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Vol.48, No.7, 630 ~ 639, 2010
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| Title |
| Mixing Behavior and Microstructural Development During Fabrication of Fe Micro-nano-powder Feedstock for Micro-PIM |
| 이원식 Won Sik Lee , 이재성 Jai Sung Lee , 고세현 Se Hyun Ko , 유우경 Woo Kyung You |
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| Abstract |
| The present investigation has been performed on the mixing behavior and microstructural development during fabrication of Fe micro-nano powder feedstock for a micro-powder injection molding process. The mixing experiment using a screw type blender system was conducted to measure the variations of torque and temperature during mixing of Fe powder-binder feedstock with progressive powder loading for various nano-powder compositions up to 25%. It was found that the torque and the temperature required in the mixing of feedstock increased proportionally with increasing cumulative powder loading. Such an increment was larger in the feedstock containing higher content of nano-powder at the same powder loading condition. However, the maximum value was obtained at the nano-powder composition of not 25% but 10%. It was owing to the 'roller bearing effect' of agglomerate type nano-powder acting as lubricant during mixing, consequently leading to the rearrangement of micro-nano powder in the feedstock. It is concluded that the improvement of packing density by rearrangement of nano-powders into interstices of micro-powders is responsible for the maximum powder loading of about 71 vol.% in the nano-powder composition of 25%. |
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| Key Words |
| nanostructured materials, powder processing, microstructure, SEM, μ-PUM |
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