• Korean Journal of Metals and Materials
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• v.50 no.7
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• pp.539-544
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• 2012

Thermal shock behavior of TiN-coated SUS 304 substrate was investigated using a laser ablation method. By short surface ablation with a pulse Nd-YAG laser, considerable surface crack and spalling were observed, whereas there were few oxidation phenomena, such as grain growth of TiN crystallites, nucleation and growth of $TiO_2$ crystallites, which were observed from the coatings quenched from $700^{\circ}C$ in a chamber. The oxygen concentration of the ablated coating surface with the pulse laser also had a lower value than that of the quenched coating surface by Auger electron spectroscopy and electron probe micro analysis. These results were attributed to the fact that the properties of the pulse laser method have a very short heating time and so the diffusion time for oxidation was insufficient. Consequently, it was verified that the laser thermal shock test provides a way to evaluate the influence of the thermal shock load reduced oxidation effect.

• Progress in Superconductivity and Cryogenics
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• v.12 no.4
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• pp.17-19
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• 2010

In this work, the optimized process condition of chemical solution deposition which is used to planarize the surface of the metal tape (which is used to grow IBAD-MgO texture template) was investigated. $Y_2O_3$ films were dip-coated on the surface of the unpolished metal tape as the seed and barrier layer. The effects of $Y_2O_3$ concentration of the solution (0.5wt.%, 1.3wt.%, 2.8wt.%, 5.6wt.%) and the number of coatings on the surface morphology and barrier capability against the diffusion from the metal tape were examined. The surface morphology and the thickness of the film were observed using the scanning electron microscope and the atomic force microscope. The presence of elements in metal tape on the film surface was analyzed using the auger electron spectroscopy. The $Y_2O_3$ film thickness increases with increasing the $Y_2O_3$ concentration in the solution, and the surface became smoother with increasing the number of coating cycles. The best result was obtained from the $Y_2O_3$ film coated 4 cycles using 2.8wt.% solution.

• Nuclear Engineering and Technology
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• v.51 no.8
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• pp.1983-1990
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• 2019

Spray deposited Molybdenum trioxide (MoO₃) thin film of thickness nearly 379 nm were irradiated with 200 MeV Ag¹⁵⁺ ion beam at different fluences (Ø) of 5 ×10¹¹, 1 × 10¹², 5 × 10¹² and 1 × 10¹³ ions/㎠. The X-ray diffraction (XRD) pattern of the pristine film confirms orthorhombic structure and the crystallinity decreased after irradiation with the fluence of 5 × 10¹¹ ions/㎠ due to irradiation induced defects and became amorphous at higher fluence. In pristine film, Raman modes at 665, 820, 996 cm^-1 belong to Mo-O stretching, 286 cm^-1 belong to Mo-O bending mode and those below 200 cm^-1 are associated with lattice modes. Raman peak intensities decreased upon irradiation and vanished completely for the ion fluence of 5 ×10¹² ions/㎠. The percentage of optical transmittance of pristine film was nearly 40%, while for irradiated films it decreased significantly. Red shift was observed for both the direct and indirect band gaps. The pristine film surface had densely packed rod like structures with relatively less porosity. Surface roughness decreased significantly after irradiation. The electrical transport properties were also studied for both the pristine and irradiated films by Hall effect. The results are discussed.

• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.771-777
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• 1999

The structural function of three egg membrane layers and cuticle layer, and the effectiveness of 5 film coatings (chitosan, starch, gelatin, dextrin, mineral oil) on the prevention of Salmonella enteritidis penetration was investigated using confocal scanning laser microscopy (CSLM). Diameters of outer membrane fibers, inner membrane fibers and limiting membrane particles in eggshell were $1.5{\sim}7.2$, $0.8{\sim}2.0$ and $0.1{\sim}1.4\;{\mu}m$, respectively and average thicknesses were 10.0, 3.5, $3.6\;{\mu}m$, respectively. Average thickness of cuticle layer was $6.0\;{\mu}m$ and cuticle layer covered $40{\sim}80%$ of total eggshell surface. Average coating films thickness for chitosan, starch, gelatin, dextrin and mineral oil were 2.2, 2.5, 3.9, 3.6 and $5.0\;{\mu}m$, respectively. After immersion process eggshell surface was almost completely covered by coating films. Chitosan coating was most effective among 5 film coatings in inhibiting growth of Salmonella enteritidis. Penetration process of Salmonella enteritidis through eggshell was investigated by multicolor imaging using CSLM and plate counting. Cuticle layer was the most important structure in blocking the penetration. Among 5 film coatings, chitosan showed the best and similar effectiveness with cuticle layer.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.4
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• pp.263-266
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• 2017

In this study, the characteristics of anti-pollution coatings on glass substrates through annealing treatment were investigated. To investigate the change of properties by coating method and number of annealing treatment, after the anti-pollution coating was performed on the surface of glass substrate in three ways, the annealing treatment was performed by setting three kinds of annealing treatment conditions. The annealing treatment method is a torch using gas, which is advantage in that it can be installed directly on the site in an easy way compared with a annealing treatment process which is generally difficult. The anti-pollution properties, contact angle, transmittance, hardness, and adhesion of films on glass substrate were measured under 9 conditions of combination of coating methods and annealing treatment conditions. It was confirmed that as the number of annealing treatment increases, the anti-pollution property of the film synthesized on glass substrate becomes better.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.5
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• pp.475-480
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• 2015

Ultrasonic atomic force microscopy (Ultrasonic-AFM) has been used to investigate the elastic property of the ultra-thin coating layer in a thin-film system. The modified Hertzian theory was applied to predict the contact resonance frequency through accurate theoretical analysis of the dynamic characteristics of the cantilever. We coat 200 nm thick Aluminum and Titanium thin films on the substrate using the DC Magnetron sputtering method. The amplitude and phase of the contact resonance frequency of a vibrating cantilever varies in response to the local stiffness constant. Ultrasonic-AFM images were obtained using the variations in the elastic property of the materials. The morphology of the surface was clearly observed in the Ultrasonic-AFM images, but was barely visible in the topography. This research demonstrates that Ultrasonic-AFM is a promising technique for visualizing the distribution of local stiffness in the nano-scale thin coatings.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.1
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• pp.61-66
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• 2022

This study is to increase the surface area and maximize the effect of the catalyst by coating a nanometersized metal catalyst material on the anode layer using atomic layer deposition (ALD) technology. ALD process is known to produce uniform films with well-controlled thickness at the atomic level on substrates. We measured the performance by coating metals (Ni) on Ni/YSZ, which is the most widely known anode material for solid oxide fuel cells. ALD coatings began to show a decrease in cell performance over 3 nm coatings.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2000.11a
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• pp.3-4
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• 2000

Many researchers are interested in the synthesis and characterization of carbon nitride and diamond-like carbon (DLq because they show excellent mechanical properties such as low friction and high wear resistance and excellent electrical properties such as controllable electical resistivity and good field electron emission. We have deposited amorphous carbon nitride (a-C:N) thin films and DLC thin films by shielded arc ion plating (SAIP) and evaluated the structural and tribological properties. The application of appropriate negative bias on substrates is effective to increase the film hardness and wear resistance. This paper reports on the deposition and tribological OLC films in relation to the substrate bias voltage (Vs). films are compared with those of the OLC films. A high purity sintered graphite target was mounted on a cathode as a carbon source. Nitrogen or argon was introduced into a deposition chamber through each mass flow controller. After the initiation of an arc plasma at 60 A and 1 Pa, the target surface was heated and evaporated by the plasma. Carbon atoms and clusters evaporated from the target were ionized partially and reacted with activated nitrogen species, and a carbon nitride film was deposited onto a Si (100) substrate when we used nitrogen as a reactant gas. The surface of the growing film also reacted with activated nitrogen species. Carbon macropartic1es (0.1 -100 maicro-m) evaporated from the target at the same time were not ionized and did not react fully with nitrogen species. These macroparticles interfered with the formation of the carbon nitride film. Therefore we set a shielding plate made of stainless steel between the target and the substrate to trap the macropartic1es. This shielding method is very effective to prepare smooth a-CN films. We, therefore, call this method "shielded arc ion plating (SAIP)". For the deposition of DLC films we used argon instead of nitrogen. Films of about 150 nm in thickness were deposited onto Si substrates. Their structures, chemical compositions and chemical bonding states were analyzed by using X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and infrared spectroscopy. Hardness of the films was measured with a nanointender interfaced with an atomic force microscope (AFM). A Berkovich-type diamond tip whose radius was less than 100 nm was used for the measurement. A force-displacement curve of each film was measured at a peak load force of 250 maicro-N. Load, hold and unload times for each indentation were 2.5, 0 and 2.5 s, respectively. Hardness of each film was determined from five force-displacement curves. Wear resistance of the films was analyzed as follows. First, each film surface was scanned with the diamond tip at a constant load force of 20 maicro-N. The tip scanning was repeated 30 times in a 1 urn-square region with 512 lines at a scanning rate of 2 um/ s. After this tip-scanning, the film surface was observed in the AFM mode at a constant force of 5 maicro-N with the same Berkovich-type tip. The hardness of a-CN films was less dependent on Vs. The hardness of the film deposited at Vs=O V in a nitrogen plasma was about 10 GPa and almost similar to that of Si. It slightly increased to 12 - 15 GPa when a bias voltage of -100 - -500 V was applied to the substrate with showing its maximum at Vs=-300 V. The film deposited at Vs=O V was least wear resistant which was consistent with its lowest hardness. The biased films became more wear resistant. Particularly the film deposited at Vs=-300 V showed remarkable wear resistance. Its wear depth was too shallow to be measured with AFM. On the other hand, the DLC film, deposited at Vs=-l00 V in an argon plasma, whose hardness was 35 GPa was obviously worn under the same wear test conditions. The a-C:N films show higher wear resistance than DLC films and are useful for wear resistant coatings on various mechanical and electronic parts.nic parts.

• Korean Journal of Food Science and Technology
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• v.28 no.1
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• pp.1-7
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• 1996

Three formulations were used to prepare the cellulose-based edible films consisting of hydrocolloid and lipids; film A made by coating method, films B and C by emulsion method, which were formed in a thin layer glass plate and then dried. Films A, B and C were all approximately 0.03 mm thick with 1-3% moisture, 59-68% lipid, and almost whitish color. Film A was better in tensile strength, and lipids affected water vapor permeability on three films, in which films A and B did not differ significantly. Water vapor permeability of film A did not change but those of films B and C decreased significantly after storage for 8 weeks at $-15^{\circ}C$. Oxygen transmission rate and oxygen permeability of films A and C did not differ and changed significantly after 8-week storage at $-15^{\circ}C$. Under scanning electron microscope (SEM) observation on the structural characteristics of each film, film A indicated relatively uniform and smooth surface coatings of beeswax, while films B and C had individual lipid crystals and could be discerned. As a result, film A was better than films B and C in respect of physical properties, but the selection of useful film depended upon which physical property was more functional. Moreover, it was desirable in some cases for using films B and C because of their easiness of preparation and cold storage durability. It will be further needed to investigate how to formulate films B and C to have more unique surface characteristics, and to reduce water vapor and oxygen transmission rates.

• Transactions on Electrical and Electronic Materials
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• v.1 no.4
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• pp.11-15
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• 2000

This paper presents a process optimization of antireflection (AR) coating on crystalline Si solar cells. Theoretical and experimental investigations were performed on a double-layer AR(DLAR) coating of MgFe$_2$/GeO$_2$. We investigated GeO$_2$ films as an AR layer because they have a proper refractive index of 2.46 and demonstrate the same lattice constant as Si substrate. RF sputter grown GeO$_2$ film showed deposition temperature strong dependence. The GeO$_2$ at 400$\^{C}$ exhibited a strong (111) preferred orientation and the lowest surface roughness of 6.87 $\AA$. Refractive index of MgFe$_2$film was measured as 1.386 for the most of growth temperature. An optimized DLAR coating showed a reflectance as low as 2.04% in the wavelengths ranged from 0.4 ㎛ to 1.1 ㎛. Solar cells with a structure of MgFe$_2$/GeO$_2$/Ag/N$\^$+//p-type Si/P$\^$+//Al were investigated with the without DLAR coatings. We achieved the efficiency of solar cells greater than 15% with 3.12% improvement with DLAR coatings. Further details about MgFe$_2$,GeO$_2$ films, and cell fabrication parameters are presented in this paper.