• Transactions of the Korean hydrogen and new energy society
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• v.21 no.3
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• pp.201-206
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• 2010

In present work, $La_{0.8}Ca_{0.2}CrO_3$ (LCC) ceramic interconnect layer for SOFC was prepared by using thermal plasma spray coating process. The LCC powders were synthesized by Pechini method and calcined at the temperature of $1000^{\circ}C$. The prepared LCC powder was characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), particle counter, BET analysis, respectively. In addition, basic and essential properties of LCC layer coated by thermal plasma spray coating process such as the morphology of surface and cross section for coated layer, gas leak rate, and electrical conductivity were analyzed and discussed. Based on these experimental results, it can be concluded that the LCC layer coated by thermal plasma spray coating process can be suitable as a ceramic interconnect of SOFC operated at $800^{\circ}C$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.1
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• pp.32-38
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• 2014

In the present study, immersion corrosion characteristics of Zn and Al thermal spray coating with sealer for the seawater heat exchanger are experimentally investigated. Total 8 coating types of Zn and Al thermal spray coating with silicone and epoxy sealer were tested with immersion corrosion testing in $80^{\circ}C$ 3.5%w NaCl solution and compared the corrosion characteristics between each coatings. To investigate the corrosion characteristics of the specimens, AC impedance, SEM, and thermal diffusivity were acquired and analyzed. As a result, on the surface of the specimens with silicone and epoxy sealer, blister did not occurred, so the sealers might be effective at increasing the corrosion resistance of the specimens immersed in the NaCl solution.

• Journal of Power System Engineering
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• v.13 no.5
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• pp.89-94
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• 2009

In this work, the optimal process has been designed by $L_9(3^4)$ orthogonal array and analysis of variance(ANOVA) for thermal-sprayed Ni-based hard coating. Ni-based hard coatings were fabricated by flame spray process on steel substrate. Then, the hardness test and observation of microstructure of the coatings were performed. The results of hardness test were analyzed by ANOVA. The ANOVA results demonstrated that the acetylene gas flow had the greatest effect on hardness of the coatings. The oxygen gas flow was found to have a neglecting effect. From these results, the optimal combination of the flame spray parameters could be predicted. The calculated hardness of the coatings by ANOVA was found to lie close to that of confirmation experimental result. Thus, it was considered that design of experiments design using orthogonal array and ANOVA was useful to determine optimal process of thermal-sprayed Ni-based hard coating.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.826-829
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• 2004

An increasing interest in fire safety engineering can currently be identified in Korea and overseas. The fire-resistant characteristics of spray coating material for fire protection with or without nano $Al(OH)_3$ colloid has been experimentally investigated and the results are presented in this paper. The fire-resistance characteristics of spray coating material with nano $Al(OH)_3$ were superior to those without $Al(OH)_3$. Especially, spray coating material with nano material showed that thermal characteristic in the early days was remarkably excellent.

• Journal of the Korean Solar Energy Society
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• v.26 no.3
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• pp.9-16
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• 2006

A solar collector surface coated with a low emission material is still imported from other developed countries expensively. Thus it is very significant to develop a new coating method with a cheap alternative coating material instead of the imported high-cost collector surface. A thermal spray method was adopted to coat a cheap Titania on a copper plate. Generally, a new coating on the copper plate was conducted successfully by selecting a proper ratio of carbon and acetylene. By measuring an absorption rate of solar and heat emission rate, all the plate types gained a high absorption rate of 98% approximately, more or less, but all of the types still have a high emission. Finally it was clear that more research is needed to advance the coated-plate to subdue the high emission from the hot plate surface and the higher the Titania's proportion is, the lower the emission is on the surface.

• Proceedings of the KWS Conference
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• 2010.05a
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• pp.32-38
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• 2010

Hybrid material(ceramic+metal) processes were developed for micro filter using ceramics coating at metal filter surface by thermal spray method, micro hole drilling at ceramic coated filter surface by femtosecond laser, and fiber laser direct welding of ceramic and metal (SUS304, SM45C) by capillary effect. Thermal spray process was used for ceramic powders and metal filters. The used ceramic powders were $Al_2O_3+40TiO_2$(Metco 131VF) powder of maximum particle size $5{\mu}m$ and ${Al_2O_3}99+$(Metco 54NS) power of maximum particle size 45m. Ceramic coated filters using thermal spray method had a great influence on powder material, particle size and coating thickness but had a fine performance as a micro filter. CW fiber laser was used to drill the top ceramic layer and melt the bottom metal layer for joining applications.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.710-714
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• 2011

In present work, $La_{0.8}Ca_{0.2}CrO_{3}$(LCC), $La_{0.8}Sr_{0.2}CrO_{3}$(LSC) and $La_{0.8}Ca_{0.2}CrO_{0.9}Co_{0.1}O_{3}$(LCCC) ceramic interconnect layer for SOFC were prepared by using thermal plasma spray coating process. The LCC, LSC and LCCC powders were characterized by x-ray diffraction(XRD), scanning electron microscopy(SEM), particle counter and BET analysis. In addition, basic and essential properties such as the surface morphology, cross section, gas leak rate, and electrical conductivity of LCC, LSC, and LCCC layers coated by thermal plasma spray coating process were analyzed and discussed. Based on these experimental results, it can be concluded that the LCCC layer coated by thermal plasma spray coating process can be suitable as a ceramic interconnect of SOFC.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.195-199
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• 2007

In this study, bond strength tests were performed for the thermal barrier coating applied to the 1st stage turbine blade. After the tests, the specimens were cut and the locations of failure were observed by using optical microscope. The influence of heat treatment on bond strength of a bond coating and the difference among the three types of bond coatings are treated.

• Corrosion Science and Technology
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• v.22 no.2
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• pp.108-114
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• 2023

In this study, anti-corrosion effect was investigated through various electrochemical experiments after applying Al thermal spraying technology to AA5083-H321. Open circuit potential and anodic polarization curves were analyzed through electrochemical experiments in natural seawater. The shape of the surface was observed using a scanning electron microscope (SEM) and a 3D microscope before and after the experiment. Component and crystal structure were analyzed through EDS and XRD. As a result, the surface roughness of AA5083-H321 and the Al thermal sprayed coating layer increased due to surface damage caused by anodic dissolution reaction during the anodic polarization experiment. The corrosion rate of AA5083-H321 was relatively low because the Al thermal spray coating layer contained structural defects such as pores and crevices. Nevertheless, the open circuit potential of the Al thermal spray coating layer in natural seawater was measured about 0.2 V lower than that of AA5083-H321. Thus, a sacrificial anode protection effect can be expected.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.55.2-55.2
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• 2010

기존의 thermal spray coating은 분사시 가스와 입자가 높은 열을 동반하여 상대적으로 차가운 기판과의 충돌되는 과정에서 기판과 입자 사이에 열응력이 발생하게 되고, 이것은 코팅 특성을 저하시킨다. 또한 고온의 가연성 가스등의 사용으로 작업 시 안전문제 등의 단점이 있었다. 이러한 단점을 보완하기 위하여 분사 시 운동에너지를 주로 이용하는 cold spray coating 공정이 개발되었다. 이 공정은 코팅 입자를 임계속도 이상으로 가속시켜 입자와 기판이 충돌시 소성 변형을 통해 적층되는 코팅기술이다. Cold spray coating공정은 상온 코팅이 가능하기 때문에 주입입자의 물성이 비교적 그대로 유지되고, 고온의 열로 인한 기판의 변질을 막을 수 있다. Cold Spray coating에서 주로 원형 노즐을 사용하나 본 연구에서는 분사 효율 향상을 위한 광폭노즐을 사용하여 코팅 시간 단축을 기대하고 있다. 임계속도 이상의 입자 확보를 위하여 노즐의 expansion ratio와 노즐 shape의 변화를 주어 그에 따른 노즐내의 유동장을 수치해석을 통해 계산하였다. 분사되는 출구면과 기판 사이의 입자 속도 분포를 해석하였고, 이를 통해 임계속도 이상의 속도를 갖는 유효 입자들의 분포 및 유효 분사 면적을 예측하였다. 또한, 기존의 원형 노즐과 광폭 노즐과의 유동장 비교 및 각 노즐 분사면을 분석하여 cold spray coating공정에서의 효율적인 노즐 형상을 디자인하였다.