• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.344-349
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• 2005

This paper is studied on the effect of TiAlN coated ball end mill on cutting characteristic of high hardness steels in dry cutting condition without coolant. KP4 steels[HRC32] and STD11[HRC60] heat treated steels wert: used as the workpiece and WC-Co ball end mill and single and multi layer TiAlN coated ball end mill were utilized. Results showed that TiAlN coated ball end mill were increased the cutting length than WC-Co ball end mill in the cutting speed$[245\~320m/min]$ about $2\~5$ times for KP4 steels and about $2.7\~4.3$ times for STD11 heat treated steels. The multi layer TiAlN coated ball end mill is good about $1.2\~1.7$ times for KP4 steels and STD11 steels than single layer coated.

• Journal of the Korean institute of surface engineering
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• v.33 no.1
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• pp.3-9
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• 2000

Arc-melted alloys of TiAl-(o.25, 0.5, 1.0at%) Si were isothermally oxidized at 800, 900 and $1000^{\circ}C$ in air for 60hr. It was found that the oxidation resistance of the prepared TiAl-Si alloys was much better than that of pure TiAl, being progressively increasing with an increase in the Si content. This was attributed to the formation of $SiO_2$in addition to ($TiO_2$+$Al_2$$O_3$) oxides which formed in TiAl alloys with and without silicon additions. However, the silica formation within the oxide layer unfortunately accelerated the oxide scale spallations. During oxidation, all the elements in the base alloy diffused outward, whereas oxygen from the atmosphere diffused inward. The oxides were primarily composed of an outer thick $TiO_2$layer, an intermediate diffuse $Al_2$$O_3$layer and an inner $TiO_2$layer. A small amount of $SiO_2$was present all over the oxide scale and some voids were found around the intermediate layer.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.513-516
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• 2008

The luminance efficiency of the red organic light-emitting devices fabricated utilizing a double electron transport layer (ETL) consisting of an Al-doped and an undoped layer was investigated. The Al atoms existing in the ETL acted as hole blocking sites, resulting in an increase in the luminance efficiency.

• Journal of the Korean Ceramic Society
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• v.34 no.1
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• pp.88-94
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• 1997

The oxidation behavior of the NiCrAlY bond coat and thermal fatigue failure in the plasma-sprayed thermal barrier coating system, ZrO2.8wt%Y2O3 top coat/Ni-26Cr-5Al-0.5Y bond coat/Hastelloy X superalloy substrate, in commercial use for finned segment of gas turbine burner were investigated. The main oxides formed in the bond coat were NiO, Cr2O3, and Al2O3. It divided the oxide distribution at this interface into two types whether an Al2O3 thin layer existed beneath ZrO2/bond coat interface before operation at high temperature or not. While a continuous layer of NiO was formed mainly in the region where the Al2O3 thin layer was present, the absence of it resulted in the formation of mixture of Cr2O3 and Al2O3 beneath NiO layer. Analyses on the fracture surface of specimen spalled by thermal cycling showed that spalling occurred mainly along the ceram-ic coat near ZrO2/bond coat oxide layer interface, but slightly in the oxide layer region.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.11
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• pp.711-714
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• 2015

In this paper, high quality AlN layers were regrown on AlN nanopillar structure with $SiO_2$-dots by HVPE. Surface morphology of AlN layer regrown exhibited flatter than a conventional AlN template. The laterally overgrown AlN regions would consist of a continuous well coalesced layer with lower dislocation density than in the template because of the dislocation blocking and dislocation bending effects. Moreover, result of Raman spectroscopy suggest that the AlN nanopillar structure with $SiO_2$-dots relieves the strain in the AlN layer regrown by HVPE.

• Journal of Information Display
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• v.6 no.3
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• pp.26-29
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• 2005

Nanosize cobalt aluminate($CoAl_2O_4$) power was coated as filter layer for us to improve the color purity and contrast performances on the inner face of CRT panel. We simulated color properties by measuring the transmittance and thickness of the coated filter layer. Contrast performance could be improved and color gamut was also changed by the selective light absorption of filter layer at 580${\sim}$605 nm.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1321-1323
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• 1998

We investigated drain leakage current in GaAs power MESFET. The device we studied by 20 simulation has a $1000{\AA}$ thick AlGaAs buffer layer under n-GaAs active layer. The calculation shows that the leakage current through GaAs substrate is significantly reduced by the buffer layer.

• Korean Journal of Materials Research
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• v.28 no.6
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• pp.324-329
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• 2018

Needle-like NiO protecting layers on NiCrAl alloy foam, used as support for hydrogen production, are introduced through electroplated Ni and subsequent microwave annealing. To improve the stability of the NiCrAl alloy foam, oxygen concentration of microwave annealing to form a needle-like NiO layer with good chemical stability and corrosion resistance is controlled in a range of 20 and 50 %. As the oxygen concentration increases to 50 %, needle-like NiO forms a dense coating layer on the NiCrAl alloy foam; this layer formation can be attributed to accelerated growth of the (200) plane. In addition, the increased oxygen concentration causes increased NiO/Ni ratio of the resultant coating layer on NiCrAl alloy foam due to improved rate of the oxidation reaction. As a result, the introduction of dense needle-like NiO layers formed at 50 % oxygen concentration improves the chemical stability of the NiCrAl alloy foam by protecting the direct electrochemical reaction between the electrolyte and the foam. Thus, needle-like NiO can be proposed as a superb protecting layer to improve the chemical stability of NiCrAl alloy form.

• Proceedings of the Materials Research Society of Korea Conference
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• 1996.11a
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• pp.42-42
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• 1996

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04c
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• pp.42-44
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• 2008

In this study, we report an electrical properties of green OLEO, using the changed thickness of Al Layer. We investigated the electrical properties of OLEOs by IVL and optical properties by EL spectrum. The fundamental structure of green OLEOs was ITO anode/TPD($400{\AA}$)/$Alq_3(600{\AA})$)/LiF($10{\AA}$)/Al($200{\sim}600{\AA}$) cathode. The threshold voltage was low value according to the more thin Al layer. The luminance was increased by decreased cathode layer. The threshold voltage was 12V and wavelength was 530nm at $200{\AA}$ cathode.