• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1004-1005
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• 2006

The effect of tempering temperature and microstructure on dry sliding wear behavior of quenched and tempered PM with 0.3% graphite and 1-2% Ni steels was investigated. The sintered specimens were quenched from $890^{\circ}C$ and then tempered at $200^{\circ}C$ and $600^{\circ}C$ for 1 hr. Wear tests were carried out on the quenched$\neq$tempered specimens under dry sliding wear conditions using a pin-on-disk type machine at constant load and speed. The experimental results showed that the wear coefficient effectively increased with increasing tempering temperature and decreased with increasing Ni content.

• Proceedings of the KWS Conference
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• 2001.05a
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• pp.245-247
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• 2001

In this study, the effects of dilution on the wear behavior of PTAW (Plasma Transferred Arc Welding) Inconel 625, Inconel 718 and Stellite 6 overlays on Nimonic 80A were investigated. Inorder to evaluate the wear performance, two-body and three-body abrasive wear test, and dry sliding wear test were performed. According to wear tests, the wear rate of deposit with dilution 30% was higher than that of dilution 10% by 10%, and it was also found the plastic deformation near worn surface.

• Carbon letters
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• v.10 no.2
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• pp.97-100
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• 2009

In this work, effects of carbon matrix on sliding friction and wear behavior of four kinds of C/C have been investigated against 40 Cr steel ring mate. Composite A with rough lamination carbon matrix (RL) shows the highest volume loss and coefficient of friction, while composite D with smooth lamination/resin carbon matrix (SL/RC) shows the lowest volume loss. The worn surface of composite A appears smooth, whereas that of composite C with smooth lamination carbon (SL) appears rough. The worn surface of composite D appears smooth under low load but rough under high load. Atomic force microscope images show that the size of wear particles on the worn surface is also dependent on the carbon matrix.

• Tribology and Lubricants
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• v.20 no.2
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• pp.91-96
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• 2004

Wear behavior of self-mated stainless steels in NaCl solution has been investigated. The experiment was done in the corrosive liquid of which NaCl concentration of $0\~3\%$ and temperature of $15\~90^{\circ}C$. Two kinds of wear type were observed: one is 'severe wear' type which shows gradually increasing wear volume with increasing sliding distances, the other is 'mild wear' type which shows change of wear rate from high value to low at transition distance. The specific wear rate in severe wear type was not sensitive to the liquid temperature and concentration of NaCl but stable at value of $1\times10^{-3}\;mm^3$ approximately.

• 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 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.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.10a
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• pp.135-138
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• 2002

The purpose of this study is to investigate the lubricated wear properties of Saffil/Al, Saffil/$Al_2O_3/Al$ and Saffil/SiC/Al hybrid metal matrix composites fabricated by squeeze casting method. Wear tests were done on a pin-on-disk friction & wear tester with long sliding distance. The wear properties of the three composites were evaluated in many respects. The effects of Saffil, $Al_2O_3$ particles and SiC particles on the wear behavior of the composites under lubricated conditions were elucidated. 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. Comparing with the dry sliding condition, all three composites showed excellent wear resistance when lubricated by liquid paraffin. Under intermediate load, Saffil/Al showed best wear resistance among them, and its COF value is the smallest. The dominant wear mechanism of the composites was microploughing, but microcracking also occurred for them to different extent.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.180-184
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• 2004

The tribological behavior of carbon epoxy composites whose surfaces have many small grooves of $100\mu m$ width was experimentally investigated with respect to the sliding direction against groove orientation, surface pressure (P) and velocity (V). The wear mechanism of the composites was observed to calculate the wear volume with respect to the friction coefficient using scanning electron microscopic (SEM). Experimental results show that the abrasive wear is dominant wear mechanism for the grooved composite surface and the friction and wear are greatly reduced when the sliding direction is parallel to the axis of groove because abrasive particles are removed through the grooves effectively.

• Journal of Power System Engineering
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• v.10 no.1
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• pp.46-51
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• 2006

Present study was investigated the effect of the particle of the counterface of unidirectional carbon fiber reinforced composite. The friction coefficient of composite and the specific wear rate different sliding velocity were measured for this materials. The friction track of counterface was observed by an optical microscope and scanning electron microscope. There were insignificant effects of the specific wear rate under lower Sic abrasive particle, however it showed high effect on $30{\mu}m$ abrasive particle size. There were significant effects of friction and wear behavior of the fiber direction under 0.3m/s sliding speed. Major failure mechanisms can be classified such as microfracture, plowing, microcutting, cutting and cracking.

• Journal of Korea Foundry Society
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• v.15 no.6
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• pp.574-587
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• 1995

The $SiC_p-reinforced$ preforms fabricated by spray casting process were hot-extruded and subsequently T6-treated, and the morphology of the silicon phase and the grain size for these preforms and extruded samples were examined by Image Analyzer. Experimental observation revealed that with increase in volume percent of SiC particles, the grain size and silicon phase of the $Al-Si/SiC_p$ composites become finer, the shape of Si phase is changed from blocky to granular type, and aspect ratio of Si phase tend to become unity. Wear-tests with various sliding velocities, show that the wear resistance of spray cast specimen is increased remarkably compare to the permanent mold cast specimen at the sliding velocity range of $1.98{\sim}2.38m/sec$.. Microstructural observations for the worn surfaces of specimens revealed that wear resistance of Al-Si alloys at certain sliding velocities could be improved not only by the fine grain size of aluminum matrix but also the fine size and granular shape of silicon phases. The wear resistance of $SiC_p$ reinforced aluminum composites was found to be sensitive to the volume percentage of the reinforcing particles. The worn surfaces with various sliding velocities, show that change in wear mechanism seems to occur at the sliding velocity of near 2m/sec for all samples, and such a change in mechanism is delayed with increase in $SiC_p$ volume fraction.