• Corrosion Science and Technology
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• v.3 no.4
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• pp.148-153
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• 2004

Magnesium thin flims were prepared on cold-rolled steel substrates by RF magnetron sputtering technique. The influence of argon gas pressure and substrate bias voltage on their crystal orientation and morphology of the coated films were investigated by scanning electron microscopy (SEM) and X-ray diffraction, respectively. And the effect of crystal orientation and morphology of magnesium films on corrosion behaviors was estimated by measuring anodic polarization curves in deaerated 3%NaCl solution. From the experimental results, all the sputtered magnesium films showed obviously good corrosion resistance to compare with 99.99% magnesium target of the sputter-evaporation metal. Finally it was shown that the Corrosion-resistance of magnesium films can be improved greatly by controlling the crystal orientation and morphology with effective use of the plasma sputtering technique.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.2
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• pp.155-160
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• 2011

In these days, there are increasing demands for weight reduction in many industrial fields including marine industries. Therefore, magnesium thin films for lightweight materials were prepared on magnesium alloy substrate. The influence of gas pressure and substrate bias voltages on the crystal orientation and morphology of the films was determined by using X-ray diffraction and FE-SEM, respectively. And the effect of crystal orientation and morphology of the magnesium thin films on corrosion behavior was estimated by measuring electro-chemical anodic polarization curves in deaerated 3% NaCl solution. From the results, corrosion resistance of Mg thin films was improved by controlling the crystal orientation and morphology of the films with effective use of plasma ion plating technique.

• 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.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.285-286
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• 2006

Magnesium is the lightest of all the structural metals having density of 1.74. It is approximately 2/3 lighter than aluminium, l/4 lighter than titanium alloy and 1/5 lighter than iron. Among the light-weight alloys, magnesium and its alloys show a good possibility for high performance aerospace and automotive applications, however the widespread use of magnesium alloys has been limited mainly by its poor oxidation and corrosion resistance. In this work, corrosion-resistive thin films were prepared onto the magnesium alloy substrate(AZ91D) by environmental friendly coating technique, ion plating method. And their corrosion protection mechanism were analyzed.

• Applied Chemistry for Engineering
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• v.18 no.3
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• pp.262-266
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• 2007

The effect of the presence of magnesium ions in the preparation of calcium phosphate (CP) thin films on the physicochemical and biological properties of the films has been investigated in this study. Five different surfaces were used and the culture plate (CTL) and CP film prepared in the absence of magnesium (CaP) were used for the comparison. Three different films were prepared at different magnesium concentrations. CP films prepared at the Mg concentrations of 0.1, 1, and 10 mM were designated as CaPL, CaPM, and CaPH, respectively. The observation of surface morphology of the CP films using scanning electron microscopy (SEM) displayed that the presence of magnesium affected considerably the morphology of the films including a decrease of surface porosity. X-ray diffraction (XRD) analysis for the determination of the crystallinity of the CP films showed that the structure of the films was amorphous. Examination using X-ray photoelectron spectroscopy (XPS) confirmed the prepared films consisted of calcium, phophorus, and magnesium. Cell adhesion assays elucidated that cell adhered less as the magnesium concentration increased. However, cell proliferation assays demonstrated that the cells proliferated more actively on the films prepared at the higher magnesium concentration. These results suggest that the presence of magnesium may promote the biocompatibility of CP films.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.2
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• pp.252-257
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• 2011

Magnesium thin films for marine engine parts such as the engine block and the cylinder head cover etc. were prepared on the magnesium alloy(AZ91D) substrate by Thermo-electron activated Ion-plating method. The influence of gas pressure and substrate bias voltages on the crystal orientation and morphology of the films was investigated with X-ray diffraction and field emission scanning electron microscope(FE-SEM), respectively. Moreover, the effect of crystal orientation and morphology of the magnesium films on the its hardness property was investigated as well. From the results, the hardness of the films was increased in Ar gas pressure due to the grain boundary strengthening and occlusion effects.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.19-27
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• 2003

Morphology and composition of MgO films grown on single-crystalline diamond (100) have been studied. MgO thin films were deposited in the substrate temperature range from room temperature (RT) to 723K by means of electron beam evaporation using MgO powder source. Atomic force microscopy images indicated that the film grown at RT without $O_2$ supply was relatively uniform and flat whereas that deposited in oxygen ambient yielded higher growth rates and rough surface morphologies. X-ray photoelectron spectroscopy analyses demonstrate that the MgO film deposited at RT without $O_2$ has the closest composition to the stoichiometric MgO, and that a thin contaminant layer composed mainly of magnesium peroxide (before etching) or hydroxide (after etching) was unintentionally formed on the film surface, respectively. These results will be discussed in relation to the interaction among the evaporated species and intentionally supplied oxygen molecules at the growth front as well as the interfacial energy between diamond and MgO.

• Transactions on Electrical and Electronic Materials
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• v.8 no.4
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• pp.153-156
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• 2007

Structural and electrical properties of the fully crystallized-bismuth magnesium niobate ($Bi_2Mg_{2/3}Nb_{4/3}O_7$, BMN) films with 15 mol% excess bismuth deposited on Pt bottom electrode by pulsed laser deposition are characterized for various deposition temperatures. The BMN films were crystallized with a monoclinic structure from $300^{\circ}C$ and the surface roughness slightly decreases with increasing deposition temperature. The capacitance density of the films increases with increasing deposition temperature and especially, films deposited at $400^{\circ}C$ exhibit a capacitance density of approximately $620nF/cm^2$. The crystallized BMN films with approximately 170 nm thickness exhibit breakdown strength above 600 kV/cm (${\leq}10V$) irrespective of deposition temperature and a leakage current density of approximately $2{\times}10^{-8}A/cm^2$ at 590kV/cm (at 10 V).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.264-264
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• 2007

$B_2Mg_{2/3}/Nb_{4/3}O_7\;(B_2MN)$ thin films and $Bi_{3/2}MgNb_{3/2}O_7\;(B_{1.5}MN)$ thin films were deposited as a function of various deposition temperatures on Pt/$TiO_2/SiO_2$/Si substrates by radio frequency magnetron sputtering system. Both of their thin films are shown to crystalline phase at $500^{\circ}C$, deposition temperature, using 100W RF power. The composition of them and structural micro properties are investigated by RBS spectrum and SEM, AFM. 200 nm-thick $B_2MN$ thin films were deposited at room temperature had capacitance density of $151nF/cm^2$ at 100kHz, dissipation factor of 0.003 and had capacitance density of $584nF/cm^2$ at 100kHz, dissipation factor of 0.0045 at $500^{\circ}C$ deposition temperature. Both of their dielectric constant deposited at room temperature and at $500^{\circ}C$ were each approximately 40 and 100.

• Journal of Advanced Marine Engineering and Technology
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• v.20 no.5
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• pp.103-113
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• 1996

The properties of the deposited film depend on the deposition condition and these, in turn depend critically on the morphology and crystal orientation of the films. Therefore, it is important to clarify the nucleation occurrence and growth stage of the morphology and orientation of the film affected by deposition parameters, e.g. the gas pressure and bias voltage etc. In this work, magnesium thin flims were prepared on cold-rolled steel substrates by a thermo-eletron activation ion plating technique. The influence of nitrogen gas pressure and substrate bias voltage on their crystal orientation and morphology of the coated films were investigated by scanning electron microscopy (SEM) and X-ray diffraction, respectively. The diffraction peaks of magnesium film became less sharp and broadened with the increase of nitrogen gas pressure. With an increase in nitrogen gas pressure, flim morphology changed from colum nar to granular structure, and surface crystal grain-size decreased. The morphology of films depended not only on gas pressure but also on bias voltage, i.e., the effect of increasing bias voltage was similar to that of decreasing gas pressure. The effect of crystal orientation and morphology of magnesium films on corrosion behaviors was estimated by measuring anodic polarization curves in deaerated 3%NaCl solution. Magnesium, in general, has not a good corrosion resistance in all environments. However, these magnesium films prepared by changing nitrogen gas pressure showed good corrosion resistance. Among the films, magnesium films which exhibited granular structure had the highest corrosion resistance. The above phenomena can be explained by applying the effects of adsorption, occlusion and ion sputter of nitrogen gas.