• Journal of the Korean Vacuum Society
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• v.17 no.2
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• pp.96-101
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• 2008

The magnesium oxide (MgO) protective layer plays an important role in plasma display panels (PDPs). Our previous work demonstrated that the properties of MgO thin film could be improved, which were deposited by Ion-Beam-Assisted Deposition (IBAD). However arc discharge always occurs during the IBAD process. To avoid this problem, Oxygen-Neutral-Beam-Assisted Deposition (NBAD) is used to deposit MgO thin films in this paper. The energy of the oxygen neutral beam was used as the parameter to control the deposition. The experimental results showed that the oxygen neutral beam energy was effective in determining in structural and discharge characteristics. The lowest firing inception voltage, the highest brightness and the highest luminous efficiency were obtained when the MgO thin film was deposited with an oxygen neutral beam energy of 300eV. The surface morphology of MgO thin film was also analyzed using AFM (Atomic Force Microscopy) and SEM (Scanning Electron Microscopy).

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.6
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• pp.324-327
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• 2009

In the present study, the effect of Ca additions on the ignition and combustion behaviors of Mg alloys has been investigated. Cracks and inclusions were observed at the free surface and interior in as-cast pure magnesium but not in Ca-bearing Mg alloys. There was a tendency that ignition temperature rapidly increased with increasing Ca content in Mg-Ca alloy. Saturated composition for increasing of ignition temperature was related with solid solubility of Ca in Ca-bearing Mg alloys. The protective oxide layers, MgO, could also be found on the combustion surface of Ca-bearing magnesium alloy.

• Journal of the Korean Vacuum Society
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• v.16 no.5
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• pp.338-342
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• 2007

The magnesium oxide (MgO) protective layer plays an important role in plasma display panels (PDPs). In this paper, we describe the structural and discharge properties of MgO thin films, which were prepared by the ion-beam-assisted deposition (IBAD) of oxygen as the protective layer of PDPs. The energy of the oxygen ion beam was used as the parameter to control the deposition. We found that the oxygen ion beam energy was effective in determining in structural and discharge characteristics. The lowest firing inception voltage, the highest brightness and the highest luminous efficiency were obtained when the MgO thin film was deposited with an oxygen ion beam energy of 300 eV. The crystallization of the MgO thin film was also measured by X-ray diffraction analysis, and the surface quality was measured by atomic force microscopy.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2001.11a
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• pp.35-35
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• 2001

agnesium Oxide (MgO) with a NaCI structure is well known to exhibit high secondary electron emission, excellent high temperature chemical stability, high thermal conductance and electrical insulating properties. For these reason MgO films have been widely used for a buffer layer of high $T_c$ superconducting and a protective layer for AC-plasma display panels to improve discharge characteristics and panel lifetime. Up to now MgO films have been synthesized by lE-beam evaporation, Molecular Beam Epitaxy (MBE) and Metalorganic Chemical Vapor Deposition (MOCVD), however there have been some limitations such as low film density and micro-cracks in films. Therefore magnetron sputtering process were emerged as predominant method to synthesis high density MgO films. In previous works, we designed and manufactured unbalanced magnetron source with high power density for the deposition of high quality MgO films. The magnetron discharges were sustained at the pressure of O.lmtorr with power density of $110W/\textrm{cm}^2$ and the maximum deposition rate was measured at $2.8\mu\textrm{m}/min$ for Cu films. In this study, the syntheses of MgO films were carried out by unbalanced magnetron sputtering with various $O_2$ partial pressure and specially target power densities, duty cycles and frequency using pulsed DC power supply. And also we investigated the plasma states with various $O_2$ partial pressure and pulsed DC conditions by Optical Emission Spectroscopy (OES). In order to confirm the relationships between plasma states and film properties such as microstructure and secondary electron emission coefficient were analyzed by X-Ray Diffraction(XRD), Transmission Electron Microscopy(TEM) and ${\gamma}-Focused$ Ion Beam (${\gamma}-FIB$).

• Journal of the Korean Society for Heat Treatment
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• v.33 no.3
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• pp.129-134
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• 2020

Due to excellent properties such as high specific strength and low density, application of magnesium alloys have been rapidly increased. However, magnesium alloy has a serious problem that is easily oxidized when exposed to high-temperature. For this reason, magnesium alloys have been generally used for SF6 gas such as protective cover gas in casting and melting, but it has been reported that this gas has a serious influence on global warming. Therefore, many researchers have been studied to improve the oxidation resistance of magnesium alloy. It was reported that addition of Be, Ca and CaO in magnesium alloy can improve the oxidation properties. In this study, the possibility of improving the oxidation resistance by adding CaO extracted from oyster shells was investigated. Oyster shells were completely decomposed into CaO and CO₂ by annealing. With the addition of CaO, a coexistence region of MgO + CaO was formed in the oxide layer and its thickness was also reduced.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.364.2-364.2
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• 2014

Magnesium oxide (MgO) thin films have attracted great scientific and technological interest in recent decades. Because of its distinguished properties such as a wide band gap (7.2 eV), a low dielectric constant (9.8), a low refractive index, an excellent chemical, and thermal stability (melting point=$2900^{\circ}C$), it is widely used as inorganic material in diverse areas such as fire resistant construction materials, optical materials, protective layers in plasma display panels, buffer layers of multilayer electronic/photonic devices, and perovskite ferroelectric thin films. Precursor used in the ALD requires volatility, stability, and low deposition temperature. Precursors using a heteroleptic ligands with different reactivity have advantage of selective reaction of the heteroleptic ligands on substrate during ALD process. In this study, we have synethesized new heteroleptic magnesium precursors ${\beta}$-diketonate and aminoalkoxide which have been widely used for the development of precursor because of the excellent volatility, chelating effects by increasing the coordination number of the metal, and advantages to synthesize a single precursor. A newly-synthesized Mg(II) precursor was adopted for growing MgO thin films using ALD.

• Journal of Korea Foundry Society
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• v.34 no.6
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• pp.194-199
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• 2014

The effect of $Al_2Ca$ on the oxidation resistance and tensile property of Al-5Mg alloys was investigated. According to the TGA (Thermogravimetric analysis) result at $550^{\circ}C$ after 24hrs, the Al-5Mg alloy showed parabolic behavior with weight gain. On the other hand, there was almost no difference in the weight changes of the $Al_2Ca$ added Al-5Mg alloys during the oxidation. It was thought that the improvement of oxidation resistance in $Al_2Ca$ added Al-5Mg alloys might be due to the formation of a protective oxide layer with CaO and MgO on the surface. The microstructures of the alloys showed grain refinement with an increasing $Al_2Ca$ content. From the tensile test, the yield strength of the alloys were improved with an increasing $Al_2Ca$ content. The 0.07 mass%$Al_2Ca$ added Al-5Mg alloy showed similar elongation and increased strength, simultaneously. It was considered that the addition of $Al_2Ca$, which was superior in the oxidation resistance of Al, reduced the formation of Mg oxides and inclusions during the alloying. This, partly led to the improvement of tensile properties.