• Corrosion Science and Technology
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• 제10권6호
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• pp.212-217
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• 2011

In this study, corrosion characteristics of TiN and ZrN film on the abutment screw by arc-ion plating were investigated using a potentiodynamic anodic polarization test in deaerated 0.9% NaCl solution at $36.5{\pm}1^{\circ}C$. The surface morphologies of the coating layers before and after corrosion test were investigated by a field-emission scanning electron microscope (FE-SEM) and a energy dispersive x-ray spectroscopy (EDS). The surfaces of the TiN and ZrN coated abutment screws showed the smooth surfaces without mechanical defects like scratches which can be formed during the manufacturing process, compared with those of the non-coated abutment screw. The corrosion and passive current densities of TiN and ZrN coated abutment screws were lower than those of the non-coated abutment screw.

• 한국재료학회지
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• 제26권3호
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• pp.160-165
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• 2016

To increase the capacitance of an Al electrolytic capacitor, the anodic oxide film, $Al_2O_3$, was partly replaced by an $Al_2O_3-ZrO_2$ (Al-Zr) composite film prepared by the vacuum infiltration method and anodization. The microstructure and composition of the prepared samples were investigated by scanning electron microscopy and transmission electron microscopy. The coated and anodized samples showed multi-layer structures, which consisted of an inner Al hydrate layer, a middle Al-Zr composite layer, and an outer $Al_2O_3$ layer. The thickness of the coating layer could go up to 220 nm when the etched Al foil was coated 8 times. The electrical properties of the samples, such as specific capacitance, leakage current, and withstanding voltages, were also characterized after anodization at 100 V and 600 V. The capacitances of samples with $ZrO_2$ coating were 36.3% and 27.5% higher than those of samples without $ZrO_2$ coating when anodized at 100 V and 600 V, respectively.

• 한국세라믹학회지
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• 제50권1호
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• pp.37-42
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• 2013

Tristructural-isotropic (TRISO)-coated particles were fabricated by a fluidized-bed chemical vapor deposition (FBCVD) method for use in a very high temperature gas-cooled reactor (VHTR). ZrC as a constituent layer of TRISO coating layers was deposited by a chloride process using $ZrCl_4$ and $CH_4$ source gases in a temperature range of $1400^{\circ}C$ and $1550^{\circ}C$. The change in the microstructure of ZrC depending on the deposition temperature and its effect on the hardness were evaluated. As the deposition temperature increased to $1500^{\circ}C$, the grain size of the ZrC increased and the hardness of the ZrC decreased according to the Hall-Petch relationship. However, at $1550^{\circ}C$, the ZrC layer was highly non-stoichiometric and carbon-rich and did not obey the Hall-Petch relationship in spite of the decrease of the grain size. A considerable amount of pyrolytic carbon at the grain boundaries of the ZrC as well as coarse granular pyrolytic carbon were locally distributed in the ZrC layer deposited at $1550^{\circ}C$. Therefore, the hardness decreased largely due to the formation of a large amount of pyrolytic carbon in the ZrC layer.

• 한국결정성장학회지
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• 제31권6호
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• pp.282-286
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• 2021

Laser-carburized TiZrN 코팅의 침탄 공정에서 탄소 페이스트 두께에 따른 탄소의 침투 깊이 및 압축잔류응력 변화를 탄소 포텐셜 측면으로 비교·고찰하였다. 스크린 프린팅과 스핀 코팅 방법을 이용하여 각각 1.1 mm와 0.4 mm의 두께로 탄소 페이스트를 도포하고, 동일한 레이저 조사 조건에서 레이저 침탄을 실시하였다. 탄소 페이스트가 두꺼워질수록 침탄된 TiZrN 시료의 회절 패턴이 더 저각으로 이동하였으며, 고용체 강화 및 격자 왜곡의 심화를 나타내었다. TEM을 이용한 미세구조 분석에서도 두꺼운 페이스트로부터 침탄된 TiZrN 내 결정질 결함이 증가하고 높은 탄소 농도를 보였으며, 이는 페이스트 두께가 두꺼워질수록 탄소 포텐셜도 높아짐을 의미하였다. XPS depth profile 분석에서도 두꺼운 페이스트를 통해 침탄된 TiZrN 시료에서 높은 탄소 농도 및 탄화물 형성을 보이면서, 탄소 페이스트 두께 조절에 의해 침탄에서 표면 탄소농도와 탄소 포텐셜 증가가 일어남을 나타내었다. 아울러, 탄소 농도의 증가는 표면의 압축잔류응력 증가(3.67 GPa에서 4.58 GPa로)에 기여하였음을 확인하였다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1995년도 특별강연 및 추계학술발표 개요집
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• pp.123-125
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• 1995

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2012년도 추계총회 및 학술대회 논문집
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• pp.170-170
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• 2012

• 한국결정성장학회지
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• 제30권1호
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• pp.7-11
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• 2020

TiZrN 코팅의 도핑 공정에서 탄소 페이스트 증착 방식에 따른 탄소의 용해성 변화를 격자왜곡(lattice distortion)과 원자농도(atomic concentration)를 통해 비교 및 고찰하였다. 딥코팅, 스핀코팅과 스크린프린팅 방식을 이용하여 탄소 페이스트를 도포한 후, 레이저를 조사하여 탄소 구배층(carbon gradient layer)을 형성시켰다. 모든 구배층은 탄소가 도핑되는 구조였으며, 두께 및 탄소 도핑량은 페이스트 도포 방식에 의존하였다. 결정 구조 분석 결과, 딥코팅에 의해 코팅층을 도핑할 때 보다 스핀코팅과 스크린프린팅에 의해 코팅층을 도핑하였을 때, 더 큰 격자 팽창이 일어남을 확인할 수 있었다. 또한 XPS depth profile을 통해 딥코팅에 의한 탄소 구배층 두께는 약 30 nm, 스핀코팅과 스크린프린팅의 경우 대략 100 nm로 더 깊은 구배층이 형성됨을 확인하였다. 침탄 전 코팅의 경도는 약 30 GPa였으며, 침탄 후에는 딥코팅 시편의 평균 경도가 약 31 GPa였고 스핀코팅과 스크린프린팅의 평균 경도는 대략 37 GPa로 증가한 것으로 보아 탄소 도핑을 통한 격자팽창 및 구배층의 영향을 확인하였다.

• 한국세라믹학회지
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• 제41권5호
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• pp.349-352
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• 2004

Organic-inorganic hybrid sol based on ZrO$_2$-SiO$_2$ system was prepared by sol-gel process. Firstly, ZrO$_2$ non-aqueous precursor sol was synthesized and then organosilane compounds which include epoxy silane (GPTS; 3-g1ycidoxypropyl tri-methoxysilane) and acryl silane (ACS; (3-(tri-methoxysilyl)propylmethacrylate)) were added to ZrO$_2$precursor sol for hybridization. Finally, com-mercial silica sol was added to improve the mechanical properties. Synthesized organic-inorganic Zr-hybrid sol was coated on polycarbonate substrate for enhancing it’s mechanical properties, especially hardness. Vicker’s hardness of polycarbonate sub strate was increased from 13.6 to 17.8 MPa and its pencil hardness was increased from 2 to 7 H, respectively, after coating and drying at 10$0^{\circ}C$ for 30 min.

• 한국세라믹학회지
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• 제35권8호
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• pp.791-794
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• 1998

• KSTLE International Journal
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• 제6권2호
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• pp.45-50
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• 2005

Plasma ceramic spray that is applied on a machine part under severe work conditions has been investigated for tribological behavior. The application of ceramic coatings by plasma spray has become essential in tribosystems to produce wear resistance and long life in severe conditions. The purpose of this study was to investigate the wear characteristics of $8\%Y_{2}O_3-ZrO_2$ coating, in view of the effect of post-spay heat treatment. The plasma-sprayed $8\%Y_{2}O_3-ZrO_2$ coating was studied to know the relationship between phase transformations and wear behavior related to post-spray heat treatment. Wear test was carried out with ball on disk type on normal loads of 50N,70N and 90N under room temperature. The phase transformation of phase and the value of residual stress were measured by X-ray diffraction method(XRD). Tribological characteristics and wear mechanisms of coatings were observed by SEM. The tribological wear performance was discussed in the focusing of residual stress. Consequently, post-spray heat treatment plays an important role in decreasing residual stress. Residual stress in the coating system has a significant influence on the wear mechanism of coating.