Warm spray를 이용한 알루미늄-알루미나 복합 코팅층의 제조 및 특성

권의표,이종권,Kwon, Eui-Pyo,Lee, Jong-Kweon 한국재료학회 2017 한국재료학회지 Vol.27 No.7

Properties of coatings produced by warm spray were investigated in order to utilize this technique as a repair method for Al tire molds. $Al-(0-10%)Al_2O_3$ composite powder was sprayed on Al substrate by warm spraying, and the microstructure and mechanical properties of the composite coating layer were investigated. For comparative study, the properties of the coating produced by plasma spray, which is a relatively high-temperature spraying process, were also investigated. The composite coating layers produced by the two spray techniques exhibited significantly different morphology, perhaps due to their different process temperatures and velocities of particles. Whereas the $Al_2O_3$ particles in the warm sprayed coating layer maintained their initial shape before the spray, flattened and irregular shape $Al_2O_3$ particles were distributed in the plasma sprayed coating layer. The coating layer produced by warm spray showed significantly higher adhesive strength compared to that produced by plasma spray. Hardness was also higher in the warm sprayed coating layer compared to the plasma sprayed one. Moreover, with increasing the fraction of $Al_2O_3$, hardness gradually increased in both spray coating processes. In conclusion, an $Al-Al_2O_3$ composite coating layer with good mechanical properties was successfully produced by warm spray.

Optimal Condition of Hydroxyapatite Powder Plasma Spray on Ti6Al4V Alloy for Implant Applications

Ahn, Hyo-Sok,Lee, Yong-Keun Materials Research Society of Korea 2012 한국재료학회지 Vol.22 No.4

Optimal conditions for HA plasma spray-coating on Ti6Al4V alloy were investigated in order to obtain enhanced bone-bonding ability with Ti6Al4V alloy. The properties of plasma spray coated film were analyzed by SEM, XRD, surface roughness measurement, and adhesion strength test because the film's transformed phase and crystallinity were known to be influential to bone-bonding ability withTi6Al4V alloy. The films were formed by a plasma spray coating technique with various combinations of plasma power, spray distance, and auxiliary He gas pressure. The film properties were analyzed in order to determine the optimal spray coating parameters with which we will able to achieve enhanced bone-bonding ability with Ti6Al4V alloy. The most influential coating parameter was found to be the plasma spray distance to the specimen from the spray gun nozzle. Additionally, it was observed that a relatively higher film crystallinity can be obtained with lower auxiliary gas pressure. Moderate adhesion strength can be achievable at minimal plasma power. That is, adhesion strength is minimally dependent on the plasma power. The combination of shorter spray distance, lower auxiliary gas pressure, and moderate spray power can be recommended as the optimal spray conditions. In this study, optimal plasma spray coated films were formed with spray distance of 70 mm, plasma current of 800 A, and auxiliary gas pressure of 60 psi.

Thermal and mechanical evaluation of the thermal barrier layers coated by spray dried granules

Ju Hyoung Cho,Tae Woo Kim,Yeon Gil Jung,이기성 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.3

In this study yttrium stabilized zirconia (YSZ) spray dried granules are produced and applied for thermal barrier coatings in gas turbine applications. The morphologies of the spray dried granules are varied by the control of the solvent type, binder/ dispersant content and process parameters during spray drying. The feed rate depends on the morphologies of the granules. The spray dried granules are deposited over a NiCrCoAlY bond coat by an air plasma spray coating apparatus for the thermal barrier coatings. We evaluated the thermal tolerance of the thermal barrier layers by thermal annealing tests and hardness tests after the thermal annealing tests. As a result, the thermal barrier coating using pre-heat treated spherical powder gave advantages in thermal and mechanical resistances after the thermal annealing test. In this study yttrium stabilized zirconia (YSZ) spray dried granules are produced and applied for thermal barrier coatings in gas turbine applications. The morphologies of the spray dried granules are varied by the control of the solvent type, binder/ dispersant content and process parameters during spray drying. The feed rate depends on the morphologies of the granules. The spray dried granules are deposited over a NiCrCoAlY bond coat by an air plasma spray coating apparatus for the thermal barrier coatings. We evaluated the thermal tolerance of the thermal barrier layers by thermal annealing tests and hardness tests after the thermal annealing tests. As a result, the thermal barrier coating using pre-heat treated spherical powder gave advantages in thermal and mechanical resistances after the thermal annealing test.

사료용 비타민제의 피복을 위한 aerothermal fluidization spraying(ATFS) system의 개발

이무준,이준엽,김창혁,오상집 강원대학교 동물생명과학연구소(구 강원대학교 동물자원공동연구소) 2004 동물자원연구 Vol.15 No.-

Hybridization system, Spraying chamber coating system and aerothermal fluidization spraying (ATFS) system, were tested to find an economic and practical method for vitamin coating. Ae coating by hybridization was done by commercial hybridizer. But both spraying chamber and aerothermal fluidization spraying system were developed by authors for this test. Two vitamins, Vit. E and Vit. C, were employed for coating with four different coating materials, such as eudragit, corn zein, ethylcellulose and gelatin. Coating by hybridization was unsuccessful due to high intake velocity, temperature increase, and bridge formation between vitamin particles. Spraying chamber system was marginally successful to coat vitamins. But the quality of coated vitamin was poor possibly because of the failure of uniform mixing between vitamin and coating materials inside the chamber. Vitamin coating was successfully achieved by ATFS system. The system enables to give not only uniform mixing between coating material and vitamin, but also drying of coated vitamin and uniform diffusion of vitamin particles by thermal aeration. This result was also confirmed through surface micrograph by scanning electron microscope. Therfore, the ATFS system can be considered as a practical system for coating sensitive materials such as vitamins as well as other feed additives.

AE에 의한 플라즈마 용사코팅 염수분무 부식재의 인장해석

김귀식,박경석,홍용의,현창해 제주대학교 공과대학 첨단기술연구소 2001 尖端技術硏究所論文集 Vol.12 No.2

Thermal spray coating is formed by a process in which melted particles flying with high speed towards substrate, then crash and spread on the substrate surface cooled and solidified in a very short time. Stacking of the particles makes coating. This paper was to investigate the adhesiveness of the plasma sprayed coating materials conducted 5% NaCl salt spray by acoustic emission method in tensile loadings. The powders used for the coating were nickel aluminum composite powder Ni-4.5wt.%Al and titanium dioxide powder TiO_2. The salt solution penetrated into the surface of the substrate through pore of the coating layer built in the process of plasma spray. Corrosion productions formed on the surface of substrate. The adhesiveness between the substrate and the coating layer is weaken by corrosion and the exfoliation initiated chiefly at the corrosion surface of the substrate. The AE events and energy of the corroded coating specimens decreased as the salt spray times increase.

플라즈마 스프레이를 이용한 세라믹 코팅층의 부식특성에 관한 연구

김동화,송요승,윤종구,채경선,안준홍 한국 항공대학교 항공산업기술연구소 1999 航空宇宙産業技術硏究所 硏究誌 Vol.9 No.-

여러 산업체에선 한계된 금속의 성질을 필요한 용도에 맞게 합금원소를 첨가하므로써 개선해 왔으나, 이는 제한된 범위를 가지고 있으며, 그 효과가 작다. 최근에는 금속표면에 피막을 입혀 효율적으로 제품을 개선하여 생산하고 있다. 피막을 입히는 기술로는 용사법을 비롯하여 CVD, PVD, 양극산화법, 전기 및 화학도금등 그 종류는 다양하다. 금속위에 표면처리를 하여 세라믹피막을 얻으므로써 단열피복, 내마모성, 내식성, 내열성, 열전도 차폐등 물리적, 기계적 성질을 개선하고 있다. 이번 연구에서는 표면에 세라믹 보호 피막을 생성하는 process로 plasma spray법을 이용하여 Titanium 모재위에 Cr₂O₃-TiO₂, Al₂O₃-TiO₂,그리고 NiCoCrAlYO₂의 4종류의 세라믹 powder로 용사층을 형성, 물리적 특성을 분석하였고, 또한 bond coating 재료로는 NiCoCrAlYO₂분말을 사용하여 bond coating을 형성시키기 전과 후의 물성을 비교하였다. 특히 세라믹 피막의 기공도시험, 표면거칠기시험등을 통하여 피막의 내식성향상에 어떠한 영향을 주는지 XRD, SEM, 전기화학적 분극시험을 통해 중점적으로 연구하였다. 연구 결과 Al₂O₃-TiO₂피막층과 NiCoCrAlYO₂(bond coating layer)+Al₂O₃-TiO₂피막층이 우수한 내식성을 나타내며, 대체적으로 bond coating layer가 존재하지 않는 피막의 기공도와 표면거칠기의 평균값이 낮게 나오며, 내식성 역시 우수한 것으로 확인하였다. The ceramic material coating is used to protecting the underground pipe, ship, and water tank from corrosion environment. Recently, an advanced nation has made a lot of study to develop the semi-permanent insoluble cell using ceramic coating on valve metal(substrate). Therefore in this study the plasma spray method was used to make the protection coating. The ceramic materials for coatings were Cr₂O₃-TiO₂, Al₂O₃-TiO₂and the bond coating materials for bond strength was NiCoCrAlYO₂. As a results, the Al₂O₃-TiO₂ coating without bond coating(NiCoCrAlYO₂) represent the excellent anticorrosion property against corrosion environment.

Twin wire arc spray 용사코팅 공정을 통해 제작된 미끄럼 방지 코팅의 열적 특성 및 고온노출 거동 연구

권한솔,박영진,남욱희,변응선 대한금속·재료학회 2023 대한금속·재료학회지 Vol.61 No.9

Conventional non-skid coatings for marine construction contain polymeric materials. Thesematerials are generally susceptible to high temperature environments because of their low thermalconductivity and thermal resistance. A metal-based non-skid coating has great potential for hightemperature applications, yet, there has only been limited research. In this study, twin wire arc spray(TWAS) was used to fabricate Al and Al-3%Ti coatings on a high strength low alloyed (HSLA) steelsubstrate. The purpose of this study is to confirm the feasibility of TWAS Al-based coating for non-skidareas on marine construction. The static coefficient friction of TWAS Al-based coatings exhibited excellentand uniform values compared with a conventional epoxy-based non-skid coating. The specific heat andthermal conductivity of TWAS Al-based coating was measured and compared with that of the substrate. The thermal property values of the TWAS Al-based coating were reported for the first time in this study. The TWAS Al-based coating had A continuous interface with the substrate and the generalmicrostructural features of a thermal-sprayed metal coating. After exposure to 500oC for 24 hours, thean Fe-Al intermetallic compound and oxide were formed inside of the coating and coating-substrateinterface. The adhesion strength indicated that the TWAS Al-based coating sustained its strength afterthe isothermal exposure test. The Vickers hardness of the TWAS Al-3%Ti coating was higher than thatof the Al coating. The solid solution hardening of Ti atoms in the as-deposited coating and theprecipitation hardening of the TiAl3 compound in the heat-treated coating contributed to theimprovement of in Vickers hardness. Thus, the TWAS Al-3%Ti coating is proven to be a promising nonskidcoating for high temperature applications.

최적 고속화염용사법으로 제조된 Diamalloy4006 코팅의 내마모 특성

주윤곤,윤재홍,정연길,이재현,Joo, Yunkon,Yoon, Jaehong,Jung, Yeongil,Lee, Jehyun 한국재료학회 2015 한국재료학회지 Vol.25 No.9

The effects of coating parameters were investigated in wear resistance coatings of Diamalloy-406 on Inconel 718 to obtain an optimum coating condition by high velocity oxy-fuel spraying. The coating parameters, the flow rates of source gases (hydrogen and oxygen), the powder feed rate, and the spray distance, were designed by the Taguchi method. The optimal conditions were determined: oxygen flow rate 34 FRM, hydrogen flow rate 57 FRM, powder feed rate 35 g/min, and spray distance 7 inch. Friction coefficients of the coating and the substrate decreased with an increasing sliding surface temperature from $25^{\circ}C$ to $450^{\circ}C$. The friction coefficient of Diamalloy-4006 coating decreased as the sliding surface temperature increased from $0.43{\pm}0.01$ at $25^{\circ}C$ to $0.29{\pm}0.01$ at $450^{\circ}C$. The wear trace and wear depth of the coating were smaller than the substrate at all temperatures tested. The relationship between spray parameters and wear resistance was discussed extensively, based on the measured roughness, hardness, and porosity in each coating.

에어리스 스프레이 도장용 노즐 팁 설계에 관한 연구

김동건(Dong-Keon Kim),김순경(Soon-Kyung Kim) 한국기계가공학회 2012 한국기계가공학회지 Vol.11 No.6

This study was carried out to design the spray nozzle tip for airless spray coating. Airless spray coating is the process of coating an object with a liquid spray of paint or other fluid. The nozzle tip controls the fluid flow rate and creates back pressure in the system. The nozzle tip also defines the spray pattern by the size and shape of the orifice. The spray pattern of nozzle tip was investigated numerically using ANSYS CFX ver. 14.0. It was observed that performance result of designed nozzle tip was correspond well, compared with that of GARCO nozzle tip.

선박용 피도물 도료 사용량 절감을 위한 인식 및 스프레이 자동제어시스템 개발

정영득 대한안전경영과학회 2019 대한안전경영과학회지 Vol.21 No.3

The first aim of the study is to improve the productivity by uniformizing the thickness of coating and reducing quality-inspection time. The second aim is to cut down on the raw materials for coating by prevent the waste of spraying in the air during a painting process through a real-time coating-sizerecognition monitering to fit the target components. To achieve the two aims, a simplified version of automatic coating control system for recognition of coating for vessels and Spray. With the sytem, following effects are expected: First, quality improvement will be achieved by uniformizing the film-thickness. Second, it will reduce the waste of coating paint by constructing the speed of the coating, the spray gun robot transfer time, and the number of DBs according to the size of the vessel. Third, as a 3D industry, it will be able to solve the difficulty of supply of labors and save up the labor costs. Therefore, in the future, further research will be needed to be applied to various products with DB design that designates the variable value, which is added for each type of pieces by comparing the difference between various types of workpieces and linear ones.