• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.596-596
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• 2006

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.173-174
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• 2006

X-ray analysis on iron ores and reduced iron powders revealed that the main acid-insoluble substances were hexagonal and tetragonal quartz, another substances were sillimanite, alumina-silicate, an unnamed zeolite, all contained Si and Al. Their particle size was in the range of $3{\sim}7\;{\mu}m$. Statistics analysis showed that the AIC for high-grade magnetite powder was $(0.130{\pm}0.010)%$) during the latest five months. The predicting value for reduced iron powder should be 0.179%. However, the testing value for reduced iron powder was $(0.192{\pm}0.014)%$. The limited difference of 0.013% might imply rare pollution coming from the reduction and milling processes. The most important step for control AIC should be the separation process of iron ore powders.

• 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.1014-1014
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• 2006

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.175-176
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• 2006

The filling property of the binder treated iron based powder made of atomized iron powder was compared with that of the one made of reduced iron powder. The latter one showed a better filling property than the former one, although the original reduced powder showed a worse flow rate. Changing the particle size distribution of the original atomized powder from wide to narrow like the original reduced iron powder, improved the filling property of the binder treated powder. As a result, the particle size distribution of the original iron powder was found to strongly affect the filling property of the binder treated powder.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.201-202
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• 2006

An apparatus measuring changes of various forces directly and continuously was developed by a way of direct touch between powders and transmitting force component, which can be used to study forces state of powders during warm compaction. Using the apparatus, warm compaction processes of iron-based powder materials containing different lubricants at different temperatures were studied. Results show that densification of the iron-based powder materials can be divided into four stages, in which powder movement changes from robustness to weakness, while its degree of plastic deformation changes from weakness to robustness.

• Journal of the Korean Society for Heat Treatment
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• v.9 no.1
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• pp.62-68
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• 1996

In order to establish making process of water atomized iron powder for powder metallurgy, effect of heat treatment condition on change of powder properties and impurities was investigated at each tempeature of $850{\sim}950^{\circ}C$. The results are as follows. Particle morphology of iron powder changed slightly from sphercial type to irregular type and the amount of fine particle decreased more and more with increasing of heat treatment time at each temperature. The flow rate and apparent desity of iron powder also decreased due to particle coalescence in order of $850^{\circ}C$, $950^{\circ}C$, $900^{\circ}C$. Those powder Properties became to decrease particularly at $900^{\circ}C$ in alpha iron region. On the other hand, residual carbon and oxygen contents in iron powder decreased extremely with increasing of heat treatment temperature and time.

• Journal of Powder Materials
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• v.20 no.3
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• pp.174-179
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• 2013

The study on the fabrication of iron powder from forging scales using hydrogen gas has been conducted on the effect of hydrogen partial pressure, temperature, and reactive time. The mechanism for the reduction of iron oxides was proposed with various steps, and it was found that reduction pattern might be different depending on temperature. The iron content in the scale and reduction ratio of oxygen were both increased with increasing reactive time at 0.1atm of hydrogen partial pressure. On the other hand, for over 30 minutes at 0.5 atm of hydrogen partial pressure, the values were found to be almost same. In the long run, iron metallic powder was obtained with over 90% of iron content and an average size of its powder was observed to be about $100{\mu}m$.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.482-483
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• 2006

Synthesis of iron nanopowder by room-temperature electrochemical reduction process of ${\alpha}-Fe_2O_3$ nanopowder was investigated in terms of phase evolution and microstructure. As process variables, reduction time and applied voltage were changed in the range of $1{\sim}20$ h and $30{\sim}40$ V, respectively. From XRD analyses, it was found that volume of Fe phase increased with increasing reduction time and applied voltage, respectively. The crystallite size of Fe phase in all powder samples was less than 30 nm, implying that particle growth was inhibited by the reaction at room temperature. Based on the distinct equilibrium shape of crystalline particle, phase composition of nanoparticles was identified by TEM observation.

• 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