• Title/Summary/Keyword: amorphous diamond

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Theory of Charged Clusters as New Understanding of Thin Film Growth

  • Hwang, Nong-Moon;Kim, Doh-Yeon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.147-152
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    • 2002
  • A new theory of thin film growth was suggested, where charged clusters of nanometer size are generated in the gas phase and are a major flux for thin films. The existence of these hypothetical clusters was experimentally confirmed in the diamond and silicon CVD processes as well as in metal evaporation. These results imply new insights as to the microstructure control of thin films. Based on this new understanding, the low temperature deposition of crystalline and amorphous silicon can be approached systematically.

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SOLID STATE CESIUM ION BEAM SPUTTER DEPOSITION

  • Baik, Bong-Koo;Choi, Dong-Jun;Han, Dong-Won;Kim, Yong-Hwan;Kim, Seong-In
    • Journal of Surface Science and Engineering
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    • v.29 no.5
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    • pp.474-477
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    • 1996
  • The solid state cesium ion beam sputter deposition system has been developed for negative carbon ion beam deposition. The negative carbon ion beams are effectively produced by cesium ion bombardment. The C-ion beam current and deposition energy can be independently controlled for the deposition of a-D films. This system is very compact, reliable and high flux without any gas discharge or plasma and has been successfully used in the studies of the ion beam deposited amorphous diamond(a-D)

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Corrosion Properties of Carbon-Coated Metallic Bipolar Plate for PEMFC (고분자 전해질 연료전지 금속 분리판 적용을 위한 탄소 박막의 증착과 내식성 평가)

  • Jang, Dong-Su;Lee, Jung-Joong
    • Journal of Surface Science and Engineering
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    • v.48 no.3
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    • pp.87-92
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    • 2015
  • Carbon thin films were deposited on STS 316L sheets by inductively coupled plasma enhanced magnetron sputtering with or without substrate bias voltage. Typical Raman spectrum for amorphous diamond-like carbon (DLC) was obtained, and the interfacial contact resistance (ICR) was measured to show its conductive nature. The electrochemical impedance spectroscopy (EIS) was used to investigate the corrosion mechanism of the carbon coating under the polymer electrolyte membrane fuel cell (PEMFC) condition. According to the pore-corrosion mechanism, the electrolyte penetrates the carbon coating through the pores and reacts with the substrate. As the substrate corrosion proceeds, the pore enlargement occurs and the surface area of the substrate exposed to the electrolyte. Applicability of the carbon coating for the PEMFC bipolar plate was evaluated by potentiodynamic polarization experiments. Finally, an adhesion problem was briefly considered.

A Study on the Anti-Stiction Coating of Glass Lens Mold for Optical Communication (광통신용 글라스렌즈 성형 금형의 이형성 코팅에 관한 연구)

  • Jeong, Woon-Jo;Cho, Jae-Cheol
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.6
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    • pp.962-967
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    • 2017
  • The Diamond-Like-Carbon (DLC) coating is a new carbon-based amorphous material. Carbon ions in the plasma are electrically accelerated and collide with the substrate to form a thin film. This film has similar properties to diamonds such as high surface hardness, low coefficient of friction, corrosion resistance and durability that do not react with acids and bases. Also, since there is no thermal deformation, it can be printed at room temperature. and coated on almost all materials such as paper, polymer, ceramics and various metals even aspheric lens it is possible to mirror surface coating with excellent surface roughness. In this paper, we have analyzed the DLC film formed by Filtered Arc Ion Plating (Filtered AIP) process.

Investigation of Some Hard Coatings Synthesized by Ion Beam Assisted Deposition

  • He, Jian-Li;Li, Wen-Zhi;He, Xial-Ming;Liu, Chang-Hong
    • Journal of the Korean Vacuum Society
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    • v.4 no.S2
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    • pp.163-169
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    • 1995
  • Ion beam assisted deposition(IBAD) technique was used to synthesize hard coatings including diamond-like carbon(DLC), carbon nitride(CN) and metal-ceramic multilayered films. It was found that DLC films formed at low energy ion bombardment possess more $Sp^3$ bonds and much higher hardness. The films exhibited an excellent wear resistance. Nanometer multialyered Fe/TiC films was deposited by ion beam sputtering. The structure and properties were strongly dependent on the thickness of the individual layers and modulation wave length. It was disclosed that both hardness and toughness of the films could be enhanced by adjusting the deposition parameters. The CN films synthesized by IBAD method consisted of tiny crystallites dispersed in amorphous matrix, which were identified by electron diffraction pattern to be $\beta -C_3N_4$.

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Status of Tribology Coating Technology (트라이볼로지 코팅 기술의 현황 및 개발 방향)

  • Kim, Jong-Guk;Gang, Yong-Jin;Kim, Do-Hyeon;Jang, Yeong-Jun
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2017.05a
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    • pp.91-91
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    • 2017
  • 트라이볼로지란? 상대운동을 하면서 서로 영향을 미치는 두면 및 이와 관련된 문제로 마찰, 마모, 윤활에 대한 것을 말한다. 트라이볼로지는 1960대에 조사 연구되기 시작하면서 학문적으로 많은 정리가 이루어졌고, 현재 현대사회에서 문제가 되고 있는 에너지 및 환경 문제를 해결할 수 있는 핵심 요소로 떠오르고 있다. 특히 4차 산업혁명시대를 맞이하여 많은 부분에서는 인공지능, 클라우딩, 빅 데이터 및 로봇 등을 이야기하고 이에 대한 투자 및 개발을 이야기하고 있지만, 이 4차 산업을 뒷받침할, 강인한 제조업이 없으면 불가능한 혁명이라고 말 할 수 있다. 특히 트라이볼로지는 제조업의 무인 자동화 및 무인 로봇 등 이를 필요로 하는 산업 기기와 같은 전반적인 부품 및 소재의 마모를 감소시켜, 기계 장치의 신뢰성을 증가시킬 수 있다. 마찰은 두 물체 상호간의 열 발생을 억제 시키고, 마모는 물체의 표면 경도가 높으면 높을수록 마모량이 적어진다고 알려져있다. 따라서 트라이볼로지와 관련한 표면 처리의 경우, 고온 환경에서의 사용성 증대 및 고경도화 그리고 저마찰을 위한 방향으로 개발 발전되어져 왔다. 트라이볼로지 코팅 중 내마모 코팅의 경우, 티타늄 원소를 기본으로 알루미늄(Al) 및 실리콘(Si)를 합금화하면서, 고경도화 및 내열성을 증대시키는 방향으로 발전되어 왔다. 그에 따라 표면경도의 경우, 4000 Hv, 내열성 $1200^{\circ}C$에 도달였다. 하지만 여전히 철계와의 마찰계수는 0.3 이상으로 이를 낮추는 방법이 요구되고 있다. 최근 트라이볼로지 코팅 중 카본을 함유한 비정질 다이아몬드상 카본 막 (Diamond like Carbon Film : DLC) 이나, Diamond 막의 수요 증가는 마찰을 낮추어 융착마모를 줄이려는 노력으로 볼 수 있다. 특히 수소를 포함하지 않는 고경도 탄소막인 ta-C(tetrahedral amorphous-Carbon)의 수요는 증대되고 있으며, 이에 대한 후막화 및 양산화 기술의 개발의 현재 isssu로 대두되고 있다.

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Hydrocarbon Plasma of a Low-Pressure Arc Discharge for Deposition of Highly-Adhesive Hydrogenated DLC Films

  • Chun, Hui-Gon;Oskomov, Konstantin V.;Sochugov, Nikolay S.;Lee, Jing-Hyuk;You, Yong-Zoo;Cho, Tong-Yul
    • Journal of the Semiconductor & Display Technology
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    • v.2 no.1
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    • pp.1-5
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    • 2003
  • Plasma generator based on non-self-sustained low-pressure arc discharge has been examined as a tool for deposition of highly-adhesive hydrogenated amorphous diamond-like carbon(DLC) films. Since the discharge is stable in wide range of gas pressures and currents, this plasma source makes possible to realize both plasma-immersion ion implantation(PIII) and plasma-immersion ion deposition(PIID) in a unified vacuum cycle. The plasma parameters were measured as functions of discharge current. Discharge and substrate bias voltage parameters have been determined for the PIII and PIID modes. For PIID it has been demonstrated that hard and well-adherent DLC coating are produced at 200-500 eV energies per deposited carbon atom. The growth rates of DLC films in this case are about 200-300 nm/h. It was also shown that short(∼60$\mu\textrm{s}$) high-voltage(> 1kV) substrate bias pulses are the most favorable for achieving high hardness and good adhesion of DLC, as well as for reducing of residual intrinsic stress are.

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Mechanical and electrical properties of ta-C coating Using the Filtered Vacuum Arc System (FVAS 시스템을 이용한 기계적 및 전기적 특성이 우수한 ta-C 코팅막 형성 연구)

  • Gang, Yong-Jin;Jang, Yeong-Jun;Kim, Jong-Guk
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2016.11a
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    • pp.155-155
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    • 2016
  • DLC (Diamond like Carbon)는 Diamond와 유사한 물리화학적 특성을 보유한 막으로 고경도 및 우수한 내마모성, 화학적 안정성의 특성을 가지고 있다. DLC는 크게 카본의 막 형성 공정에서 카본 소스에 따라 수소가 포함된 DLC와 무수소 DLC 로 구분된다. Tetrahedral amorphous carbon (ta-C) 박막은 DLC 박막 중에서 가장 다이아몬드와 유사한 특성을 가지는 박막으로, a:C-H에 비해 고온안정성, 높은 경도 (30~80 GPa) 및 내마모 특성이 우수하여, 현재 다양한 응용분야에 적용되고 있으며, 최근에는 고내구성을 보유하면서 전기적 특성을 가지는 기능성 DLC막의 요구가 증대하고 있다. 본 연구에서는 무수소 DLC 형성을 위해 자장필터가 장착된 Filtered Vacuum Arc Source (FVAS)를 자체적으로 개발하여 연구를 수행하였다. FVAS 장비는 카본 이온 발생부와 Plasma Duct 부위, 전자석부위 구성되어 있으며, 본 연구에서는 Plasma Duct 부위의 Bias 제어를 통한 음극에서 기판으로 이동하는 카본이온의 에너지 및 flux 변화를 통해 ta-C 막의 전기적, 기계적 물성 연구를 진행하였다. Plasma Duct Bias 변화는 각 0 ~ 20 V 조건으로 진행하였으며, 물성 평가는 경도 (Hardness), 마찰계수, 전기적 특성에 대한 분석을 진행하였다. 박막의 증착 거동에서는 Plasma Duct bias 변화에 따라 10 V에서 가장 높은 증착 거동을 가지다 감소하는 경향을 확인 하였으며, 박막의 물성 특성 평가 시에도 이와 유사하게 특성의 차이를 관찰하였다. 이는 음극부위에서 형성된 카본이온이 기판에 도달 시에 Plasma Duct Bias 변화에 따라 이온의 Flux 및 에너지 변화로 인한 박막의 밀도 및 ta-C 막의 물성 변화로 예상되며, 이를 분석하기 위해 라만 분석법을 통해 증명하였다.

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Phase Transition Studies on TiO2 anatase under High Pressure (TiO2 아나타제에 대한 고압 상변이 연구)

  • Hwang, Gil-Chan;Kim, Young-Ho
    • Journal of the Mineralogical Society of Korea
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    • v.25 no.2
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    • pp.77-84
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    • 2012
  • Anatase, one of the $TiO_2$ polymorphs, is known to show different phase transition paths depending on its crystalline and shape. Particle size of 15~25 nm anatase has been subjected to high-pressure Raman spectroscopy and X-ray diffraction studies using a diamond anvil cell. We observe that the starting sample transforms to an amorphous phase above approx. 20 GPa, which is retained upon pressure release to ambient condition. This is in contrast to previously established transition to baddeleyite phase and we suspect difference in the particle distribution state trigger phase instability of nanoparticles and hence amorphization.

Synthesis of CNFs(Carbon Nanofibers)/DAAQ electrode for Supercapacitor (슈퍼커패시티용 DAAQ/CNFs 전극의 제조)

  • Lee, Tae-Soo;Lee, Yun-Hee;Choi, Weon-Kyung;Park, Soo-Gil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07b
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    • pp.1220-1223
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    • 2003
  • A new type electric double layer capacitor (EDLC) was constructed by using carbon nanofibers (CNFs) and DAAQ(1,5-diaminoanthraquinone) electrode. Carbonaceous materials are found in variety forms such as graphite, diamond, carbon fibers etc. While all the carbon nanofibers include impurities such as amorphous carbon, nanoparticles, catalytic metals and incompletely grown carbons. We have eliminated of Ni particles and some carbonaceous particles in nitric acid. Nitric acid treated CNFs could be covered with very thin DAAQ oligomer from the results of CV and TG analyses and SEM images. A crystalline supramolecular oligomer of 1,5-diaminoanthraquinone(DAAQ) was successfully prepared as a thin film by electrochemical oxidation from an acidic non-aqueous medium. DAAQ oligomer film exhibited a specific capacity as 45-50 Ah/kg in 4M $H_2SO_4$. Its electrochemical characteristics were investigated by cyclic voltammetry. And compared with different electrolyte of aqueous type. During ultrasonic irradiation CNFs was to disperse in 0.1M $H_2SO_4$. As a result, CNFs coated by DAAQ composite electrode showed relatively good electrochemical behaviors.

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