• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.44-44
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• 1998

It was observed that the friction coefficient decreased with increasing Si concentration in the l ilms. Furthermore, the friction behavior became more s때ble even when very small amount of S Si of less than 0.5 at. % was incorporatA:회 By analyzing the composition of the debris f formed, we could show that the low and stabilized friction coefficient is in마nately relatA:었 w with the formation of the Si rich oxide debris. These result supports the mechanism that the h hydrated silica debris is the reason for low friction coefficient in humid environment. Second e evidence of the role of Si rich oxide debris could be found in the triOO-chemical reactions d during initial stage of triho-test. When the Si concen$\sigma$ation was less than 5 at.%, initial t transient period of high friction coefficient was commonly observed. Mter the transient period, m the friction coefficient becomes lower with increasing contact cycles. The initial $\sigma$ansient p peri여 becomes shorter and the starting and maximum friction coefficients in $\sigma$ansient 야,riod d decreased with increasing Si concentration. Composition of the debris on the wear scar s surface was analyzed by Auger spe따'Oscopy at v뼈ous stages in the initial transient period. W We observed that when the friction coefficient increased in earlier stage of the $\sigma$'ansient p period, iron and oxygen was observed in the debris. However, decrease in the 당iction c coefficient in the later stage of the transient period was associated with the formation of s silicon rich oxide debris. This result also supports the friction mechanism of Si-DLC films t that the formation of Si rich oxide debris results in low friction coefficient in ambient a atmosphere. atmosphere.

• Journal of the Korean Vacuum Society
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• v.9 no.4
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• pp.328-334
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• 2000

DLC (Diamond-Like Carbon) films were deposited by ECR-PECVD (electron cyclotron resonance plasma-enhanced chemical vapor deposition) method with the variation of substrate bias voltage under the others are constant except it. We have investigated the ion bombardment effect induced by the substrate bias voltage on films during the deposition of film. The characteristics of the film were analyzed using the Dektak surface profiler, SEM, FTIR spectroscopy, Raman spectroscopy and Nano Indentation tester. FTIR spectroscopy analysis shows that the amount of dehydrogenation in films was increased with the increase of substrate bias voltage and films thickness was decreased. Raman scattering analysis shows that integrated intensity ratio $(I_D /I_G)$ of the D and G peak was increased as the substrate bias voltage increased, and films hardness was increased. From these results, it can be concluded that films deposited at this experimental have the enhanced characteristics of DLC because of the ion bombardment effect on films during the deposition of film.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.159-160
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• 2002

To investigate the humidity effect on tribological behaviors of Si-DLC/DLC multi-layers, the samples were prepared using a system consisted of an ion-gun for deposition DLC films and a balanced magnetron sputter for introducing silicon atoms to Si-DLC films. The Si-DLC/DLC multi-layers were composed of pure DLC films and Si-incorporated DLC films alternatively and had different bilayer numbers. Hardness and residual stress were drastically decreased through the formation of Si-DLC/DLC multi-layers compared to those of the pure and Si-incorporated DLC films. Wear results obtained under the various humidity conditions (<10%, $40{\sim}50%$, and >85%) showed that the pure DLC film was largely depended on the humidity while the Si-DLC and the Si-DLC/DLC multi-layers were little affected by the environmental humidity. Although friction coefficients of all samples were increased with the relative humidity, the multi-layer films showed relatively lower friction coefficients that those of the single films.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.5
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• pp.197-205
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• 2015

The Diamond Like Carbon(DLC) films for the Electro Optical Tracking System(EOTS) by using Plasma Enhanced Chemical Vapor Deposition(PECVD) method is presented. We achieve that the DLC films can reduce the surface delamination of thermal observation sensor front window due to the high hardness, low friction and chemical inertness which is comparable to a Si film. According to our experiment results, DLC films can be used for various electro optical systems to eliminate surface delamination.

• Design & Manufacturing
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• v.6 no.1
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• pp.24-28
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• 2012

Friction and wear affect all processes involved in the extraction of materials and their conversion into finished products in the die applications such as drawing, extrusion etc. Originating phenomenon from the contact surface between the tool and workpiece, they are usually a hindrance to materials process operations which usually result in damaging the tools, increasing energy consumption, the contamination of processed material by wear particles and also some problems associated with technologies to control friction and wear. The most well established method to control friction and wear is by the application of lubricant such as fluorocarbon. Besides, a surface technique so-called surface modification can be applied to solve the tribology problems of the die applications for both the economical and ecological reasons. In this article, we applied DLC(diamond-like carbon) thin film on alumina ceramic for HT test using the PIID(plasma ion immersion deposition), 4 groups of test specimens were tested up to $200^{\circ}C$ which is a little higher than the normal working temperature of die application. Pin-on-disc tribo-tester was used to test the friction and surfaces were characterized by SEM and EDS and else, the morphology changes of DLC coatings were studied. The present work indicated that the DLC had a great potential to reduce the friction and wear in the alumina die application without lubricants.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.4
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• pp.123-130
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• 2013

Zirconia is well known in industrial applications for its mechanical characteristics. DLC (diamond-like carbon) have high elastic modulus, high electric resistivity, high dielectric constant, high wear resistance, low friction coefficient, bio compatibility, chemically inert and thermally stable. Because of all these physical and chemical properties these types of coatings have become key procedure for thin coating. Friction coefficient of DLC films is already evaluated and the current work is a further advancement by calculating the fracture toughness and wear resistance of these coatings. In the present study DLC thin film coatings are developed on $ZrO_2$ alloy surface using Plasma Enhanced Chemical Vapor Deposition (PECVD) method. Vicker hardness test is employed and it was concluded that, DLC coatings increase the Vickers hardness of ceramics.

• 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.

• Journal of Integrative Natural Science
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• v.13 no.3
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• pp.87-91
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• 2020

Molybdenum carbide (MoC_x) thin films (TFs) were deposited by reactive radio frequency (rf) magnetron co-sputtering in high vacuum chamber. We compared the properties of MoC_x thin films as the rf power changed on C target. The result of alpha step measurement showed that the thickness of the MoC_x TFs varied from163.3 to 194.86 nm as C power was increased from 160 to 200 W. The crystallinity of MoC_x such as b-Mo₂C, Mo₂C, and diamond like carbon (DLC) structures were observed by XRD. The oxidation states of Mo and C were determined using high resolution XPS spectra of Mo 3d and C 1s were deconvoluted. Molybdenum was consisted of Mo, Mo⁴⁺, and Mo⁶⁺ species. And C was deconvoluted to C-Mo, C, C-O, and C=O species.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.185-189
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• 2005

We reported here nano-scale electrical phase-change recording in amorphous $Ge_2Sb_2Te_5$ media using an atomic force microscope (AFM) having conducting probes. In recording process, a pulse voltage is applied to the conductive probe that touches the media surface to change locally the electrical resistivity of a film. However, in contact operation, tip/media wear and contamination could major obstacles, which degraded SNR, reproducibility, and lifetime. In order to overcome tip/media wear and contamination in contact mode operation, we adopted the W incorporated diamond-like carbon (W-DLC) films as a protective layer. Optimized mutilayer media were prepared by a hybrid deposition system of PECVD and RF magnetron sputtering. When suitable electrical pulses were applied to media through the conducting probe, it was observed that data bits as small as 25 nm in diameter have been written and read with good reproducibility, which corresponds to a data density of $1 Tbit/inch^2$. We concluded that stable electrical phase-change recording was possible mainly due to W-DLC layer, which played a role not only capping layer but also resistive layer.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.10a
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• pp.177-178
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• 2009

DLC (Diamond-like Carbon) 코팅막은 저마찰, 고경도, 낮은 표면조도 등의 우수한 특성을 갖는 박막 물질로 다양한 산업분야에서 그 코팅막의 활용을 목적으로 응용연구가 활발하게 이루어지고 있다. 본 연구에서는 플라즈마 화학기상증착(PCVD) 공정을 이용하여 바이어스, 진공도, 공정 온도 등의 코팅 조건 변수를 이용하여 DLC 코팅막을 제작하였다. 또한, 코팅막은 공정 조건에 따라 증착속도, 표면 및 단면 조직, 밀착력, 경도, 마찰계수 등의 특성을 평가하였다. 플라즈마 화학기상증착법을 이용한 DLC 코팅막 제조는 상온과 $175^{\circ}C$에서 이루어졌으며, 저온 중 DLC 코팅막 제조가 가능해짐에 따라 고분자 와 같은 저융점을 갖는 피처리물의 코팅처리가 가능하여 산업적 응용의 확대가 기대된다. SEM 표면 조직 관찰에 따른 DLC 코팅막의 표면조직과 조도는 공정조건에 따라 큰 차이는 보이지 않았지만, 밀착력에 있어서는 매우 큰 차이를 나타내었다. 스크래치 시험 결과 가장 높은 밀착력은 100 N 이상을 나타내었으며, 이 때의 마찰계수는 약 0.02를 나타내었다. 가장 낮은 마찰계수는 약 0.01을 보였으며, 이때의 밀착력은 25 N을 나타내었다. 증착속도는 바이어스 전압의 증가에 따라 증가하는 경향을 나타내었으며, 온도의 증가에 따라 감소하는 경향을 나타내었다.