• Title/Summary/Keyword: Tribology

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Wear Behaviours and Material Characteristics of TiN Coatings (CAE에 의한 TiN 증착층의 특성 및 마모거동에 관한 연구)

  • Song, Gun;Yoon, Eui-Sung;Ahn, Hyo-Sok
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1991.11a
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    • pp.38-43
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    • 1991
  • 일반 금속재료로써 표면층이 최적의 tribology적 성질을 갖도록 하기에는 한계점이 있으며, 이러한 문제점을 해결하기 위한 수단으로 bulk material에 그것이 갖지 못하는 tribology적으로 우수한 성질을 그 표면층에 부여하는 기술로 여러가지 방법이 개발되어 왔으며 그 중 대표적인 것이 표면코팅기술이다. 표면 코팅기술중에서도 세라믹코팅기술이 최근에 들어 최고의 관심사가 되고 있는데 이는 세라믹재의 특징이 고강도, 고경도, 내산화성 및 내화학적 성질 등 기계 요소가 받는 가혹한 조건에 최적의 내성을 지니기 때문이다. 특히 세라믹재가 갖는 고강도, 고경도의 성질은 마찰, 맘모 특성의 향상을 극대화시킬 수 있기 때문에 마찰, 마모가 문제시되는 기계요소에의 적용전망은 매우 밝으며, 특히 취약한 환경 즉, nuclear industry와 우주산업 등과 같이 재래의 윤활기술이 제대로 적용될 수 없는 분야에 세라믹코팅기술의 응용은 절대적으로 필요하다. 현재 세라믹 재료의 마찰과 마모특성에 대한 연구는 전 세계적으로 비교적 활발히 진행되고 있으나 세라믹 코팅으로서의 세라믹재의 마찰, 마모특성에 대한 연구는 아직 초보단계에 있다고 할 수 있다. 따라서 본 연구에서는 현재 응용범위를 넓혀가고 있는 TiN을 cathodic arc evporation(CAE)-기술을 이요하여 모재에 코팅을 하여 그 증착층의 재료적 특성 및 마모특성에 대하여 고찰하였다.

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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.

Experimental Study on Friction Characteristics of Pb-free Pin Bushing for an Internal Combustion Engine (내연기관용 무연 핀부싱의 마찰특성에 관한 실험적 연구)

  • Kim, Chung-Kyun;Oh, Kyoung-Seok
    • Tribology and Lubricants
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    • v.23 no.6
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    • pp.306-311
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    • 2007
  • This paper presents the friction characteristics of pb-fres pin bushing bearings for an automotive gasoline engine. The external load is 100 N to 600 N and the speed of the pin bushing bearing is 1000 rpm to 3000 rpm against the rubbing surfaces. And the contact modes of rubbing surfaces between a piston pin and a pb-free pin bushing specimen are a dry friction, an oil lubricated friction and a mixed friction that is starved by a lack of engine oil. Two influential factors of a contact rubbing modes and a material property are very important parameters on the tribological performance of a friction characteristic between a piston pin and a pb-free pin bushing. The experimental result shows that the pin bushing speed of 2000 rpm shows a typical oil film lubricated sliding contact mode in which means that as the applied load is increased, the friction loss is increasing. But other contact mode depending on the speed and the load may affect to the fiction coefficient without a regular and uniform trend. In summary, the oil lubricated rubbing surface definitely decreases a running-in period in short and increase oil film stiffness, and this may leads the reduction of a friction loss.

Experimental Study of Braking Friction and Wear Characteristics of Disk Brake (디스크 브레이크의 제동마찰 및 마멸특성에 관한 실험적 연구)

  • Kim Chung-Kyun;Lee Boung-Kwan;Kim Han-Goo
    • Tribology and Lubricants
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    • v.22 no.3
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    • pp.149-154
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    • 2006
  • This paper presents the braking friction and wears on the rubbing surfaces of a friction pad-disk brake. In this study, four friction disk specimens are sampled from unused and used disks in which are taken from the disk brake system when the friction induced vibration and noise problems have been occurred during a braking period at a running period of 10,000 km, 20,000 km, and 30,000 km in random. The experimental results indicate that the tribological characteristics of an unused disk brake shows equal and stable as a friction coefficient and temperature distributions during a braking friction/wear test period including a total friction mode from the start to running periods. But the used disk brake shows unstable and uneven friction modes between an outside and inside rubbing surfaces of a disk brake in terms of a friction coefficient and wears. This may lead to a friction induced friction vibration and noise problems of a used disk brake.

A Study on the Structural Stiffness and Coulomb Damping of Air Foil Bearing Considering the Interaction among Bumps (범프들의 상호작용을 고려한 공기 포일 베어링의 구조적 강성 및 쿨롱 감쇠에 대한 연구)

  • Lee, Yong-Bok;Park, Dong-Jin;Kim, Chang-Ho
    • Tribology and Lubricants
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    • v.22 no.5
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    • pp.252-259
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    • 2006
  • Air foil bearing supports the rotating journal using hydrodynamic force generated at thin air film. The bearing performances, stiffness, damping coefficient and load capacity, depend on the rotating speed and the performance of the elastic foundation, bump foil. The main focus of this study is to decide the dynamic performance of corrugated bump foil, structural stiffness and Coulomb damping caused by friction between bump foil and top foil/bump foil and housing. Structural stiffness is determined by the bump shape (bump height, pitch and bump thickness), dry-friction, and interacting force filed up to fixed end. So, the change of the characteristics was considered as the parameters change. The air foil bearing specification for analysis follows the general size; diameter 38.1 mm and length 38.1 mm (L/D=1.0). The results show that the stiffness at the fixed end is more than the stiffness at the free end, Coulomb damping is more at the fixed end due to the small displacement, and two dynamic characteristics are dependent on each other.

An Experimental Study on the Measurement of Soot Contamination in A Diesel Engine Oil (디젤 엔진오일 내 Soot 함량 증가에 따른 오염도 측정에 관한 실험적 고찰)

  • Jo, Seong-Yong;Gong, Ho-Seong;Yun, Ui-Seong;Han, Heung-Gu;Jeong, Dong-Yun
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2002.05a
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    • pp.120-129
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    • 2002
  • New method and device for the on-line measurement of soot concentration in a diesel engine oil are proposed, where the measurement principle is based mainly on attenuated internal total reflection. Various laboratory tests of the detector were performed mainly with carbon black particles of different contamination levels. It was found that the proposed detector could be well used to monitor oil deterioration due to soot contamination. Operational range of the detector was found from 0 to 5 mass percentage of soot content. Test results with water and fuel dilution showed that these effects were not remarkable. However, adsorption of carbon black particles to a measurement surface was considered to be a critical problem in the new detector. Effects of particle deposition onto the interface was experimentally evaluated with the oil temperature and turbulence and discussed throughout this work.

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An Experimental Study on the Micro Friction and Wear Characteristics of Organically Modified Hybrid Ceramic Materials by A Sol-Gel Process (졸-겔 공정에 의한 유기변성 하이브리드 세라믹 물질의 미세 마찰마모 특성)

  • Han, Hung-Gu;Kong, Ho-Sung;Yoon, Eui-Sung;Yang, Seung-Ho
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2002.05a
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    • pp.215-225
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    • 2002
  • In order to enhance the thermal stability of binder materials of bonded type solid lubricants, several combinations of metal-alkoxide based sol-gel materials such as methyltrimethoxysilane(MTMOS), $titaniumisopropoxide(Ti(Opr^{j})_{4})$, $zirconiumisopropoxide(Zr(Opr^{j})_{4})$ and $aluminumbutoxide(Al(Obu^{t})_{4})$ were chemically modified by epoxy-, acrylic- and fluoro-silane compounds, respectively, in this work. Friction and wear characteristics of these hybrid ceramic materials were tested with a micro tribe-tester where a reciprocating steel ball slid on a test material, and the tribological property was also evaluated with respect to both heat-curing temperature and tile time. Test results generally showed that hybrid ceramic materials modified by epoxy-silane compounds had a low friction compared to others. And the higher heat-curing temperature and the longer heat treatment time resulted in the higher friction and the lower wear. IR spectroscopic analyses revealed that it was caused mainly by the increased metal oxide content in hybrid ceramics when the heat-curing temperature was over $320^{\circ}C$.

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