• Journal of Powder Materials
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• v.7 no.1
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• pp.50-54
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• 2000

In order to reduce the sintering temperature of iron based sintered parts, sinteing properties of iron-copper prealloyed powder were investigated at various temperatures in the range of 700∼890$^{\circ}C$, and than the rusults were compared with those of the conventional iron-copper-tin compact using elemental powders, The using of prealloyed as a new process improved its sintering performance at lower temperature than elemental powder as the conventional process. The relative sintered density and radial crushing stength of the compact using prealloyed were higher than those of using elemental powder at all sintering temperature. For example, the radial curength of the compact using powder was about 50kg/mm2 at 700$^{\circ}C$, while that of the compact using elemental powder sintered at 890$^{\circ}C$ was 43kg/mm2.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.160-161
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• 2006

Seasonal changes have been recognized in particle characteristics and forming characteristics of iron powder with insulated coating for a compacted magnetic core because of its high hygroscopicity, due to its phosphate coating and resin binder additives. For this reason, particle characteristics and molding characteristics of the powder with diverse water absorbtivity have been studied. The result shows that the higher the volume of absorbed water, the worse the fluidity becomes, resulting in the reduction in both springback during the molding process and expansion reduction after the heat treatment. The requirement on dimension accuracy for the finished product can be satisfied with an additional drying process on the material powder, which contributes to maintain its water volume constant.

• Journal of Welding and Joining
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• v.15 no.4
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• pp.154-165
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• 1997

Abrasive wear characteristics of high Cr white cast iron-based hardfacing were investigated using the rubber wheel abrasion wear test method according with the ASTM G65-85. Mild steel was also tested for comparison with high Cr cast iron hardfacing. Wear experiments, where the applied force, wheel revolution rate and abrasive powder feed rate were selected as test valuables, were planned and analyzed by response surface method to evaluate wear statistically and quantitatively. Weight loss of high Cr cast iron hardfacing was mostly affected by the applied force and wheel revolution rate, and little by the powder feed rate. Weight loss of mild steel was greatly affected by the wheel revolution rate and powder feed rate, and slowly and steadily increased with the applied force. Abrasive wear mechanism of high Cr cast iron and mild steel was discussed in the light of the wear test results.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.446-447
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• 2006

Magnetic oxide-coated iron nanoparticles with the mean size ranging from 6 to 75 nm were synthesized by aerosol method using iron carbonyl as a precursor under the flowing inert gas atmosphere. Oxide shells were formed by passivation of asprepared iron particles. The influence of experimental parameters on the nanoparticles' microstructure, phase composition and growth behavior as well as magnetic properties were investigated and discussed in this study.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.77-78
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• 2006

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1187-1188
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• 2006

This paper compares the effect of using different types of iron powders for the preparation of $Sm_2Fe_{17}$ by calciothermic reduction-diffusion (CRD). Three types of iron powder were used: carbonyl, sponge and water atomized. The results show that, when immediately nitrogenated after the CRD process, $Sm_2Fe_{17}$ prepared from sponge and water atomized iron powders yield $Sm_2Fe_{17}N_3$-magnets with a high degree of texture. However, after a suitable treatment with hydrogen followed by nitrogenation, $Sm_2Fe_{17}$-powders made from Carbonyl iron produce magnets with the best quality regarding coercivity, remanence and degree of texture.

• Journal of Powder Materials
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• v.20 no.1
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• pp.1-6
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• 2013

The key concept of nanopowder agglomerate sintering (NAS) is to enhance material transport by controlling the powder interface volume of nanopowder agglomerates. Using this concept, we developed a new approach to full density processing for the fabrication of pure iron nanomaterial using Fe nanopowder agglomerates from oxide powders. Full density processing of pure iron nanopowders was introduced in which the powder interface volume is manipulated in order to control the densification process and its corresponding microstructures. The full density sintering behavior of Fe nanopowders optimally size-controlled by wet-milling treatment was discussed in terms of densification process and microstructures.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.740-741
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• 2006

The achievement of high density at reasonable cost is one of the major challenges of the P/M industry. One of the key factors contributing to the compressibility of a mix is the lubricant. New experimental lubricants enabling higher green density by conventional compaction or temperature-controlled die compaction were identified. The compaction and ejection characteristics of these new lubricants as measured with a fully instrumented lab press are presented and compared to that of conventional lubricants.

• Resources Recycling
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• v.28 no.5
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• pp.74-79
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• 2019

The effects of equivalent of iron powder, particle size, agitation speed on the removal efficiency of copper ion were investigated by adding iron powder as cementation agents to simulated mine drainage solution with 117.15 mg/L Cu ion. The 50 % of Cu was removed at 90 min with 2 equivalent of iron powder while more than 99 % of Cu was removed at 60 min with 16 equivalent at 200 rpm and $20^{\circ}C$. The removal efficiencies of Cu ion were not different using 2 equivalent of $48{\mu}m$ and $150{\mu}m$ iron powder, and the removal efficiency increased rapidly with increasing the agitation speed to more than 400 rpm. This lower removal efficiency resulted from agglomeration of iron powder observed by SEM, which could reduce the effective specific surface area. More than 99 % of copper ion was removed using 2 equivalent of $48{\mu}m$ iron powder at 60 min, 600 rpm and $20^{\circ}C$.

• Journal of Powder Materials
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• v.5 no.4
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• pp.299-302
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• 1998

Dimensional accuracy is one of the most important issues in the production of sintered parts. The iron-copper-carbon system is commonly used alloys in sintered structural parts production. The dimensional control of these alloys, however, is not easy because of their complex sintering behavior. This study is an effort to clarify the influence of common factors on dimensional change of Fe-Cu-C sintered structural parts. We determined the effect of such various parameters as chemical composition, particle diameter, compact density, sintering temperature and sintering time on dimensional changes. Consequently, we obtained a useful formula to predict the final dimension in function of these parameters. The effect of typical impurities in copper powder on the dimensional change of sintered parts has also been described.