• 대한기계학회논문집
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• 제19권3호
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• pp.705-712
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• 1995

The wear characteristics and wear mechanisms in TiN coating deposited on high speed steel and alloy tool steel by ion plating were investigated. Pin on V-block wear tester was used for a wear test method. The specimen was composed of three kinds of high speed steel and alloy tool steel which had different hardness by changing the heat treating condition. Three kinds of coating thickness were also applied to each specimen. Microscopic observation of worn surfaces was made by SEM. The scratch test of coating surface by the ion plating showed that critical load to break the coating interface was greater than 50N. The critical load increased with both substrate hardness and coating thickness. The wear resistance of TiN coated high speed steel became 10 times greater than that of non-coated ones. SEM observation showed that leading edge of contact was compressive and trailing edge was under maximum tensile stress and then surface cracking broke out perpendicular to sliding direction.

• Steel and Composite Structures
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• 제23권2호
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• pp.153-160
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• 2017

It is extremely important to be aware of the ballistic performances of engineering materials in order to be able to choose the lightest armor providing full ballistic protection in civil and military applications. Therefore, ballistic tests are an important part of armor design process. In this study, ballistic performance of plates made of carbon steel and cold worked tool steel against 7.62 mm AP (armor-piercing) bullets was examined experimentally and numerically in accordance with NIJ standards. Samples in different sizes were prepared to demonstrate the effect of target thickness on ballistic performance. Some of these samples were coated with titanium nitride using physical vapor deposition (PVD) method. After examining all successful and unsuccessful samples at macro and micro levels, factors affecting ballistic performance were determined. Explicit non-linear analyses were made using Ls-Dyna software in order to confirm physical ballistic test results. It was observed that the ballistic features of steel plates used in simulations comply with actual physical test results.

• Structural Engineering and Mechanics
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• 제61권4호
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• pp.519-526
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• 2017

In the present paper, the effects of cutting parameters and coating material on the performances of cutting tools in turning of AISI 52100 steel are discussed experimentally. A comparative study was carried out between uncoated and coated (with TiCN-TiN coating layer) cermet tools. The substrate composition and the geometry of the inserts compared were the same. A mathematical model was developed based on the Response Surface Methodology (RSM). ANOVA method was used to quantify the effect of cutting parameters on the machining surface quality and the cutting forces. The results show that feed rate has the most effect on surface quality. However, cutting depth has the significant effect on the cutting force components. The effect of coating layers on the surface quality was also studied. A lower surface roughness was observed when using PVD (TiCN-TiN) coated insert. A second order regression model was developed and a good accuracy was obtained with correlation coefficients in the range of 95% to 97%.

• 연구논문집
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• 통권26호
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• pp.121-132
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• 1996

The carburising surface modification treatment of the die steel has been used for improving wear resistance and heat cycle strength of the die and preventing a pitting on the surface because the carbides are forming in the matrix during carburising. Generally, the hot forging die was used after quenching-tempering treatment or nitriding after quenching-tempering treatment. The nitriding after carburising on the surface of a hot die steel and a wear resistance die steels was suggested by SOUCHARD, JACQUOT. and BUVRON. This surface modification treatment improved the adhesive and abrasive wear resistance and friction coefficient. The process was introduced to the forging die of stainless steel, titanium alloy steel, alloy and medium carbon steel and the physical properties of the die after the treatment were improved. The surface hardening treatment of the nitriding, the carburising, the boriding, and TD process were used to improved the life time of the forging die. Also, the coating process of PVD, CVD and PCVD were used and the hard chromium plating was occasionally used. Therefore, this study analyzed the effects of the carburising time and the conditions of nitriding on STD61 steel. The case depth, the surface hardness, the forming carbide size and shape during overcarburising process on the die steel were also examined.

• 한국기계가공학회지
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• 제18권12호
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• pp.45-51
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• 2019

As the separator becomes thinner, the role of thermal stability becomes more important in ensuring the high capacity of medium- and large-sized lithium-ion secondary batteries. In this study, we researched coating technology to improve the separator's thermal stability. We minimized the coating time by optimizing the design of a vertical two-stage coater that was thin, uniform, and capable of coating on both sides at the same time with a maximum 2㎛ thickness coating layer of fluorinated polymer (PVdF-HFP) on the bare polyethylene (PE) separator, which increased the thermal stability. In addition, during the coating process, a dual-jacket-roll method of drying was developed that increased the drying effectiveness without thermal damage to the separator. We also investigated the thermal stability of the separator manufactured from a coating machine, and studied the battery-applied performance by making a lithium-ion pouch battery.

• 한국표면공학회지
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• 제28권6호
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• pp.368-375
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• 1995

Thermal CVD method is in general used for the fabrication of TiC/$Al_2O_3$-coated carbide tools. The growth of TiC layer and the coating morphology depended on the chemical composition of the hard metal substrate on which the tool properties were strongly influenced. TiC-coated layer was grown by the diffusion of carbon from the substrate, whereas the growth of $Al_2O_3$ layer was unrelated to the composition of substrate. In the nitride hard coatings of Zr, Nb and Mo metals deposited on high speed steel substrate by magnetron sputtering, the reactivity of the metal elements was decreased with increasing group number in one period of the periodic system. The hard material films exhibited the highest adhesion with the chemical composition of stoichiometry or substoichiometry. The critical load as a measure of adhesion was evaluated using scratch tester. The CVD tools indicated the values of 80 and 40N in the coated layers with proper bonding to the substrate and with $\eta$ phase of 1$\mu\textrm{m}$ in the interface respectively, but the nitride films prepared by sputtering of PVD showed only the values between 10 and 20N.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 하계학술대회 논문집
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• pp.183-186
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• 1990

The lattice mismatch between ZnS and Si is negligible because of its value being 0.39%. In this study, $ZnS/_{(P)}Si$ solar cell were fabricated as a layer of ZnS is epitaxially grown on a silicon substrate by PVD method and its photovoltaic properties were measured and discussed. The heat treatment was done after deposition. As the temperature increased up to a certain value, the film has better perfection in crystal structure and electrical characteristics. Measurments of the change that occur in the ZnS films were made by SEM., X-ray diffraction. The optimal thickness of film showned $0.6{\mu}m$, being measured by SEM. The great improvement of the grain growth ZnS film came out after heat-treatment. The result obtained from the $ZnS/_{(P)}Si$ solar cell as follows:short circuit current; $I_{sc}=54mA/cm^2$,open voltage; $V_{oc}=400mV$, fill factor FF=0.72, conversion efficiency; ${\eta}=15.6%$ under the irradiation of 100 ($mW/cm^2$) focused by solar energy. And these are discussed in comparison with other kinds.

• 한국정밀공학회지
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• 제20권12호
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• pp.126-134
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• 2003

In order to investigate the effect of surface treatment in Aluminium alloy and Titanium alloy which are used to armor material during ballistic impact, a ballistic testing was conducted. Anodizing was used to achieve higher surface hardness of Aluminium alloy and Iron plating in PVD(Physical Vapor Deposition) method was used to achieve higher surface hardness of Titanium alloy. Surface hardness test were conducted using a Micro victor's hardness tester. Ballistic resistance of these materials was measured by protection ballistic limit(V-50), a statical velocity with 50% probability penetration. Fracture behaviors and ballistic tolerance, described by penetration modes, are respectfully observed from the results of V-50 test and Projectile Through Plates (PTP) test at velocities greater than V-50. PTP tests were conducted with 0$^{\circ}$obliquity at room temperature using 5.56mm ball projectile. V-50 tests were conducted with 0$^{\circ}$obliquity at room temperature with projectiles that were able to achieve near or complete penetration during PTP tests. Surface hardness, resistance to penetration. and penetration modes of surface treated alloy laminates are compared to those of surface non-treated alloy laminates. A high speed photography was used to analyze the dynamic perforation phenomena of the test materials.

• 한국표면공학회지
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• 제24권3호
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• pp.119-124
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• 1991

Recently, the trend of research in hard coating is concentrate on developing the process of ionization rate under low operating pressure, to get the thin film with high adhesion and dense microstructures. In this study ionization rate enhancement type PVD process using permanent magnet is developed, which enhances the ionization rate by confining the plasma suppressing the wall loss of electron. By the result to investigate the characteristic of glow discharge, the ionization rate of this process is enhanced about twice as high as that of triod BARE process (about 26%), and more dense TiN microstructures are obtained in this process. Cylindrical ion energy analyzer is made and attached in front of a quadrupole mass filter for the analysis of the energy distribution of reactive gas and activated gas ions from the plasma zone. To analyze the operation mechanism of ion energy analyzer, computer simulation is performed by calculation the electric field environment using finite element method. By these analyses of ion energy distribution of outcoming ions from the plasma zone, it is found that magnetic field enhances ion kinetic energy as well as ionization rate. The other results of this study is that the foundation of feed-back system is constructed, which automatically control the partial pressure of reactive gas. In can be possible by recording the data of mass spectrum and ion energy analysis using A-D converter.

• 한국인쇄학회지
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• 제24권2호
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• pp.49-59
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• 2006

In this paper, a transparent film exposed the effect of heat cut-off, reveal as means of the prevention to wrong operation of parts of display and forgery of the credit card, also it will intercept rising of the temperature in interior of a room and car by diminish the influx of near-infrared ray wavelength of solar energy come from the window. As in the past a film which absorb a wavelength of $800{\sim}2500nm$ in near-infrared ray, manufactured in physical vapor deposition(PVD), chemical vapor deposition(CVD) to using ATO, ITO of inorganic materials or sputtering method. but it has lots of problem in manufacture. On the other hand, recently a paper said it easily form a transparent film to using organic dye. This paper show synthesis of many derivatives used in Ni-complex and then it investigate to optical property and durability of flim by make the transparent film.