• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.233-234
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• 2002

Diamond composites hold promise as a tribological material because of low friction and high wear resistance. We studied friction and wear of polyimide-20vol% PTFE-diamond composites in open air at room temperature, focusing on the effects of diamond size, and diamond content, sliding conditions, and mating material. Friction coefficient and wear tend to Increase with increasing diamond size and content. Composites of appropriate diamond size and content showed a friction coefficient below 0.1 and specific wear of $10^{-7}\;mm^3/Nm$. Friction and wear of composites sliding against stainless steel were higher than those of Al_2O_3$ an increase that became increasingly not able with increasing diamond size.

• Journal of Powder Materials
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• v.7 no.1
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• pp.12-18
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• 2000

Effects of the microstrucrure of rapidy solidified Al-Pb-Cu-Mg alloys on the wear investigated. In order to overcome the miscility gap between Al and pb under equilibrium conditions, both in the solid and the liquid states, the alloy were rapidy solidifies to produce them in a segregation-free condition. Although the Pb particles showed relatively fine dispersion in the Al matrix in all the alloys by this process. the Al-16Pb alloy was found to have the most favorable microstructure with discretre with discrete Pb particles of abount 0.5 ${\mu}$m in size. With the addition of Cu and Cu-Mg to Al-16Pb, cellular structures were newly formed; not seen in the binary Al-Pb alloy. Wear properties of the Al-Pb binary alloys measured as a function of the sliding speen, sliding distance, and applied load showed that the Al-16Pb alloy has the best wear resistance, as expected from the fine microstructural features in this alloy. The were resistance of the alloy containing Cu-and Cu-Mg was higher than that of the Al-16Pvb alloy, due to matrix strengthening by precipitation hardeing. The wear mechanism was identified by examining the traces and wear debris.

• 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.

• KSTLE International Journal
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• v.2 no.1
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• pp.17-21
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• 2001

Surface treatment technologies are frequently used to improve mechanical properties of surface layers of machinery components in many practical situations. Surface hardness of piston in the oil hydraulic piston pumps is very important about wear resistance. To improve hardness, wear resistance of the oil hydraulic axial piston pump, it is needed to know the surface layer characteristics in the sliding contact parts. This paper reports an experimental study on surface treatment characteristics in the piston of the oil hydraulic axial piston pump. We investigated the surface wear of a piston between untreated and nitriding-treated surfaces. We obviously observed that the surface hardness of piston in the oil hydraulic axial piston pump plays an important role to have wear resistance and remain a longer life.

• 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.

• Korean Journal of Materials Research
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• v.8 no.12
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• pp.1138-1145
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• 1998

The sliding wear behavior of Ni-base hardfacing alloy, Deloro 50, was investigated at the contact stresses of 15ksi and 30ksi under the various wear environments. In air at room temperature, Deloro 50 showed lower wear resistance than Stellite 6 even at 15ksi due to the occurrence of severe adhesive wear. This seems to be caused by the lower hardness and work- hardening rate of Deloro 50 than those of Stellite 6. In water at room temperature, Deloro 50 showed as good wear resistance as Stellite 6 at 15ksi. It was considered to be due to that water could effectively prevent metal to metal contact through contacting asperities. However, Deloro 50 showed severe adhesive wear at 30ksi in water at room temperature. It seems to be that the water could not suppress adhesion wear at 30ksi. At $300^{\circ}C$ in air, Deloro 50 exhibited higher wear resistance than Stellite 6 even at 30ksi. It was considered that the oxide glaze layers formed on wear surface during sliding, effectively prevented direct metal-to-metal contacts.

• Journal of the Korean Society for Heat Treatment
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• v.13 no.2
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• pp.71-84
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• 2000

A study on adhesion and wear resistance of VC(vanadium carbide) coating on die steels, STD11 and STD61, has been carried out. The VC coating on the die steels was made by immersing them in molten borax bath, a kind of TRD(thermo-reactive deposition and diffusion). Adhesion strength and wear resistance were investigated using scratch test, indentation test and plate-disc test(Ogoshi type) respectively. The influence of sliding distance on the amount of wear has been determined and dominant wear mechanisms has been characterized using optical microscopy, scanning electron microscopy and EDS spectroscopy. The critical adhesion strength($L_c$) between VC coating layer and substrate(STD11) was increased to 60N($L_c$) in the scratch test. In the case of STD61, the strength increased to 24N. The wear resistance of VC coated die steels was excellent because the diffusion layer formed just below the coating layer. The dominant wear mechanism was identified as adhesive wear for VC coating die steels which were worn by combination of cracking and plucking of VC fragments and disc.

• Journal of the Korea Institute of Building Construction
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• v.5 no.1 s.15
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• pp.53-61
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• 2005

The purpose of this study presents useful data on the choice or development of floor covering from slip viewpoint by examining closely the impact of the changes in sliding experiments due to the wear of floor covering by walk. The result of wear practical test per ten thousand walks enforces some kind of popular floor covering and measure of coefficient of slip resistance as follows: (1) When surface of floor covering is in the state of wet, the degree of wear doesn't affect greatly in slip. (2) When surface of floor covering is in dry and clean state, most floor coverings have the tendency to lower the coefficient of slip resistance with the amount of walk on it. (3) Change in the tendency of slip resistance by wear appeared mainly due to the differences in the state of floor covering and organic floor covering appeared to have great reduction of coefficient of slip resistance than the inorganic ones. (4) According to the result of investigation on changes in tendency of coefficient of slip resistance due to the increase in the number of walk and if two hundred thousand walks were done, regardless of surface shape or kind of site, etc, the safety of floor covering, in slip viewpoint, greatly reduces.

• Journal of Welding and Joining
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• v.17 no.6
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• pp.62-69
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• 1999

The advantages of Thermal sprayed coatings as a replacement for cast iron liners are reduced weight, better heat transfer and reduced cost. One of the most important performance attributes of a cylinder bore coating is its wear resistance, since it must survive the abrasive sliding of both the piston rings and the piston skirt. In this study, composite powders were prepared by ball milling of Al-13Si-3Mg(wt%) alloy with SiC particles. The concentrations of SiC were 40 and 60wt%. The composite powders were sprayed using Metco-9MB plasma torch. Plasma sprayed coatings were heat-treated at 500℃ for 3 hours. The wear resistances of the plasma sprayed coatings were found to improve with heat treatment and superior to the commercially available G.C.I.(gray cast iron). AlSiMg-40SiC heat-treated coatings showed the best wear resistance in this study.

• The Korean Journal of Ceramics
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• v.1 no.4
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• pp.185-190
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• 1995

Tribological behavior of the diamond-like carbon (DLC) films sliding on floppy disk has been investigated. Hydrogenated DLC films have been prepared by plasma enhanced chemical vapor deposition (PECVD) using methane and hydrogen mixture in different volume ratios on ferrite substrates. DLC films show lower friction coefficients (0.2~0.4) than those of the uncoated ferrite(0.4~0.5). DLC films containing more hydrogen exhibit higher wear resistance. To investigate the roughness effect on wear, the substrates were polished with SiC papers prior to deposition. Too fine or too rough DLC surfaces result in poor wear resistance. Wear resistance of annealed DLC films at higher temperature slightly increases with respect to as-deposited film.