• Journal of the Korean Society for Precision Engineering
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• v.14 no.9
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• pp.146-154
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• 1997

Ion implantation has been used successfully as a surface treatment technology to improve the wear. fatigue and corrosion resistances of materials. A modified surface layer by ion implantation is very thin(under 1 m), but it has different mechanical properties from the substrate. It has also different wear characteristics. Since wear is a dynamic phenomenon on interacting surfaces with relative motion, an effective method for investigtating the wear of a thin layer is the observation of wear process in microscopic detail using in-situ system. The change of wear properties produces the transition of wear mode. To know the microscopic wear mechanism of this thin layer, it is very important to clarify its microscopic wear mode. In this paper, using the SEM and AFM Rribosystems as in-situ system, the microscopic wear of Ti ion-implanted 1C-3Cr steel, a material for roller in the cold working process, was investigated in repeated sliding. The depth of wear groove and the speciffc wear amount were changed with transition of microscopic wear mode. The depth of wear groove with friction cycles in AFM tribosystem and specific wear amount of Ti ion-implanted 1C-3Cr steel were less about 2-3 times than those of non-implanted 1C-3Cr steel. The microscopic wear mechansim of Ti ion-implanted 1C-3Cr steel was also clarified. The microscopic wear property was quantitatively evaluated in terms of microscopic wear mode and specific wear amount.

• Journal of Korea Foundry Society
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• v.11 no.6
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• pp.475-481
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• 1991

In this study the fabrication technology and mechanical properties of AC8A/$Al_2O_3$ Composites by squeeze casting process were investigated to develope for application as the piston materials that require good friction, wear resistance, and thermal stability. AC8A/$Al_2O_3$ composistes without a porosity and the break of preform were fabricated at the melt temperature of $740^{\circ}C$, the preform temperature of $500^{\circ}C$, and mold temperature of $400^{\circ}C$ under the applied pressure of $1200kg/cm^2$ as the results of the observation of microstructures. As the results of this study, the tensile strength of AC8A/$Al_2O_3$ composites was not increased linearly with $Al_2O_3$ volume fraction and so it seemed not to agree with the rule of mixture, which had been used often in metal matrix composite. Also the tensile strength after thermal fatigue test was little different from that before the test. Consequently it was thought that AC8A/$Al_2O_3$ composites fabricated under our experimental conditions had a good thermal stability and subsequently a good interface bonding. Wear rate(i.e., volume loss per unit sliding distance) of AC8A/$Al_2O_3$ composites was decreased with $Al_2O_3$ volume fraction and the sliding speed at both room temperature and $250^{\circ}C$ and so there was a good correlation between wear rate and hardness. Also the wear rate of AC/8A20% $Al_2O_3$ composities was obtained the value of $1.65cm^3/cm$ at sliding speed of 1.14m/sec as compared with about $3.0\;{\times}10^{-8}cm^3/cm$ hyereutectie Al-Si alloy(Al-16%Si-2%Cu-1%Fe-1%Ni), which applied presently for piston materials. The wear behavior of $Al_2O_3$ composites was observed to a type of abrasive wear by the SEM view of wear surface.

• Journal of Korea Foundry Society
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• v.19 no.1
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• pp.24-32
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• 1999

A series of investigations for Austempered Ductile Iron (ADI) castings were carried out by using the specimens with various chemical compositions and heat treatment conditions. The rolling wear characteristics of alloyed austempered ductile irons under an unlubricated dry rolling condition was evaluated by the Amsler type test with 9.09% sliding ratio. Generally, the wear amount was increased with the austempering temperature and decreased when the hardness of the matrix was higher. The alloying elements also influenced the austempering reaction, the microstructure and the mechanical properties. In this study, the mechanical properties (i.e.) ultimate tensile strength (UTS), hardness, elongation) and the wear resistance are analysed to show the relationship between the alloying elements and the austempering temperatures. Mo, Cu and Ni are alloyed individually or in combination. It has been found that when Cu and Ni alloyed individually to a casting, the wear amount is increased than others with elements alloyed in combination. The amount of rolling wear loss was decreased when Mo was alloyed in cast iron, individually or in combination.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.06a
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• pp.47-52
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• 1999

In recent years, the micro-tribological behavior of silicon has been the topic of much interest. peformance of thin film under light load is important for potential applications in MEMS. In this work under light load and various humidity, the tribological behavior of undulated surface with various width and shape was Investigated. The results show that undulated surface of linear type had good tribological properties abrasive wear occur depending on the sliding condition. Also the effect of humidity on friction and wear was not important if exist undulation. Finally, undulations on HDD were found to be effective in trapping wear particles.

• Tribology and Lubricants
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• v.9 no.2
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• pp.56-62
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• 1993

Al-Pb-Cu and Al-Si-Pb-Cu bearing alloys were produced by forced-stirring method and water-cooled copper mold casting to investigate the effect of the precipitation hardening on the wear properties. Sliding of produced alloy pin against a steel disc were performed under various applied loads. Lowering the wear rate and material transfer phenomena were explained by the strengthening of $\theta'$ precipitates on AI matrix. The transmission electron microscope observation reveals the role of the precipitates in the alloys with Cu. The movement of dislocations was hindered by precipitates which resulted in the reduction of plastic deformation at the worn surfaces.

• 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.

• Tribology and Lubricants
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• v.15 no.1
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• pp.29-38
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• 1999

In recent years, the tribological behavior of coated ceramic material has been the issue of much interest. Particularly, the understanding of the tribological performance of thin film under light load is important for its potential in applications of MEMS. The friction and wear behavior of ceramic material that occur at light load depends on several factors such as surface roughness, contact area and material properties. In this work, the tribological behavior of coated silicon under light load and low speed was investigated. Particularly, the effects of coated materials, humidity and undulated surface were also studied. The results show that the effect of humidity on fiction was influenced by the apparent area of contact between the two surfaces. Also both adhesive and abrasive wear occurred depending on the sliding condition. Finally, undulations on the silicon wafer were found to be effective in trapping wear particles and resulted in the reduction of friction.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.04a
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• pp.108-114
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• 1998

The mechanical characteristics of the high speed steel by powder metallurgy process(PM-HSS) has been reported to improve with several alloying constituents, such as high carbon, vanadium and cobalt. In this paper, sliding wear test has been conducted using a pin-on-disc machine for three PM-HSS which contains 0%, 5% and 12% cobalt respectively, in order to evaluate the effect of cobalt on wear properties of PM-HSS. The results of this study showed that the wear resistance of PM-HSS has been increased by the addition of cobalt on the range of experimental friction velocities. When compared with the effect of addition of cobalt, the wear resistance of PM-HSS with 5% cobalt has been found to be superior to that of PM-HSS with 12% cobalt.

• Transactions of the Korean Society of Mechanical Engineers
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• v.8 no.3
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• pp.217-223
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• 1984

An attempt is made to predict the wear behavior of ion-nitrided metal, when wear arises from asperity interactions. The analysis demonstrates that wear mechanisms are not inconsistent with observed behavior, indicates and approaches to a better appreciation of the effects of such factors as nitrided layer formation and surface topographical features. It was found on ion-nitriding that penetration rate and case development are faster and wear properties of the final product are more improved than conventional gas and salt-bath methods of nitriding.

• Proceedings of the Materials Research Society of Korea Conference
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• 2005.05a
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• pp.267-267
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• 2005