• Journal of the Korean Society for Railway
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• v.15 no.3
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• pp.224-230
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• 2012

The wearing slider of the rail motor car's pantograph is considerable changed by the type and the material properties. Especially, precipitation and arc influences are main factors decided to life time of wearing slider and contact wire. This study is wearing phenomenon analysis of Cu-type wearing slider with high electric conductivity and resistance arc through experiment by running train. Author observed that wearing phenomenon of Cu-type wearing slider with normal and abnormal wearing characteristics and comparatively analysis precipitation, mileage and weight influences of exchanged Cutype and Fe-type wearing sliders. In this paper result showed that necessity for the application which is the Fe-type of wearing slider had superior wear resisting capacity etc., through tribology approach.

• Composites Research
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• v.23 no.2
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• pp.10-16
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• 2010

$Al_2O_3$ fiber and SiC particle hybrid metal matrix composites (MMCs) were manufactured by squeeze casting method investigated for their tribological properties. The pin specimens had different ratios of fiber to particle content but their total weight fraction was constant at 20 wt. %. Tribological tests were performed with a pin-on-disk friction and wear tester. The investigation of the dry tribological characteristics of hybrid MMCs were carried out at room temperature and elevated temperature of$100^{\circ}C$ and$150^{\circ}C$. The morphologies of worn surfaces were examined by scanning electron microscope (SEM) to observe tribological characteristics and investigate wear behavior. The results revealed that the wear resistance improved with the content of SiCp increased of the planar random (PR) MMCs at room temperature. At the elevated temperature, it revealed that the wear resistance of normal (N) MMCs was superior to that of the PR-MMCs due to PR-fibers were easily pulled out holistically from the worn surface. Meanwhile, the coefficient of friction decreased with the temperature increasing.

• Composites Research
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• v.16 no.3
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• pp.75-84
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• 2003

The purpose of this study is to investigate the wear properties of Saffil/Al, Saffil/A12O3/Al and Saffil/SiC/Al hybrid metal matrix composites fabricated by squeeze casting method. Wear tests were done on a pin-on-disk friction and wear tester under both dry and lubricated conditions. The wear properties of the three composites were evaluated in many respects. The effects of Saffil fibers, $\textrm{Al}_2\textrm{O}_3$ particles and SiC particles on the wear behavior of the composites were investigated. Wear mechanisms were analyzed by observing the worn surfaces of the composites. The variation of coefficient of friction(COF) during the wear process was recorded by using a computer. Under dry sliding condition, Saffil/SiC/Al showed the best wear resistance under high temperature and high load, while the wear resistances of Saffil/Al and Saffi1/$\textrm{Al}_2\textrm{O}_3$/Al were very similar. Under dry sliding condition, the dominant wear mechanism was abrasive wear under mild load and room temperature, and the dominant wear mechanism changed to adhesive wear as load or temperature increased. Molten wear occurred at high temperature. Compared with the dry sliding condition, all three composites showed excellent wear resistance when lubricated by liquid paraffin. Under lubricated condition, Saffil/Al showed the best wear resistance among them, and its COF value was the smallest. The dominant wear mechanism of the composites under lubricated condition was microploughing, but microcracking also occurred to them to different extents.

• Elastomers and Composites
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• v.46 no.1
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• pp.70-77
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• 2011

A new piece of test equipment, the slurry wear tester (SWT), was proposed in this study to evaluate the wear behavior of rubber vulcanizate in environmental contact with slurry. Natural rubber (NR) and chloroprene rubber (CR) were chosen as the basic matrices to test the slurry wear. The fluids used to fill the chamber of the SWT were 35% HCl and NaCl solution. The Akron abrasion test was used for comparison with SWT. According to the results of the Akron abrasion test, CR vulcanizate abraded more rapidly than NR vulcanizate under same test condition. It was found that the hysteresis of rubber was key factor contribute to the wear behavior. However, the slurry wear rate of the NR and CR vulcanizates did not change significantly, even with changes in the concentration of acid and the immersion time in both HCl and NaCl solutions; the fluid decreased the friction between the abrasive paper and the specimen. It also reduced the heat generated from repeated deformation and wear debris at the surface of the SWT's abrasion arm. Thus, these phenomena affected the wear behavior of rubber vulcanizate and caused different results in the conventional Akron abrasion test. This outcome could have resulted in an incorrect analysis if the slurry wear behavior of the rubber vulcanizate was estimated by the conventional abrasion tests, which are operated under dry conditions.

• Tribology and Lubricants
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• v.1 no.1
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• pp.20-29
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• 1985

많은 윤활 부품의 성능과 수명은 초기작동기간에 금속표면에서 일어나는 현상들에 의하여 좌우된다. 특히 혼합마착구역(Mixed film region)에서나 윤활막의 두께가 몇십 마이크론의 정도가 되는 EHD(Elastohydrohynamic)윤활구역에서 작동하는 경우엔 더욱 중요하다. 이러한 경험적 현상에 의해 상대운동하는 두마찰면의 초기 작동과정을 길들이기(run-in, breaking-in)라고 부르고 "마찰 부분의 형상이나 마모 및 윤활 마찰특성이 향상되어가는 과정" 으로 정의한다. 보통 길들이기 과정이 끝나면 표면 모양은 더이상 변하지 않고 마모나 마찰 특성이 일정하게되며 이 단계를 정상 상태라고 부른다. 길들이기과정이 중요시되는 것은 이 과정에서 마모는 정상 상태보다 심하고 Scuffing 혹은 Scoring현상이라고 부르는 마찰면 손상의 가능성이 항상 존재하기 때문이다. 이 현상은 보통의 마모나 부식 또는 피로파손의 형태와는 달리 갑작스런 발생으로 부품이나 기관의 부분적 혹은 완전 파손을 유발함으로써 설계나 제조 과정에 문제를 제기하는 요인으로 오래전부터 알려져 왔다.부터 알려져 왔다.

• Proceedings of the Korean Reliability Society Conference
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• 2006.05a
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• pp.381-383
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• 2006

최근, 선진국에서는 $Rukaflex^{(R)}$라는 새로운 구조의 웨빙을 개발하여, normal usage marks를 감소시키고, 웨빙의 품질을 향상시키려는 경향을 보인다. 기존의 웨빙은 멀티 필라멘트가 경/위사 방향으로 교차되는 구조를 갖는 소폭직물인데, 새로운 구조의 $Rukaflex^{(R)}$는 위사방향에 멀티 필라멘트와 모노 필라멘트를 동시에 사용하여 탄성률(resilience)을 높여서 구조 안정성을 항상시킨 형태의 웨빙이다. 본 연구에서는 $Rukaflex^{(R)}$ 웨빙의 수명을 구조개선 및 마모특성 향상을 통하여 50% 이상 향상시켰는데, 기존 웨빙과 초기 인장강도에서는 차이가 나지 않았으나 활성화 에너지, 형상모수, $B_{10}$ 수명이 증가한 것을 확인할 수 있었다. 이는, 척도모수에서는 기존 웨빙과 근소한 차이를 보이나 구조개선에 의한 마모특성 향상에 의하여, 균일한 마모 및 degradation 특성을 나타내므로, $B_{10}$ 수명이 향상된 것을 확인할 수 있었다.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.4
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• pp.344-350
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• 2004

This is the study on dry sliding wear behavior of unidirectional carbon fiber reinforced epoxy matrix composite at ambient temperature. The wear rates and friction coefficients against the stainless steel counterpart specularly processed were experimentally determined and the resulting wear mechanisms were microscopically observed. Three principal sliding directions relative to the dominant fiber orientation in the composite wear selected. When sliding took place against smooth and hard counterpart, the highest were resistance and the lowest friction coefficient were observed in the antiparallel direction. When the velocity between the composite and the counterpart went up, the wear rate increased. The fiber destruction and cracking caused fiber bending on the contact surface, which was discovered to be dominant wear mechanism.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.4
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• pp.337-343
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• 2004

This paper presents an experimental study of friction and wear properties of a unidirectional oriented continuous crbon-fiber reinforced epoxy composite at the ambient temperature. Friction and wear experiments were conducted in the three principal sliding direction of the fiber orientation in the composite were selected against the stainless steel counterpart specularly processed were using a pin -on-disc apparatus. Friction coefficient and specific wear rate at various normal loads and sliding velocities wear determined. When sliding took place against smooth and hard counterpart, the hightest were resistance and the lowest friction coefficient were observed in the anti-parallel direction. The wear track of the worn specimens was examined with a scanning electron microscope(SEM) to observe the damaged fibers on the surface. In addition, SEM observations of the worn surfaces allowed to identify the involved different wear mechanisms.

• 대한치과보철학회:학술대회논문집
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• 1995.12a
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• pp.39-40
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• 1995

• Tribology and Lubricants
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• v.1 no.1
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• pp.38-45
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• 1985

Ferrograms prepared from off samples collected during testing in the transition region were originally diluted at 20:1. To obtain some information about the effect of dilution on the analysis procedures, a series of measurements were made on ferrograms prepared to different dilutions in the range 6 to 30:1 from oil samples collected after testing in the four ball machine at the 51 kg and 55 kg load, respectively, Fig. 1. The variations in area covered, perimeter, intercept and particle count were then plotted as a function of dilution level and appropriate mathematical expressions established such that the results obtained at any dilution level specified within the range can then be corrected back to an equivalent undiluted value. The effect of dilution on the variance of the particle size distribution was also investigated. The main results are tabulated, Tables 1-5 and also plotted as a function of dilution, level Figs. 2-9.