• 대한기계학회논문집A
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• 제38권6호
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• pp.629-636
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• 2014

비정질합금이 가지고 있는 우수한 기계적 성질과 화학적 특성을 부품소재에 표면개질을 목적으로 고속화염 용사법으로 대면적 코팅층을 형성하였고 내열성이 높은 자융성합금과 초경합금 성분들을 적절히 혼합하여 비정질기지 복합재료를 제조하여 코팅들의 미세조직 관찰과 나노인덴테이션을 이용한 미세표면의 기계적 거동을 분석하였다. 각 코팅층의 미세조직을 관찰한 결과, 단일상 비정질 코팅에는 미용융 입자와 lamellae 영역이 존재하고 자융성합금이 고용된 복합재에는 in-situ $Cr_2Ni_3$ 석출물, 자융성합금과 초경합금성분이 함께 혼합된 코팅층은 석출물과 ex-situ WC 강화입자가 공존하였다. 이들 미세표면의 기계적 거동은 제 2 상이 고용된 비정질 기지 복합재의 코팅층의 기계적 특성이 전체적으로 향상되었다.

• 한국산학기술학회논문지
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• 제16권11호
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• pp.7667-7671
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• 2015

아연말 코팅은 친환경성 및 고성능으로 인하여 널리 사용되고 있다. 일반적으로 코팅온도가 코팅층 두께 및 코팅품질을 결정하는 주요한 요소이므로 아연말 코팅의 경우에도 최적의 코팅온도가 요구되고 있다. 본 연구에서는 아연말 스프레이 코팅 룸의 온도분포를 해석하기 위해 룸 내부의 공기유동을 포함하는 열 유동 전산 시뮬레이션을 수행하였다. 3차원 CAD 프로그램인 SolidWorks를 이용하여 스프레이 코팅 룸 전체와 예열실과 건조실을 모두 고려한 모델링을 수행하였으며 Flow Simulation 프로그램을 이용하여 열 유동 해석을 수행하였다. 해석된 결과는 열화상카메라를 이용한 실험으로 검증하였다. 해석결과 제1스프레이실과 제2스프레이실의 온도분포 특성을 파악할 수 있었으며, 현재의 상태로는 목표 온도 값인 $25^{\circ}C$에 미달하고 있었음을 알 수 있었다. 단순히 히터를 추가하는 방법 대신, 현재 조건에서 스프레이실의 온도를 높이는 방안으로 배기팬을 사용하지 않는 경우에 대해 시뮬레이션을 수행하였으며, 그 결과 제1스프레이실의 온도가 $6.2^{\circ}C$, 제2스프레이실의 온도가 $5.8^{\circ}C$ 상승하였다. 본 연구 내용은 향후 스프레이 코팅 룸의 성능향상을 위한 설계에 이용될 수 있다.

• Elastomers and Composites
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• 제50권2호
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• pp.98-102
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• 2015

A series of polyurethane-acrylate hybrids were synthesized by 2-step emulsion polymerization of a variety of acrylate monomers such as 2-hydroxy ethyl methacrylate (HEMA), methyl methacrylate (MMA). Experiment was performed to improve stability and emulsibility of surface treatment agent, and it was found that the polyurethane-acrylate hybrids having an optimum composition (MMA : 20%, LA(EO)3-S : 3% and TDA-7 : 5%) was shown to be quite surface active in the solid contents. These results suggests that the optimal polyurethane-acrylate hybrids in this study have high potential as top coating agent, which may have high gloss and excellent properties.

• 한국광학회:학술대회논문집
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• 한국광학회 1989년도 제4회 파동 및 레이저 학술발표회 4th Conference on Waves and lasers 논문집 - 한국광학회
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• pp.49-54
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• 1989

Thin solid film systems polarizing beam splitter and disk amplifier used in the high power laser system ({{{{ lambda }}0=1060nm) are designed by computer aided optimization technique. Extinction ratio of designed polarizing beam splitter for incidence angle 30$^{\circ}$, 45$^{\circ}$, 55.60$^{\circ}$ are 1:93, 1:895, 1:1991. respectively. Maximum reflectance of designed thin film system of disk amplifier is less than 3% for pumping band (500-900nm) and 0.15% for laser beam. Further, SiO film chosen as one of the suitable thin films in the high power laser system is prepared by the sol=-gel process which gives high damage threshold. When the withdrawal speed is 6.15cm/min -16.62 cm/min and the mixing ratio is in the range of 1 mol (ethylsilicate): 4-8mol(ethylalcohol) : 2mol(water), the thickness of deposited film is in the range of 500{{{{ ANGSTROM }}-1500{{{{ ANGSTROM }}.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제28회 추계학술대회
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• pp.221-226
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• 1998

The processing conditions for the mass production of platelet WS$_2$ lubricant powder were optimized. The mixture of tungsten and sulfur powders was sealed in a vacuum of 10$^{-3}$ torr and heat-treated at 850$\circ$C for 2 h. The internal pressure of reaction chamber was maintained at certain level by controlling the release valve automatically. The reaction product was the platelet WS$_2$ powder with an average size of 15 $\mu$m. The synthesized WS$_2$ powder was then coated on the wiper-blade of automobiles and the commercial deep-grooved ball bearing using wet and dry coating methods, respectively. High lubricity and wear resistance of wet coated wiper-blade were confirmed by the life test of 70,000 cycles. The life-time of the ball bearing assembled after WS$_2$ coating onto each part increased 50 times compared to the non-coated ball bearing.

• 펄프종이기술
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• 제32권3호
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• pp.32-38
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• 2000

This study was carried out to determine the effect of the type of plastic pigment on the coat-ing structure and printability of coated paper. Three kinds of plastic pigments(solid-bead type binder type and hollow type) were used for hti purpose. IN this research it was observed that particle shape and structure of plastic pigment had influenced the rheology of coating color the state of packing and the properties of coated paper. Inorganic pigments used in this research were platelike kaolin clay and rhombic calcium carbonate. Three kinds of plastic pigments were blended with two inorganic pigments respec-tively. The combination of pigments were carried out(1) to determined the effect of particle structure of plastic pigment on the state of dispersion of coating color(2) to observe the effect of calendering temperature on the property of coated paper prepared with different plastic pigments. The data indicated that binder and hollow type plastic pigment gave the best results in improving the properties of coated paper such as paper gloss opacity and air pet-meability.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.236-237
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• 2006

Cold spraying is a fairly new coating technique, which within the last decade attracted serious attention of research groups and spray companies. As compared to thermal spraying, the low process temperatures in cold spraying result in unique coating properties, which promise new applications. Since particles impact with high kinetic energy in the solid state, new concepts to describe coating formation are requested to enable the full potential of this new technology. The present contribution gives a brief review of current models concerning bonding, supplying a description of the most influential spray parameters and consequences for new developments. With respect to spray forming by cold cold spraying, microstructures and thick, further machineable structures are presented.

• 열처리공학회지
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• 제8권1호
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• pp.3-11
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• 1995

A theoretical model which combines gaseous transport and solid state diffusion was used to study aluminide coating process by pack cementation. The aluminide coatings were applied in the high activity pack containing $NH_4Cl$ activator with Ni substrate under argon atmosphere. On the basis of the process conditions, the suggested model allows the surface composition, the growth rate of coating layers and the aluminium concentration profiles in coatings to be calculated. In the case of $NH_4Cl$ activator, careful consideration was required in the analysis, because activator contains nitrogen and hydrogen as well as halogen element to activate the pack. A good agreement is obtained between the theoretical predictions and the experimental results.

• 센서학회지
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• 제15권3호
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• pp.153-157
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• 2006

This paper presents the method for three-dimensional micro structure with photoresist spray coating system. The system consists of a high temperature rotational chuck, ultrasonic spray nozzle module, angle control module and nozzle moving module. Spray coating system is effected by several parameters such as the solid contents, the dispensed volume, the scanning speed of the spray nozzle and the wafer of dimension. The photoresist (AZ 1512) has been coated on the three-dimensional micro structure by spray coating system and the characteristics have been evaluated.

• 한국세라믹학회지
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• 제36권9호
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• pp.982-990
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• 1999

YSZ/LSM composite cathode was fabricated by dip-coating of YSZ sol on the internal pore surface of a LSM cathode followed by sintering at low temperature (800-100$0^{\circ}C$) The YSZ coating significantly increased the TPB(Triple Phase Boundary) where the gas the electrode and the electrolyte were in contact with each other. Sinter the formation of resistive materials such as La2Zr2O7 or SrZrO3 was prevented due to the low processing temperature and TPB was increased due to the YSZ film coating the electrode resistance (Rel) was reduced about 100 times compared to non-modified cathode. From the analysis of a.c impedance it was shown that microstructural change of the cathode caused by YSZ film coating affected the oxygen reduction reaction. In the case of non-modified cathode the RDS (rate determining step) was electrode reactions rather than mass transfer or the oxygen gas diffusion in the experimental conditions employed in this study ($600^{\circ}C$-100$0^{\circ}C$ and 0,01-1 atm of Po2) for the YSZ film coated cathode however the RDS involved the oxygen diffusion through micropores of YSZ film at high temperature of 950-100$0^{\circ}C$ and low oxygen partial pressure of 0.01-0.03 atm.