• Title/Summary/Keyword: worn surface

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Wear Properties of Vegetable Oils Formulated with Some Antiwear Additives (내마모첨가제가 첨가된 식물성유의 마모특성연구)

  • 최웅수;안병길;정용진;권오관
    • Tribology and Lubricants
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    • v.12 no.3
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    • pp.6-11
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    • 1996
  • There has been a growing concern for the use of mineral oil based lubricants because of the worldwide interest in environmental issues. This has prompted the use of vegetable oils as more environmentally acceptable base fluids. In view of this, four-ball wear test was carried out to investigate the tribological behavior of selected vegetable oils blended with ZDDP, TCP and DBP under high speed and temperate conditions. Of the additive evaluated, the new additive, DBP has provided antiwear performance superior to the two other additives more commonly used. This superior performance by DBP is probably caused by different wear mechanism. This wear mechanism has been evidenced by the surface analysis of worn balls conducted using optical microscope and EDAX.

High Temperature Wear Behavior of Plasma-Sprayed Zirconia-Alumina Composite Coatings (플라즈마 용사된 알루미나-지르코니아 복합체의 고온 마모.마찰 거동)

  • 김장엽;임대순;안효석
    • Tribology and Lubricants
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    • v.12 no.3
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    • pp.33-38
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    • 1996
  • High temperature wear behaviors of plasma-sprayed ZrO$_{2}$-$Y_{2}O_{3}$ composite coatings were investigated for high temperature wear resistance applications. The composite powders containing 20, 50, 80 vol% of alumina for plasma spray were made by spray drying method. Wear tests with composite coated specimens were performed at temperature ranges from room temperature to 800$^{\circ}$C. Wear tests were also carried out with heat treated specimens at room temperature. The microstructural change of coatings and the worn surface were examined by SEM and XRD. Sharp increase of wear loss at high temperature wear test was observed in specimens containing 50 and 80 vol% alumina. Similar trend was observed in the heat treated coatings. The measured residual stress was increased with increased alumina contents and heat treating temperatures. Residual stress induced during heat treatment appeared to be responsible to the observed harmful effect of alumina additions on the high temperature wear.

The Effects of the Annealing Temperature and Environments on Room Temperature Wear Behavior of Plasma-Sprayed Partially Stabilized Zirconia Coatings (플라즈마 용사된 부분안정화 지르코니아 코팅의 상온 마모거동에 미치는 열처리온도 및 분위기의 영향)

  • 김장엽;임대순
    • Journal of the Korean Ceramic Society
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    • v.31 no.10
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    • pp.1176-1180
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    • 1994
  • The sliding wear behavior of the plasma-sprayed zirconia containing 3 mol% yttria was investigated after the annealing at room temperature to 80$0^{\circ}C$ in various concentrations of humid atmosphere as laboratory, humid, dry argon atmosphere. Both of the friction coefficient and the wear loss increased with increasing temperature up to 80$0^{\circ}C$. Surface morphology of the worn samples changed with annealing temperature. The change of monoclinic/tetragonal (m/t) x-ray peak intensity ratio effected the wear behavior. The m/t ratio had maximum value at 20$0^{\circ}C$ and decreased with increased temperature in laboratory and humid atmosphere. In argon atmosphere the m/t ratio had no maximum value and decreased with increasing temperature. At all the annealing temperature humid atmosphere had more the m/t ratio value than any other atmosphere. The change of toughness was showed the inversed result of m/t ratio change. The results indicated that the resudial stress which was induced by the different amount of phase transformation takes a detrimental role in wear behavior.

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A Study on the Material Properties of Grey Cast Iron for Cylinder Liner Treated by Thermo Plastic Deformation Process (열소성변형공정을 시행한 회주철제 실린더 라이너의 재료물성에 관한 연구)

  • Kim Tae-Hyoung;Kim Jong-Ho
    • Journal of Advanced Marine Engineering and Technology
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    • v.29 no.6
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    • pp.671-677
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    • 2005
  • In internal combustion engines the usual material for the cylinder liner is because of its good wear resistance Apparently this wear resistance arises from the at iron to form a hard glazed surface when under sliding friction. When the cylinder liner wear limits, it shall be replace with new one according to the classification soci manufacturer's standards. However, adoption of alternative repairing method such a metalizing, thermo plastic deformation process became inevitable taking enormous cost renewal into consideration. In this paper. the material properties of cylinder liner of grey discussed on the basis of the results of experimental work of the thermo plastic deformation the worn out cylinder liner made of grey cast iron.

Performance of Assembled-type Drills (조립형 드릴의 성능 평가)

  • Yang, Hae-Jeong;Lee, Jai-Hak;Seo, Jeong-Hwan
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.24 no.2
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    • pp.238-243
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    • 2015
  • Recently, the use of assembled-type drills as environmentally friendly products has expanded because the shanks of drills can be reused by replacing the tip when the tools are worn or cut. In addition to their precision and endurable stiffness with respect to the cutting force, assembled-type drills need no stricture because of thermal deformation, which makes replacement easily. In this study, we developed novel assembled-type drills and compared their characteristics, such as the precision, stiffness, and thermal deformation, with those of conventional drills. The new drills exhibited a precision over IT 8 class and no changes in dimensions due to thermal deformation, such that we can change the assembly easily with durability.

Estimation of Nanomechanical Properties of Nanosurfaces Using Phase Contrast Imaging in Atomic Force Microscopy (원자력현미경의 위상차영상을 이용한 나노표면의 미소기계적 특성 평가)

  • Ahn, Hyo-Sok
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.5
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    • pp.115-121
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    • 2007
  • Phase contrast imaging in atomic force microscopy showed a promise as an effective tool for better understanding of micromechanical properties of surfaces at nano scale. A qualitative estimation model for phase contrast images obtained with a tapping mode AFM was developed. This investigation demonstrated the high efficiency of combined analysis of topography and phase contrast images for characterizing nanosurfaces. Phase contrast images allowed estimation of relative stiffness(elastic modulus) of the sample surface. The phase contrast images revealed a significant inhomogeneity of the nano scale worn surfaces. Phase contrast images are also capable of revealing the formation of tribofilms.

A Study on the Scythian Torque

  • Kim, Moon-Ja
    • The International Journal of Costume Culture
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    • v.6 no.2
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    • pp.69-82
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    • 2003
  • The Scythians had a veritable passion for adornment, delighting in decorating themselves no less than their horses and belongings. Their love of jewellery was expressed at every turn. The most magnificent pieces naturally come from the royal tombs. In the area of the neck and chest the Scythian had a massive gold Torques, a symbol of power, made of gold, turquoise, cornelian coral and even amber. The entire surface of the torque, like that of many of the other artefacts, is decorated with depictions of animals. Scythian Torques are worn with the decorative terminals to the front. It was put a Torque on, grasped both terminals and placed the opening at the back of the neck. It is possible the Torque signified its wearer's religious leadership responsibilities. Scythian Torques were divided into several types according to the shape, Torque with Terminal style, Spiral style, Layers style, Crown style, Crescent-shaped pectoral style.

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Effect of Glass Fiber and Graphite on Wear Properties in Tin-Bronze Matrix Composites (유리섬유 강화 청동기지 복합재에서 마모특성에 미치는 유리섬유와 흑연의 영향)

  • 황순홍;김종국;허무영
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1995.10a
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    • pp.181-187
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    • 1995
  • The effet of glass fiber and graphite on the wear properies in tin-bronze alloy matrix composites was studied by a pin-on-disk type wear testing machine. The results obtained from the wear test were analized by SEM observations of worn surfaces of pins and disks and EPMA composition measurments. The amount of wear was devreased as increasing the content of glass fiber in matrix, since the alloy matrix was reinforced by glass fibers. The wear mechanism of the matrix specimen without glass fibers was proved as the contact area delamination. Oxide layer formed on sliding surface led to the increasing wear resistance. Specimens containing graphite particles showed an lubrication effect to counter disks.

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Wear characteristics of plasma sprayed yttria-stabilized zirconia coating as phase transformation (지르코니아 용사코팅의 상변화에 따른 마멸특성)

  • Park, Chan;Chae, Young-Hun;Kim, Seock-Sam
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2001.11a
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    • pp.322-330
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    • 2001
  • The plasma-sprayed 8%Y$_2$O$_3$-Zirconia coating was studied to know the relationship between phase transformation and wear properties after several heat treatment. Wear tests were carried out with ball on disk on 50N, 70N, 90N. The specimen in this study was cast iron and tests were performed on room temperature. The transformation of phase and residual stress was measured by x-ray diffraction method(XRD) and worn surface were observed by SEM.

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Wear Mechanism of Inconel Alloys in Room Temperature Water (물분위기에서의 인코넬 합금의 마멸기구)

  • 이영호;김인섭
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2001.11a
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    • pp.103-108
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    • 2001
  • Wear test has been performed to evaluate the wear mechanism of Inconel alloys against ferritic stainless steels in room temperature water. By means of scanning electron microscopy (SEM), the worn surface and microstructure of subsurface layer have been examined. The wear at steady state conditions result in the formation of 5∼7${\mu}$m thick layers with fragmented microstructure. The thickness of these layers seems to depend on the ability of work hardening and deformation accommodation at the contact areas during wear. Therefore, in room temperature water, the wear rate is closely related with the wear resistance of these fragment microstructure which are generated after severe subsurface deformation.

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