• Title/Summary/Keyword: DLC layer

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Dependence of $Cl_2$ Gas Reaction Time on Tribological Properties of TiC Derived Carbon Layer (염소가스 반응시간에 따른 TiC표면 탄소막의 Tribology 특성)

  • Lim, Dae-Soon;Bae, Heung-Taek;Jeong, Ji-Hoon;Na, Byung-Chul
    • Tribology and Lubricants
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    • v.25 no.1
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    • pp.20-24
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    • 2009
  • TiC-derived carbon coatings have been synthesized at $600^{\circ}C$ temperature treatment with $H_2/Cl_2$ mixture gases. From Raman spectroscopy measurements, the modified layer was covered with carbon and the thick-ness of the layer was increased with increasing reaction time. And $I_D/I_G$ ratio was decreased with increasing reaction time. The superior tribological property was obtained from TiC reacted with $Cl_2$ gas for 2 hrs. And the tribological property measurements indicate that TiC-derived carbon layer has $0.9{\times}10_{-6}mm^3/Nm$ in wear coefficient and 0.13 in friction coefficient.

Nucleation, Growth and Properties of $sp^3$ Carbon Films Prepared by Direct $C^-$ Ion Beam Deposition

  • Kim, Seong I.
    • The Korean Journal of Ceramics
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    • v.3 no.3
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    • pp.173-176
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    • 1997
  • Direct metal ion beam deposition is considered to be a whole new thin film deposition technique. Unlike other conventional thin film deposition processes, the individual deposition particles carry its own ion beam energies which are directly coupled for the formation of this films. Due to the nature of ion beams, the energies can be controlled precisely and eventually can be tuned for optimizing the process. SKION's negative C- ion beam source is used to investigate the initial nucleation mechanism and growth. Strong C- ion beam energy dependence has been observed. Complete phase control of sp3 and sp3, control of the C/SiC/Si interface layer, control of crystalline and amorphous mode growth, and optimization of the physical properties for corresponding applications can be achieved.

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Statistical Modeling of Pretilt Angle Control using Ion-beam Alignment on Nitrogen Doped Diamond-like Carbon Thin Film

  • Kang, Hee-Jin;Lee, Jung-Hwan;Han, Jung-Min;Yun, Il-Gu;Seo, Dae-Shik
    • Transactions on Electrical and Electronic Materials
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    • v.7 no.6
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    • pp.297-300
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    • 2006
  • The response surface modeling of the pretilt angle control using ion-beam (IB) alignment on nitrogen doped diamond-like carbon (NDLC) thin film layer is investigated. This modeling is used to analyze the variation of the pretilt angle under various process conditions. IB exposure angle and IB exposure time are considered as input factors. The analysis of variance technique is settled to analyze the statistical significance, and effect plots are also investigated to examine the relationships between the process parameters and the response. The model can allow us to reliably predict the pretilt angle with respect to the varying process conditions.

TOF-MEIS System을 이용한 Ultra Thin Film 및 Composition and the Core/Shell Structure of Quantum Dot 분석

  • Jeong, Gang-Won;Kim, Jae-Yeong;Mun, Dae-Won
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.08a
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    • pp.284-284
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    • 2013
  • 중 에너지 이온 산란 분석법(Medium Energy Ion Scattering Spectrometer, MEIS)은 50~500 keV로 이온을 가속 후 시료에 입사시켜 시료의 원자와 핵간 충돌로 산란되는 일차이온의 에너지를 측정하여 시료를 분석하는 기법으로, 원자층의 깊이 분해능으로 초박막의 표면 계면의 조성과 구조를 분석 할수 있는 유용한 미세 분석기술이다. 본 실험에서 에너지 70~100 keV의 He+ 이온을 사용하여 Pulse Width 1 ns의 Pulsed ion beam을 만들어 Start 신호로 사용하고 Delay-line-detector에 검출된 신호를 End 신호를 이용한 TOF-MEIS System을 개발하였다. 활용 가능한 분석시편으로 Ultra thin film 시편으로 1, 1.5, 2, 2.5, 3, 4 nm의 HfO2, 1.8, 4nm의 SiO2 시편을 분석 하였으며 Ultra Shallow Junction 시편으로 As Doped Si, Cs Doped Si 시편 및 Composition, Core/shell 구조의 Q-dot 시편으로 CdSe, CdSe/ZnS등 다양한 분석 실험을 진행 하였다. Composition, Core/shell 구조의 Q-dot 시편은 Diamond Like Carbon(DLC)의 Substrate에 Mono-layer로 형성하여 분석하였다.

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Crack Face Friction Effects on Mode II Stress Intensities for a Surface-Cracked Coating In Two-Dimensional Rolling $Contact^{\copyright}$ (구름접촉 하중시 코팅 표면에 발생한 균열면의 마찰을 고려한 모드II 전파거동에 관한 연구)

  • Moon Byung-Young;Kim Byeong Soo
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.6 s.171
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    • pp.159-167
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    • 2005
  • This work focuses on the effects of crack free friction on Mode II stress intensity factors, $K_{II}$, for a vertical surface crack in a two-dimensional finite element model of TiN/steel subject to rolling contact. Results indicate that maximum $K_{II}$ values, which occur when the load is adjacent to the crack, may be significantly reduced in the presence of crack face friction. The reduction is more significant for thick coatings than for thin. Crack extension and increased layer thickness result in increased $K_{II}$ values. The effect of crack face friction on compressive $K_I$ values appears negligible. Comparative results are presented for $MoS_2/steel$ and diamond-like carbon(DLC)/Ti systems.

Effects of Changes in Accelerated Degradation Conditions for Catalyst Supports in Polymer Electrolyte Fuel Cell (고분자전해질 연료전지(PEMFC)에서 촉매 지지체 가속 열화 조건 변화의 영향)

  • Sohyeong Oh;Yuhan Han;Donggeun Yoo;Myoung Hwan Kim;Ji Young Park;Youngjin Choi;Kwonpil Park
    • Korean Chemical Engineering Research
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    • v.62 no.1
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    • pp.7-12
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    • 2024
  • The durability of the catalyst support has a significant effect on the durability of proton exchange membrane fuel cells (PEMFC). The accelerated durability evaluation of the catalyst support is performed at a high voltage (1.0 to 1.5 V), and the catalyst and ionomer binder in the catalyst layer are also deteriorated, hindering the evaluation of the durability of the support. The existing protocol (DOE protocol) was improved to find conditions in which the support, which is a durability evaluation target, deteriorates further. A protocol (MDOE) was developed in which the relative humidity was lowered by 35% and the number of voltage changes was reduced. After repeating the 1.0 ↔ 1.5 V voltage change cycle, the catalyst mass activitiy (MA), electrochemical active area (ECSA), electrical double layer capacity (DLC), Pt dissolution and particle growth were analyzed. Reaching 40% reduction in mass activity, the MDOE protocol took only 500 cycles, reducing the number of voltage changes compared to the DOE method and increasing the degradation of the carbon support by 50% compared to the DOE protocol.

Effect of $Cl_2$ Gas Concentration of the Surface Modified TiC on the Tribological Properties (TiC표면개질에서 $Cl_2$ 가스농도가 tribology 특성에 미치는 효과)

  • Bae, Heung-Taek;Lim, Dae-Soon;Na, Byung-Chul
    • Tribology and Lubricants
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    • v.23 no.6
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    • pp.261-265
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    • 2007
  • Carbide-derived carbon coating has been synthesized by low temperature treatment of TiC disk with $H_2/Cl_2$ mixture gases. A variety of physical measurements indicated that Ti was extracted and carbon layer was formed by exposure of $Cl_2$ gas. The $I_D/I_G$ ratio increased with increasing $Cl_2$ gas concentration. Wear coefficient and frictional coefficient varied with $Cl_2$ gas concentration. When the $Cl_2$ gas concentration decreased to 3.3 vol%, the friction coefficient approach a minimum. The results showed that degree of graphite crystallinity and variation of porosity due to the $Cl_2$ gas content were responsible for different tribology performance.

Statistical modeling of pretilt angle control for NLC using ion beam alignment (이온빔 배향을 이용한 네마틱 액정의 프리틸트각 제어를 위한 통계적 모델링)

  • Kang, Hee-Jin;Kang, Dong-Hun;Lee, Jung-Hwan;Yun, Il-Gu;Oh, Yong-Cheul;Seo, Dae-Shik
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.11a
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    • pp.302-303
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    • 2006
  • The response surface modeling of the pretilt angle control using ion-beam (IB) alignment on nitrogen doped diamond-like carbon (NDLC) thin film layer is investigated. The response surface model is used to analyze the variation of the pretilt angle under various process conditions IB exposure angle and IB exposure time are considered as Input factors. The analysis of variance technique is used to analyze the statistical significance, and effect plots are also investigated to examine the relationships betweenthe process parameters and the response. The model can allow us to reliably predict the pretilt angle with respect to the varying process conditions.

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Comparison of Catalyst Support Degradation of PEMFC Electrocatalysts Pt/C and PtCo/C (PEMFC 전극촉매 Pt/C와 PtCo/C의 촉매 지지체 열화비교)

  • Sohyeong Oh;Yoohan Han;Minchul Chung;Donggeun Yoo;Kwonpil Park
    • Korean Chemical Engineering Research
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    • v.61 no.3
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    • pp.341-347
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    • 2023
  • In PEMFC, PtCo/C alloy catalysts are widely used because of good performance and durability. However, few studies have been reported on the durability of carbon supports of PtCo/C evaluated at high voltages (1.0~1.5 V). In this study, the durability of PtCo/C catalysts and Pt/C catalysts were compared after applying the accelerated degradation protocol of catalyst support. After repeating the 1.0↔1.5V voltage change cycles, the mass activity, electrochemical surface area (ECSA), electric double layer capacitance (DLC), Pt dissolution and the particle growth were analyzed. After 2,000 cycles of voltage change, the current density per catalyst mass at 0.9V decreased by more than 1.5 times compared to the Pt/C catalyst. This result was because the degradation rate of the carbon support of the PtCo/C catalyst was higher than that of the Pt/C catalyst. The Pt/C catalyst showed more than 1.5 times higher ECSA reduction than the PtCo/C catalyst, but the corrosion of the carbon support of the Pt/C catalyst was small, resulting in a small decrease in I-V performance. In order to improve the high voltage durability of the PtCo/C catalyst, it was shown that improving the durability of the carbon support is essential.