• Title/Summary/Keyword: spray-layer-by-layer process

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Effects of the Nanometer-sized Bismuth Oxide Coating on Shadow Mask

  • Kim, Sang-Mun;Koh, Nam-Je
    • Journal of Information Display
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    • v.6 no.4
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    • pp.40-44
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    • 2005
  • Nanometer-sized bismuth oxide with a diameter of about 80 nm was used as a new electron reflection material in a 29" Real Flat CPT. This bismuth oxide was well dispersed over pH8 in slurry. Spray coating was performed clearly and uniformly and was ensured that there was no clogging of shadow mask hole. Coating thickness was expressed to the brightness of chromaticity for the sprayed layer and was also well controlled during the spraying process. Doming was improved by about 10% in spite of the similar coating weight in comparison with the average 3.5 ${\mu}m$ of the conventional bismuth oxide.

Effect of Heat Treatment of powder on the Tribological Behavior of the Plasma Sprayed Zirconia Coating (분말 열처리가 지르코니아 용사코팅층의 마모특성에 미치는 영향)

  • 신종한;임대순;안효석
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2000.11a
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    • pp.298-303
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    • 2000
  • The 3 mol% yttria stabilized zirconia (3-Y PSZ) powder was heat treated at 50 0$^{\circ}C$ to evaporate the polymer binder and stabilize the tetragonal phase. The wear experiments were carried out on a ring-on-plate type reciprocating wear tester at selected temperatures with in the range room temperature to 600$^{\circ}C$ The results show that the heat treatment of powder decreases the wear rate due to the reduction of microcracks and pores in coatings and the stabilization of the tetragonal phase. Powder heat treatment enhanced the quality of the coating layer by removing remnant gases during coating process and the powder heat treatment at which tetragonal phase is stable diminished phase ratio of monoclinic. These two effects improved wear resistance characters.

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Hot Corrosion Behavior of Plasma-Sprayed Partially Stabilized Zirconia Coatings in a Lithium Molten Salt (리튬용융염에서 플라즈마 용사된 부분안정화 지르코니아 코팅층의 고온부식 거동)

  • Cho, Soo-Haeng;Hong, Sun-Seok;Kang, Dae-Seong;Park, Byung-Heong;Hur, Jin-Mok;Lee, Han-Soo
    • Korean Journal of Metals and Materials
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    • v.46 no.10
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    • pp.646-651
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    • 2008
  • The electrolytic reduction of spent oxide fuel involves the liberation of oxygen in a molten LiCl electrolyte, which results in a chemically aggressive environment that is too corrosive for typical structural materials. It is essential to choose the optimum material for the process equipment handling molten salt. IN713LC is one of the candidate materials proposed for application in electrolytic reduction process. In this study, yttria-stabilized zirconia (YSZ) top coat was applied to a surface of IN713LC with an aluminized metallic bond coat by an optimized plasma spray process, and were investigated the corrosion behavior at $675^{\circ}C$ for 216 hours in the molten salt $LiCl-Li_2O$ under an oxidizing atmosphere. The as-coated and tested specimens were examined by OM, SEM/EDS and XRD, respectively. The bare superalloy reveals obvious weight loss, and the corrosion layer formed on the surface of the bare superalloy was spalled due to the rapid scale growth and thermal stress. The top coatings showed a much better hot-corrosion resistance in the presence of $LiCl-Li_2O$ molten salt when compared to those of the uncoated superalloy and the aluminized bond coatings. These coatings have been found to be beneficial for increasing to the hot-corrosion resistance of the structural materials for handling high temperature lithium molten salts.

Effect of Powder Preheating Temperature on the Properties of Cu based Amorphous Coatings by Cold Spray Deposition (저온분사로 제조된 Cu계 비정질 코팅층 특성에 미치는 분말 예열 온도의 영향)

  • Cho, Jin-Hyeon;Park, Dong-Yong;Lee, Jin-Kyu;Lee, Kee-Ahn
    • Korean Journal of Metals and Materials
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    • v.47 no.11
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    • pp.728-733
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    • 2009
  • Cu based amorphous ($Cu_{54}Zr_{22}Ti_{18}Ni_{6}$) powders were deposited onto Al 6061 substrates by cold spray process with different powder preheating temperatures (below glass transition temperature: $350^{\circ}C$, near glass transition temperature: $430^{\circ}C$ and near crystallization temperature: $500^{\circ}C$). The microstructure and macroscopic properties (hardness, wear and corrosion) of Cu based amorphous coating layers were also investigated. X-ray diffraction results showed that cold sprayed Cu based amorphous coating layers of $300{\sim}350{\mu}m$ thickness could be well manufactured regardless of powder preheating temperature. Porosity measurements revealed that the coating layers of $430^{\circ}C$ and $500^{\circ}C$ preheating temperature conditions had lower porosity contents (0.88%, 0.93%) than that of the $350^{\circ}C$ preheating condition (4.87%). Hardness was measured as 374.8 Hv ($350^{\circ}C$), 436.3 Hv ($430^{\circ}C$) and 455.4 Hv ($500^{\circ}C$) for the Cu based amorphous coating layers, respectively. The results of the suga test for the wear resistance property also corresponded well to the hardness results. The critical anodic current density ($i_{c}$) according to powder preheating temperature conditions of $430^{\circ}C$, $500^{\circ}C$ was lower than that of the sample preheated at $350^{\circ}C$, respectively. The higher hardness, wear and corrosion resistances of the preheating conditions of near $T_{g}$ and $T_{x}$, compared to the properties of below $T_{g}$, could be well explained by the lower porosity of coating layer.

Effects of Hole Transport Layer Using Au-ionic Doping SWNT on Efficiency of Organic Solar Cells

  • Min, Hyung-Seob;Jeong, Myung-Sun;Choi, Won-Kook;Kim, Sang-Sig;Lee, Jeon-Kook
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.08a
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    • pp.434-434
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    • 2012
  • Despite recent efforts for fabricating flexible transparent conducting films (TCFs) with low resistance and high transmittance, several obstacles to meet the requirement of flexible displays still remain. Indium tin oxide (ITO) thin films, which have been traditionally used as the TCFs, have a serious obstacle in TCFs applications. SWNTs are the most appropriate materials for conductive films for displays due to their excellent high mechanical strength and electrical conductivity. Recently, it has been demonstrated that acid treatment is an efficient method for surfactant removal. However, the treatment has been reported to destroy most SWNT. In this work, the fabrication by the spraying process of transparent SWNT films and reduction of its sheet resistance by Au-ionic doping treatment on PET substrates is researched. Arc-discharge SWNTs were dispersed in deionized water by adding sodium dodecyl sulfate (SDS) as surfactant and sonicated, followed by the centrifugation. The dispersed SWNT was spray-coated on PET substrate and dried on a hotplate. When the spray process was terminated, the TCF was immersed into deionized water to remove the surfactant and then it was dried on hotplate. The TCF film was then was doped with Au-ionic doping treatment, rinsed with deionized water and dried. The surface morphology of TCF was characterized by field emission scanning electron microscopy. The sheet resistance and optical transmission properties of the TCF were measured with a four-point probe method and a UV-visible spectrometry, respectively. This was confirmed and discussed on the XPS and UPS studies. We show that 87 ${\Omega}/{\Box}$ sheet resistances with 81% transmittance at the wavelength of 550 nm. The changes in electrical and optical conductivity of SWNT film before and after Au-ionic doping treatments were discussed. The effects of hole transport interface layer using Au-ionic doping SWNT on the performance of organic solar cells were investigated.

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Wear Problem Improvement Manufacture Technology of Ignitor Tip Component Using 3D Printing Technology (발전소 점화자 팁 부품의 마모 문제 해결을 위한 3D 프린팅 기술을 이용한 부품 제조기술개발)

  • Lee, Hye-Jin;Yeon, Simo;Son, Yong;Lee, Nak-Kyu
    • Journal of Institute of Convergence Technology
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    • v.6 no.2
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    • pp.35-40
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    • 2016
  • Ignitor tip is a component of burner to start the burning process in power plant. This is used to ignite the coal to a constant operating state by fuel mixed with air and kerosene. This component is composed of three components so that air and kerosene are mixed in the proper ratio and injected uniformly. Because the parts with the designed shape are manufactured in the machining process, they have to be made of three parts. These parts are designed to have various functions in each part. The mixing part mixes the supplied air and kerosene through the six holes and sends it to the injecting part at the proper ratio. The inject part injects mixed fuel, which is led to have a constant rotational direction in the connecting part, to the burner. And the connecting plate that the mixed fuel could rotate and spray is assembled so that the flame can be injected uniformly. But this part causes problems that are worn by vibration and rotation because it is mechanically assembled between the mixing part and the inject part. In this study, 3D printing method is used to integrate a connecting plate and an inject part to solve this wear problem. The 3D printing method could make this integrated part because the process is carried out layer by layer using a metal powder material. The part manufactured by 3D printing process should perform the post process such as support removal and surface treatment. However, while performing the 3D printing process, the material properties of the metal powders are changed by the laser sintering process. This change in material properties makes the post process difficult. In consideration of these variables, we have studied the optimization of manufacturing process using 3D printing method.

A Evaluation of Corrosion Resistance on the Thermal Sprayed Coating Tube and Cladded Tube of the Open Rack Vaporizer (용사코팅튜브와 클래드튜브 기화기에 대한 내식성 평가)

  • Baek Jong-Hyun;Lee Jae-Ho;Kim Yong-Seog;Shin Dong-Hyuck;Kim Woo-Sik
    • Journal of the Korean Institute of Gas
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    • v.2 no.4
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    • pp.67-72
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    • 1998
  • Due to excellent corrosion resistance, in particular against sea water, Al-2wt.$\%$Zn alloys have been used as the sacrifice anode material for tube of the ORV. Al-2wt.$\%$Zn alloys thermal-sprayed coating, however, were spalled on the lower part of ORV due to the lack of bonding strength between base material and coating layer and the dropping energy of sea water, To overcome the problems of the thermal spray coating, we developed the cladded tube manufacturing process by coextrusion of the clad and base metal. The corrosion resistance of cladded tube was improved by two times at least, compared with that of the present thermal spray coated vaporizer tubes.

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Properties of Perovskite Materials and Devices Fabricated Using the Solvent Engineered One-Step Spin Coating Method (단일 스텝 스핀 코팅 방법에서 증발 제어 공정 변경에 따른 페로브스카이트 박막 물성 및 태양 전지 소자 특성 변화에 관한 연구)

  • Oh, Jungseock;Kwon, Namhee;Cha, DeokJoon;Yang, JungYup
    • New Physics: Sae Mulli
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    • v.68 no.11
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    • pp.1208-1214
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    • 2018
  • The one-step spin coating method is reported as an excellent thin film process because it can be easily used to fabricate high-quality methyl-ammonium lead tri-iodide ($MAPbI_3$) perovskite layers. One of the important things in the one-step spin coating method towards obtaining high-quality $MAPbI_3$ layers is the anti-solvent (AS) engineering, which consists of an one-step deposition of the $MAPbI_3$ film and dripping of the AS. The properties of the $MAPbI_3$ layer were found to be strongly influenced by the amount, dispensing speed, and spraying time of the AS solution. The $MAPbI_3$ solution was prepared by dissolving lead iodide and methyl-ammonium iodide in N,N-dimethylformamide and adding N,N-dimethyl sulfoxide. Diethyl ether (DE) was used for the AS solution. The results indicate that a $MAPbI_3$ layer appropriately sprayed with DE is beneficial for improving film quality and device efficiency because nucleation of $MAPbI_3$ layer is affected by the characteristics of DE, which affect the film's crystallinity, density, and surface morphology. The $MAPbI_3$ layer, which was optimized by using 0.7 mL of DE, a 3.03 mL/sec dispensing speed, and a 7 second time to spray after spinning showed the best efficiency of 13.74%, which was reproducible.

Density and Corrosion Property Improvement of Zn-Mg Coatings by Controlling the Substrate Temperature during the Deposition (증착 기판 온도 제어에 따른 Zn-Mg 박막의 치밀도 및 내식성 향상에 관한 연구)

  • Song, Myeon-Kyu;La, Joung-Hyun;Kim, Hoe-Kun;Lee, Sang-Yul
    • Journal of the Korean institute of surface engineering
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    • v.50 no.4
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    • pp.266-271
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    • 2017
  • In this study, the corrosion resistance of Zn-3wt.%Mg coating was enhanced by controlling the density of coating. During the deposition the substrate temperature was controlled via an intermittent deposition process, resulting in the improvement of coating density. The maximum substrate temperature during this intermittent deposition process could be controlled from $200^{\circ}C$ to $80^{\circ}C$, depending upon the number of coating layer. The density of Zn-3 wt.%Mg coating increased from 76.1 % to 95.8 % as the substrate temperature was controlled. The salt spray test results revealed that the corrosion resistance of Zn-Mg coated steel could increase 3 times by increasing the density in coatings, while adhesion strength of coating was not changed significantly during 0-T bending test.

Adhesion and Corrosion Resistance of Electrophoretic Paint on "Electroless" Paint Coated AZ31 Mg Alloy

  • Phuong, Nguyen Van;Kim, Donghuyn;Moon, Sungmo
    • Journal of the Korean institute of surface engineering
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    • v.51 no.6
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    • pp.405-414
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    • 2018
  • The present study investigated the adhesion and corrosion resistance of subsequent electrophoretic paint (E-paint) on "electroless" paint coated AZ31 Mg alloy, which was formed by immersion of AZ31 Mg alloy in E-painting solution. It was found that with increasing immersion time of AZ31 in E-painting solution, the amount of paint deposited by electroless process increased but it decreased the electrochemical equivalent of E-painting process and the adhesion of the subsequent E-paint layer. The E-paint on electroless paint coated AZ31 contained pores with the highest pore density and the largest pore size was obtained on the samples with electroless times of 2 and 5 minutes, respectively. Results of the salt-spray test showed an accelerated growth of blisters over the entire surface of the sample immersed for less than 5 minutes whereas blisters were observed only in the vicinity of the scratch in case of samples treated for 15 and 30 minutes. The E-paint on AZ31 with shorter electroless immersion time in E-painting solution was found to have good adhesion and better corrosion resistance.