin oxide and turned into achromatic color due to the decrease of CIEab values. Tin oxide homogeneously distributed in the glaze layer interfered with the red color generation coming from the growth of Cu nuclei, and formed an alloy with metal copper around bubbles. This resulted in the decrease of metal copper peak intensity with minor $Cu_2O$ peak. With the 3.79 % tin oxide addition the glaze was appeared as gray due to the black color CuO and Cassiterite $SnO_2$ phases.

• Journal of Technologic Dentistry
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• v.31 no.2
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• pp.23-30
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• 2009

All-ceramic restorations have gained acceptance among clinicians and patients because of their superior esthetics. Most all-ceramic systems have a 2-layer structure, using a weak veneering ceramic over a strong supporting core. often, failure of all-ceramic restorations occurs when the veneering ceramic fractures, exposing the core material. The purpose of this study was to compare the shear bond strength of heat press ceramic system (Zirpress) to zirconia core with various surface treatments. 10 metal cores and 50 zirconia cores were fabricated and divided into six groups according to surface treatment such as Zirliner application, aluminium oxide blasting, and 9.5% HF etching. Sixty specimens were prepared using Zirpress, veneered 8mm height and 3mm in diameter, over the zirconia cores (n=10). The shear bond strength test was performed in a universal testing machine with a crosshead speed of 1/min. Ultimate shear bond strength data were analyzed with One-way ANOVA and the Scheffe's test (p=.05). Within the limits of this study, the following conclusions were drawn: The mean shear bond strengths (MPa) were: 12.93 for $110{\mu}m$ aluminium oxide blasting/Rexillium III/IPS e.Max Zirpress; 14.92 for $50{\mu}m$ aluminium oxide blasting ${\pm}9.5%$ HF etching/Zirconis core/IPS e.Max Zirpress; 16.37 for $110{\mu}$ aluminium oxide blasting + 9.5% HF etching/Zirconis core/IPS e.Max Zirpress; 12.89 for $200{\mu}$ aluminium oxide blasting + 9.5% HF etching/Zirconis core/IPS e.Max Zirpress; 19.30 for 9.5% HF etching/Zirconis core/IPS e.Max Zirpress; 19.55 for Zirliner/Zirconis core/IPS e.Max Zirpress. The mean shear bond strength for ZNTZH (Zirliner/Zirconis core) and ZNTEH (9.5% HF etching/Zirconis core) were significantly superior to MS110H ($110{\mu}$ aluminium oxide blasting/Rexillium III) and ZS200EH ($200{\mu}$ aluminium oxide blasting + 9.5% HF etching/Zirconis core) (p<0.05).

• Transactions on Electrical and Electronic Materials
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• v.16 no.4
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• pp.194-197
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• 2015

La_9.33(Si₅V₁)O₂₆ ceramics were fabricated by the mixed oxide method for solid oxide electrolytes. La_9.33(Si₅V₁)O₂₆ specimens showed the hexagonal, space group P63 or P63/m, and the unit cell volume increased when the sintering temperature increased. The specimen sintered at 1,400℃ showed the X-ray patterns of the homogeneous apatite single phase without the second phase, such as La₂SiO₅ and SiO₂. The specimen sintered at 1,400℃ showed the maximum sintered density of 4.93 g/cm³. When the sintering temperature increased, the electrical conductivities increased, the activation energy decreased and the values were 7.83×10⁻⁴ S/cm, 1.61 eV at 600℃, respectively.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.09a
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• pp.97-102
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• 1998

Transition metal Cr3+ and Fe3+ ion was diffused in white sapphire {0001}, {1010} crystal plane which were grown by the Verneuil method. It enhanced and changed the physical, electrical and optical properties of sapphires. After mixing the metallic oxide and metal powder, it were used for diffusion. Metallic oxide was synthesized by precipitation method and it's composition was mainly alumina which doped with chromium or ferric oxide. In case using metallic oxide, the dopping was slowly progressed and it needed the longer duration time and higher temperature, relatively. Metallic powder was vapoured under 1x10-4 torr of vacuum pressure at 1900(iron metal) and 2050(chromium)℃, first step. Diffusion condition were kept by 6atm of N2 accelerating pressure at 2050∼2150℃. Each surface density of sapphire crystal are 0.225(c) and 0.1199atom/Å2(a). The color of the Cr-doped sapphires was changed to red. Dopping reaction was come out more deep in th plane of {1010} than {0001}. It was speculated that the planar density was one of the factors to determine diffusion effect.

• Transactions on Electrical and Electronic Materials
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• v.7 no.4
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• pp.167-172
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• 2006

Submicron colloidal silica coated with ceria were prepared by mixing of silica and nano ceria particles and modified by hydrothermal reaction. The polishing efficiency of the ceria coated silica slurry was tested over oxide film on silicon wafer. By changing the polishing pressure in the range of $140{\sim}420g/cm^2$ with the ceria coated silica slurries in $100{\sim}300nm$, rates, WIWNU and friction force were measured. The removal rate was in the order of 200, 100, and 300 nm size silica coated with ceria. It was known that the smaller particle size gives the higher removal rate with higher contact area in Cu slurry. In the case of oxide film, the indentation volume as well as contact area gives effect on the removal rate depending on the size of abrasives. The indentation volume increase with the size of abrasive particles, which results to higher removal rate. The highest removal rate in 200 nm silica core coated with ceria is discussed as proper combination of indentation and contact area effect.