• Journal of Ocean Engineering and Technology
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• v.13 no.1 s.31
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• pp.62-69
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• 1999

67Ni-22Cr-10Al-1Y and $ZrO_2-8Y_2O_3$ were coated on the substrate surface of ST304 and Al2024 by the plasma spraying method. The adgesion of the films varies depending on the substrates and the laminating method. In the case of STS304, the cracks were observed at thermal shock temperature difference ${Delta}T$ of $900^{circ}C$ in the non functionally gradient material(NFGM) and at $1100^{circ}C$ in the functionally gradient material(FGM). The film adhesion of the FGM is better than that of the NFGM in ST304. The cumulative AE count of the FGM of STS304 increased continuously at the bending test. But the NFGM of STS304 showed discontinuity of the AE count. The total AE count for the FGM of STS304 decreased as the number of thermal shock increased, and this tendency was evident as the thermal shock temperature difference increased.

• Journal of the Korean institute of surface engineering
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• v.55 no.6
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• pp.376-382
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• 2022

Yb₂Si₂O₇ has a coefficient of thermal expansion similar to that of the base material of SiC and has excellent corrosion resistance in a high-temperature oxidizing atmosphere including water vapor, so it is being studied as one of the materials for environmental barrier coatings (EBCs). In this study, Yb₂Si₂O₇ powder granule is deposited using atmospheric plasma spraying (APS) with different Ar/He ratios. Phase formation and microstructural characteristics are investigated with the coated specimens. In the coating layer, the crystallinity decreased, and the amorphous content increased from an increase in the ratio of Ar. In addition, the various types of particles involved by local volatilization of Si according to the Ar/He ratios were identified.

• Journal of the Korean institute of surface engineering
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• v.41 no.5
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• pp.220-225
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• 2008

In this study, two kinds of Fe-based bulk metallic glasses (BMG) powder were built-up through atmospheric plasma spray (APS) technique. The microstructure of two coatings was analyzed through X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Crystallization and oxidation in coatings were affected by chemical composition and initial powder size. Then, both of them influenced the tribological property.

• Tribology and Lubricants
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• v.22 no.6
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• pp.335-341
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• 2006

This paper reports the wear characteristics of two types of coating materials, which are $Cr_2O_3$ and $ZrO_2$, by coated plasma thermal spray method. The wear test was carried out under air, grease, and bearing fluid conditions. The wear testing machine of a pin-on disk type were used to measure friction forces, friction coefficients and the weight losses of the coating specimens on the various sliding velocity and loading condition. The wear surface of specimens were observed by scanning electron microscope (SEM) photographs.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.35-40
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• 2003

본 연구에서는 취성재료이면서, 세라믹과 유사한 성질을 가지며 내부균열관찰이 용이한 상업용 유리의 표면에 세라믹 플라즈마 용사 코팅한 후 입자 충격시험을 실시하였다. 코팅분말로는 매마모성 및 내충격성이 우수하여 산업계에서 널리 사용되고 있는 $Al_{2}O_{3}$ 분말을 사용하였으며, 충격입자로는 고경도의 STB2 볼베어링강을 사용하였다. 공기압축기를 장착한 입자 충격시험기를 이용하여 강구입자 충격시험을 실시한후, 실체현미경을 이용하여 손상정도를 분석하였다. 그리고 코팅입자의 크기 및 기공율에 따른 손상 정도를 분석 방법에 따라 손상정도를 비교${\cdot}$검토하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.2
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• pp.162-168
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• 2009

In this study, disk type of thermal barrier coating system for gas turbine blade was isothermally aged in the furnace changing exposure time and temperature. The aging conditions that delamination occurs were determined by the extensive microscopic analyses and bond tests for each aging condition. The delamination map was drawn from the time-temperature matrix form which summarize the delamination conditions. Finally, a method to draw the delamination life diagram of a thermal barrier coating system by using the delamination map was suggested.

• Journal of Power System Engineering
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• v.2 no.2
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• pp.35-40
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• 1998

In this study, the author investigated the effects of strengthening treatments on the mechanical properties of plasma sprayed Ni-base self fluxing alloy. Strengthening treatments for sprayed specimens were carried out in 4 different temperature conditions in vacuum furnace. The mechanical properties, such as microhardness, thermal shock resistance and erosion resistance were tested for the sprayed specimens after strengthening treatments. And it was proved that the mechanical properties of coating layer were much improved by strengthening treatments.

• Tribology and Lubricants
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• v.22 no.5
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• pp.282-289
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• 2006

This paper is to investigate the wear behaviors of two type ceramics, $Al_{2}O_{3}\;and\;TiO_{2}$, by coated plasma thermal spray method under the lubricative environment. The lubricative environments are grease fluids, a general hydraulic fluids, and bearing fluids. The wear testing machine used a pin on disk type. Wear characteristics, which were friction force, friction coefficient and the specific wear rate, according to the lubricative environments were obtained at the four kinds of load and sliding velocity is 0.2 m/sec. After the wear experiments, the wear surfaces of the each test specimen were observed by a scanning electronic microscope.

• Journal of Welding and Joining
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• v.22 no.5
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• pp.46-52
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• 2004

AlSi-Al$_2$O$_3$ composite layer was prepared by plasma spray on steel substrate. The composite powder for plasma spray was prepared by simple mechanical blending. The wear resistance of the composite layers and matrix aluminum alloy were performed in terms of size distribution of ceramic particles. Friction coefficients of AlSi were decreased with incorporation of $Al_2$O$_3$. The tribological properties of coated layers were affected by the size of incorporated $Al_2$O$_3$ particle. The reinforcement of $Al_2$O$_3$ particle into aluminum alloy matrix decreased the friction coefficient as well as wear loss.

• Korean Journal of Materials Research
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• v.9 no.1
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• pp.18-24
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• 1999

This study was performed to observe the surface roughness and microstructural change of the grinding surface of plasma sprayed $Cr_2$$O_3$coating layer. The experimental condition were particle size of diamond grinding stone, depth of cut, rotating speed and coolant feed. As a results, the grinding conditions influencing on the surface roughness and microstructure were depth of cut and the particle size of diamond grinding stone. In addition to the conversion of brittle-ductile fracture of grinding surface on depth of cut is $5~10\mu\textrm{m}$ and rotating speed was 100 r.p.m after grinding