• Journal of the Korean Society for Precision Engineering
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• v.10 no.3
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• pp.31-40
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• 1993

The vibration-proof material normally used in structural components of precision machinery or measuring instruments requires higher damping in vibration and better characteristics in dimensional stability and rigidity to accomplish the quality assurance of the products. In this study the ferrite-resin material, which is the mixture of epoxy resin and the oxidized steel (Fe$_{3}$O$_{4}$: ferrite) in consideration of characteristics of aggregator and binder, is developed and investigated as one of vibration-proof materials. Four kinds of composite plates for experiments are made by adding another filler materials such as steel powder, granite powder and carbon-fiber sheet to the basic ferrite-resin matrix. Their characteristics are compared with a cast iron specimen which has the same bending rigidity as other specimens. The ferrite-resin material gives the best damping effect in the motor-induced vibration test. Therefore, the material can be applied to the manufacturing industry for vibration damping of machine elements.

• Journal of the Korea Safety Management & Science
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• v.2 no.4
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• pp.197-208
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• 2000

ABS sensor ring has been manufactured by powder metallurgy (P/M) method using 400 series ferrite stainless steel. The results are following. It is supposedly sufficient to use for control computer due to good experimental results of magnetic characteristics. Compared with sensor ring made by iron, 400 series ferrite stainless steel has shown a good corrosion resistance without an addition surface treatment. Thus the decreasing production process has been obtained. As a result mechanical characteristics of hardness and tensile test, 400 series ferrite stainless steel shown a good endurance when it is combined to constant velocity joint(C/V), and has a good hardness properties endurable to sand and pebble impact. The products before sintering are much more corrodible in the condition of spray test of salt water and ammonia than humidity and nitrogen condition.

• Journal of Powder Materials
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• v.11 no.6 s.47
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• pp.510-514
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• 2004

Iron-carbon nanocapsules were synthesized by plasma arc discharge (PAD) process under various atmosphere of methane, argon and hydrogen gas. Characterization and surface properties were investigated by means of HRTEM, XRD, XPS and Mossbauer spectroscopy. Fe nanocapsules synthesized were composed of three phases $({\alpha}-Fe,\;Y-Fe\;and\;Fe_{3}C)$ with core/shell structures. The surface of nanocapsules was covered by the shell of graphite phase in the thickness of $4{\~}5$nm.

• Journal of Yeungnam Medical Science
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• v.28 no.2
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• pp.145-152
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• 2011

Background: To evaluate the changes in the radiation dose and temperature distribution on irradiated egg albumin and nanoparticle ($Fe_3O_4$) powder mixed egg albumin. Methods: A new type of phantom was designed by fabricating a $30{\times}30{\times}30cm$ acryl square inside a $3{\times}3{\times}3cm$ small square and dividing it into two parts. In the control group, only egg albumin was irradiated, and in the test group, 25 nm 20 mg/cc, 25 nm 40 mg/cc, and 1 um 40mg/cc nanoparticles with egg albumin were irradiated. The radiation isodose distributions and temperature changes were then observed. Results: No significant changes were observed in the radiation dose and temperature distribution. Conclusion: The nanoparticles were considered not to have had any effect on the radiation dose and temperature distribution under the experimental conditions. Further studies can be conducted based on the changes in the mixture material.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.927-929
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• 2014

MRE(Magneto-rheological Elastomer) is a material which shows reversible and various modulus in magnetic field. Comparing to conventional rubber vibration isolator, MREs are able to absorb broader frequency range of vibration. These characteristic phenomena result from the orientation of magnetic particle (i.e., chain-like formation). Magnetic reactive powder(MRP), having rapid magnetic reaction, was selected as a magnetic particle to give magnetic field reactive modulus. The mechanical properties of manufactured MREs were measured with the application of magnetic field. The analysis of MR effect was carried out by FFT analyzer with various induced current. As induced magnetic field intensity increased and coated with MRP, increment of MR effect was observed.

• Journal of Welding and Joining
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• v.20 no.3
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• pp.54-59
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• 2002

Overlays is a treatment of the surface and near-surface regions of a material to allow the surface to perform functions that are distinct from those frictions demanded far the bulk of the material. Welding, thermal spray, quenching, carburizing and nitration have been used as the surface treatment. Especially, weld overlay is a relatively thick layer of filler metal applied to a carbon or low-alloy steel base metal for the purpose of providing a wear resistant surface. In this study, weld overlay was performed by MAG welding on the base metal(SS400) with filler metal which contain composite powders($Cr_3C_2+Mn+Mo+NbC$) and solid wire(JIS-YGW11). Characteristics of hardness and wear resistance on overlays were analyzed by EDS, EPMA, XRD and microstructures. Carbide formations were $M(Cr, Fe)_7C_3$ and NbC phases. And carbide volume fraction, hardness and specific wear resistance of overlays were increased with increasing powder feed rate and decreasing wire fred rate. Hardness and wear resistance were almost proportioned to carbide volume fraction of overlay.

• Journal of Powder Materials
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• v.18 no.5
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• pp.417-422
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• 2011

Hydrophobic nanodiamond (ND) were dispersed in engine oil (Helix Oil, Shell co.) as an additives to improve tribology properties. In this study, nanodiamond prepared by an explosive method was used. Tribology properties of both pure Helix oil and engine oil containing ND additive were evaluated. The rotating disks were made of Gray Cast Iron (240 Hv) and SKD11 (710 Hv). Surface topographies of the disks' wear tracks and friction coefficient were compared. The results show that nanodiamond-dispersed lubricants are capable of reducing these metals' wear loss. The friction coefficient is strongly affected to the hardness of wear track.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.3
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• pp.274-279
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• 2011

In this study, new abrasives that were composed of iron powder and carbon nanotube (CNT) particle were attempted to be abrasives for magnetic abrasive polishing. Because the CNT particles itself are very small ones with high hardness and magnetic strength, these properties are effective for magnetic abrasive polishing of nonmagnetic materials. As an experimental result for evaluating the machining characteristics in magnetic abrasive polishing, the CNT particles showed better performance than the conventional abrasives such as Fe and CBN powder.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.570-571
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• 2006

The mixed atomized iron powders with 0.3% graphite and 1% Ni powders were cold pressed and sintered at $1200^{\circ}C$ for 30 min under pure Ar gas atmosphere. Some of the sintered specimens were intercritically annealed at $760^{\circ}C$ and quenched in water (single quenching). The other sintered specimens were first fully austenized at $890^{\circ}C$ and water quenched. These specimens were then intercritically annealed at $760^{\circ}C$ and re-quenched in water. The experimental results showed that the wear coefficient effectively decreased in the double quenched specimen.

• Journal of Powder Materials
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• v.8 no.4
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• pp.258-267
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• 2001

In this work, the conventional transient liquid phase(TLP) bonding was modified. An attempt was made of using a liquid phase sintered alloy, which will be a liquid phase coexisting with a solid phase at the bonding temperature, as an interlayer for bonding metals. With an aim of revealing the fundamental features of this modified TLP bonding, the kinetics concerned with the growth of solid particles and the isothermal solidification process in Fe-1.16wt%B and Fe-4.5wt%P interlayers for the bonding pure iron, as well as the morphological change of the solid particle, were investigated.