• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.50-50
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• 2011

The aluminum nitride films were prepared by RF magnetron sputtering using an AlN ceramic target. The crystallinity, grain size, Al-N bonding and thermal conductivity were investigated in dependence on the plasma power densities (4.93, 7.40, 9.87 W/$cm^2$) during sputtering. High thermal conductivity is important properties of A1N passivation layer for functioning properly in thermal inkjet printhead. The crytallinity, grain size, Al-N bonding formation and chemical composition were observed using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS), respectively. The AlN thin film was changed from amorphous to crystalline as the power density was increased, and the largest grain size appeared at medium power density. The near stoichiometry Al-N bonding ratio was acquired at medium power density. So, we know that the AlN thin film had better thermal conductivity with crystalline phase and near stoichometry Al-N bonding ratio at 7.40 W/$cm^2$ power density.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.177-179
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• 2011

The purpose of this study is to enhance an adhesion between substrate and Diamond-like Carbon (DLC) film. DLC has many outstanding properties such as low friction, high wear resistance and corrosion resistance. However, it is difficult to achieve enough adhesion because of weak bonding between DLC film and the substrate. For improvement adhesion, a layer between DLC film and the substrate was prepared by dual post plasma. DLC film was deposited on nitrided layer by linear ion source. The composed compound layer between substrate and DLC film was investigated by Glow Discharge Spectrometer (GDS) and Scanning Electron Microscope (SEM). The synthesized bonding structure of DLC film was analyzed using a micro raman spectrometer. Mechanical properties were measured by nano-indentation. In order to clarify the mechanism for improvement in adhesive strength, it was observed by scratch test.

• Journal of Powder Materials
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• v.8 no.1
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• pp.20-25
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• 2001

Most of mold manufacturing procedures have been automated by the introduction of NC machine tool and CAD/CAM system. But the three-dimensional surface curvature of the mold must be done by hand work of well-skilled workers. Magnetic abrasive polishing powders were investigated for surface polishing for 3D curvature. This study aims to investigate homogeneously distributed hard phase in Fe matrix and strong bonding between Fe-matrix and hard phase. The NbC powder, $B_4C$ powder and $Al_2O_3$ powder were mixed in Fe-matrix respectively. Mixed Fe-hard phase powders were compacted by press and then these were melted by plasma melting. According to SEM, XRD and OM observation, Fe-NbC magnetic abrsive powder had the most homogeneous distribution and strong bonding. As a result of magnetic polishing, the surface roughness before magnetic polishing, 1 ${\mu}m$ $R_{max}$, was reduced to 0.2 ${\mu}m$ $R_{max}$ over the entire inner surface of the tube.

• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.335-338
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• 2010

In this study, the atmospheric plasma treatment with $He/O_2$ was conducted to modify the surface chemistry of carbon fibers. The effects of plasma treatment parameters on the surface energetics of carbon fibers were experimentally investigated with respect to gas flow ratio, power intensity, and treatment time. Surface characteristics of the carbon fibers were determined by X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), Fourier transform infrared (FT-IR), Zeta-potential, and contact angle measurements. The results indicated that oxygen plasma treatment led to a large amount of reactive functional groups onto the fiber surface, and these groups can form together as physical intermolecular bonding to improve the surface wettability with a hydrophilic polymer matrix.

• Proceedings of the Materials Research Society of Korea Conference
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• 2006.11a
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• pp.13.1-13.1
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• 2006

• Journal of the Korean Society for Precision Engineering
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• v.24 no.12
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• pp.143-148
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• 2007

Polyethylene is a typical hydrophobic material and it is difficult to bond the polyethylene material with metal material. Thus, it is important to modify the surface of polyethylene material to improve the bonding strength between the polyethylene and the metal materials. In this study, the surface modification of polyethylene material was investigated to improve the interfacial strength between the polyethylene and the steel materials. Polyethylene material was surface-modified in a plasma cleaner using an oxygen gas. Two cases of composites (surface-modified pelyethylene/steel composite and regular (as-received) pelyethylene/steel composite) were fabricated using a secondary bonding method. Shear and bending tests have been performed using the two cases of composites. The results showed that the contact angle did not change much as the modification time increased. However, the contact angle decreased from ${\sim}76^{\circ}\; to\;{\sim}41^{\circ}$ with the modification. The results also showed that the shear strength and the bending strength were improved about 3030 % and 7 %, respectively when the polyethylene was plasma-modified using an oxygen gas.

• Applied Chemistry for Engineering
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• v.32 no.1
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• pp.49-54
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• 2021

Plasma-polymerized methyl methacrylate (MMA) thin films were synthesized by remote plasma, and effects of plasma power, reaction pressure and direct-indirect plasma on the growth rate and chemical bonding were investigated with alpha-step, FT-IR, XPS and Langmüir probe method. As the plasma power and pressure increased, the tendency of growth rate showed maximum value at a certain range. FT-IR and XPS analyses revealed that composition ratio of C/O and hydrocarbon (C-C) % in the deposited films increased with plasma power, but ester (COO) C % decreased with it. Direct plasma method was effective for fast growth rate, but indirect plasma method was favorable for maintaining the chemical structure of MMA.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1061-1065
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• 1995

To improve dielectric and mechanical properties of insulating composite by plasma surface treatment, new plasma surface treatment process is designed with concentric and hemi-circle electrodes system, the plasma, which is generated between anode and cathode, is induced to the upper side of the electrode system and treats the surface of the insulators. The optimal surface treatment condition is that pressure : 0.5[torr], flux density 100[gauss], discharge current : 500[mA] and treatment time : 3 minutes. The composite filled with glass cloth surface-treated by plasma shows the improvement in electric and mechanical properties, comparing non- and coupling agent-treated samples.

• Electrical & Electronic Materials
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• v.8 no.4
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• pp.434-442
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• 1995

To improve dielectric and mechanical properties of insulating composite by plasma surface treatment, new plasma surface treatment process is designed with concentric and hemi-circle electrodes system. the plasma, which is generated between anode and cathode, is induced to the upper side of the electrode system and treats the surface of the insulators. The optimal surface treatment condition is that pressure : 0.5[torr], flux density : 100[gauss], discharge current : 500[mA] and treatment time : 3 minutes. The composite filled with glass cloth surface-treated by plasma shows the improvement in electric and mechanical properties, comparing non- and coupling agent treated samples.

• Journal of the Korean institute of surface engineering
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• v.26 no.2
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• pp.71-81
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• 1993

Thed effects of Ar or Oxygen RF plasma treatment on the adhesion behavior of Cr films to polyimide sub-strates have been investigated by using SEM, XRD, AES, and $90^{\circ}$peel test. By applying RF plasma treatment of the polyimide surface prior to metal deposition, the peel adhesion strength of Cu/Cr films sputtered onto the fully cured BPDA-PDA polyimide was highly increased from about 3g/mm to 90 ~ 100g/mm. Improved peel adhesion strength of Cr/polyimide interfaces due to RF plasma treatment was attributed to the contributions from surface cleaning, Cr-polyimide bonding at the interface, and force required for plastic deformation of the film. While the surface topology change of the polyimide caused by RF plasma treatment makes a little contri-bution to the improved adhesion.