• Proceedings of the KSME Conference
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• 2000.04a
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• pp.772-779
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• 2000

The friction and wear behavior of short carbon fiber reinforced polyetheretherketone was studied experimentally under dry sliding conditions against SCM440(AISI 4140) disks with a different surface roughness and hardness at the low sliding speeds and the high pressures on a pin-on-disk apparatus. Under the low disk surface roughness value the earsplitting noise and stick-slip were occurred. The increased adhesion friction and wear factor with stick-slip made the friction and wear behavior worse. Under the high disk surface hardness the break and falling-off of carbon fibers were accelerated. The carbon fibers fallen off from the matrix were ground into powder between two wear surfaces and this phenomenon caused a abrasive friction and wear factor to increase. So the friction and wear behavior became worse. With the transfer film made of wear particles formed on a disk, the carbon powder film formed on a pin lowered a friction coefficient.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.631-632
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• 2006

Cr-C-Ni composites were synthesized in situ from elemental powders of Cr, Ni and C by high energy milling followed by reactive sintering. The milled powders with the grain size in nano-scale were pressed to compacts and sintered. During the following thermal treatment at first the chromium carbide was formed and then the $Cr_3C_2-Ni$ cermets were sintered in one cycle. The interface between the binder phase and the carbide grains of the in situ composite has a good bonding strength as it is not contaminated with oxidation films or other detrimental surface reactions.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.9
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• pp.1013-1018
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• 2014

Magnetic Abrasive Polishing (MAP) process is a nontraditional method for polishing the surface of workpiece by using the flexibility of tool. At present, a mixture of polishing abrasives and ferrous particles is used as the tool in the MAP process. Previously, an experiment was conducted with different sizes of polishing abrasives with an aim to improve the polishing accuracy. However, the sizes of ferrous particles are also expected to have a dominant effect on the process, warranting a study on the effect of the size of ferrous iron particles. In this study, an experiment was conducted using three different sizes of ferrous particles. Iron powder of average diameters 8, 78 and $250{\mu}m$ was used as ferrous particles. The effect of each ferrous particle size was evaluated by comparing the improvements in surface roughness. The particle size of a ferrous iron was found to play a significant role in MAP and particles of $78{\mu}m$ facilitated the best improvement in surface roughness.

• Polymer(Korea)
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• v.26 no.6
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• pp.803-811
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• 2002

In this study the wear behavior of ultra high molecular polyethylene (UHMWPE) filled with kaolin particles by different methods was investigated. UHMWPE/kaolin composites were prepared by two different methods: polymerization-filling and powder mixing. Particularly in a powder mixing method. Particle dispersion and wear property according to powder mining method were examined. It was found from wear test that filling of inorganic filler into UHMWPE by polymerization filling was more effective way than by powder mixing method in improving Wear resistance of UHMWPE. It was also confirmed that abrasive wear was dominant wear mechanism and particle dispersion in the composite as well as interface property was an important factor in controlling the wear behavior of the resulting composites.

• Journal of Powder Materials
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• v.18 no.3
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• pp.290-296
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• 2011

Titanium carbonitride is more perspective materials compared to titanium carbide. It can be used in tool industry and special products because of its higher strength, abrasive wear-resistance and especially its strong chemical stability at high temperatures. We produced STS+TiCxNy composite by the spark plasma sintering for higher strength and studied the characteristics. The planar and cross-sectional microstructures of the specimens were observed by scanning electron microscopy. Characterizations of the carbon and nitride phases on the surface of composite were carried out using an X-ray diffractometer. During annealing TiCxNy particles diffusion into STS 430 was observed. After annealing, sintering isolations between particles were formed. It causes decreasing of mechanical strength. In addition when annealing temperature was increased hardness increased. Heterogeneous distribution of alloying elements particles was observed. After annealing composites, highest value of hardness was 738.1 MHV.

• Journal of Powder Materials
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• v.16 no.6
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• pp.416-423
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• 2009

Diamond/SiC composites are appropriate candidate materials for heat conduction as well as high temperature abrasive materials because they do not form liquid phase at high temperature. Diamond/SiC composite consists of diamond particles embedded in a SiC binding matrix. SiC is a hard material with strong covalent bonds having similar structure and thermal expansion with diamond. Interfacial reaction plays an important role in diamond/SiC composites. Diamond/SiC composites were fabricated by high temperature and high pressure (HPHT) sintering with different diamond content, single diamond particle size and bi-modal diamond particle size, and also the effects of composition of diamond and silicon on microstructure, mechanical properties and thermal properties of diamond/SiC composite were investigated. The critical factors influencing the dynamics of reaction between diamond and silicon, such as graphitization process and phase composition, were characterized. Key factor to enhance mechanical and thermal properties of diamond/SiC composites is to keep strong interfacial bonding at diamond/SiC composites and homogeneous dispersion of diamond particles in SiC matrix.

• Journal of Powder Materials
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• v.25 no.5
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• pp.395-401
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• 2018

The improvement of dispersion stability for the primary polishing slurry in a CMP process is achieved to prevent defects produced by agglomeration of the slurry. The dispersion properties are analyzed according to the physical characteristics of each silica sol sample. Further, the difference in the dispersion stability is confirmed as the surfactant content. The dispersibility results measured by Zeta potential suggest that the dispersion properties depend on the content and size of the abrasive in the primary polishing slurry. Moreover, the optimum ratio for high dispersion stability is confirmed as the addition content of the surfactant. Based on the aforementioned results, the long-term stability of each slurry is analyzed. Turbiscan analysis demonstrates that the agglomeration occurs depending on the increasing amount of surfactant. As a result, we demonstrate that the increased particle size and the decreased content of silica improve the dispersion stability and long-term stability.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.6
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• pp.930-937
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• 2001

The friction and wear behavior of short carbon fiber reinforced polyetheretherketone was studied experimentally under dry sliding conditions against SCM440(AISI 4140) disks with different surface roughness and hardness at the low sliding speeds and the high pressures on a pin-on-disk apparatus. Under the low disk surface roughness value the earsplitting noise and stick-slip were occurred. The increased adhesion friction and wear factor with stick-slip made the friction and wear behavior worse. Under the high disk surface hardness the break and falling-off of carbon fibers were accelerated. The carbon fibers fallen off from the matrix were ground into powder between two wear surfaces and this phenomenon caused abrasive friction and wear factor to increase. So the friction and wear behavior became worse. With the transfer film made of wear particles formed on a disk, the carbon powder film formed on a pin lowered a friction coefficient.

• Korean Journal of Metals and Materials
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• v.48 no.11
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• pp.1003-1008
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• 2010

In this study, the effect of the reinforcement on the wear behaviour and mechanical properties of hypereutectic Al-Si alloys was investigated. The Gas atomized hypereutectic Al-20Si alloy powders were mixed with 1, 3, and 5 wt.% AlN and TiC ceramic particles and consolidated by hotpress. The Al-20Si powder has both finely dispersed primary Si phases and eutectic structures. The Al-20Si-AlN, TiC composites showed that the reinforcements were distributed along the boundary of the Al-20Si alloy. The UTS increased with increasing the AlN, TiC contents. At a lower load, with an increasing weight fraction of reinforcements, the wear rate decreased in both composites and the wear mechanism was adhesive wear. At a higher load, the shape of the debris changes the mechanism of the AlN composites to abrasive-adhesion wear and this resulted in an increase of the wear rate.

• Journal of the Korean Ceramic Society
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• v.31 no.10
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• pp.1169-1175
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• 1994

Five Al2O3/SiC/metal composites with four different particle sizes of green SiC abrasive grains are grown by the directed oxidation of an commercially available Al-alloy. Oxidation was conducted in air at 100$0^{\circ}C$, 96 hours long. Slip casted SiC-fillers were placed on the alloy or SiC powder deposited up to the required layer thickness. Their microstructures are described and measurements of density, elastic constants, frexural strength, fracture toughness and work of fracture are reported. The results are compared with those of commercial dense sintered Al2O3. The properties of produced materials have a strong relationship to not only the properties of Al2O3, SiC, Al and Si but also to the phase share and phase distribution. The composite materials are dense (0.5% porosity), tough (KIC = 3.4~6.4 MPa{{{{ SQRT { m} }}), strong ({{{{ sigma }}B = 170~345 MPa) and reasonably shrinkage free producible. The reinforcements is attained mainly through the plastic deformation of ductile metal phase.